Dissertations / Theses on the topic 'LASIK'
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Kamma, Christina-Stamatia. "Healing of LASIK flaps." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/54605/.
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The aim of this study was to obtain a better understanding in the healing of LASIK-like flaps using an in vitro organ culture method in bovine corneas. At early stages of the PhD, during protocol optimisation, a 5mm trephine was used to injure bovine corneas. At later stages a custom-made eye holder was used to induce LASIK-like incisions in corneas. Immunohistochemistry for a-smooth muscle actin (aSMA) and cytokeratin was used to monitor myofibroblast and epithelial cell expression, respectively, during the wound healing process. Additionally, the effect of certain cytokines (i.e. TNFa, Fas ligand, TGF-Pi and IL-la) was tested in terms of corneal transparency, myofibroblast expression and tissue mechanical strength during the healing process. The later series of experiments was an attempt to manipulate and improve wound healing after LASIK. Healing in this in vitro system closely followed the effects that are already known from the literature. In addition, preliminary evidence on the cytokine corneas proved that there is a correlation between cytokine type and concentration with the effect in tissue transparency, extend of wound healing response and tissue mechanical strength. X-ray diffraction also provided important information about collagen ultrastructural changes in the corneas during the healing process. Parameters such as fibrillar diameter, spacing, distribution and orientation were studied. Collagen fibrillar diameter and spacing remained constant for control corneas during the organ culture time-span, indicating that this in vitro system does not induce any swelling effects on the tissue. However, injured corneas became significantly swollen (p<0.05) during culture. Swelling effects were more severe in trephined corneas than in LASIK-like injured ones. However, collagen fibrillar diameter remained normal in the periphery of injured corneas, but it increased significantly in areas within and around the wound in trephined samples and in the flap incision site for LASIK-like ones. In both types of wounding, collagen orientation changes were observed and were associated with the process of creating the injury. However, in the case of trephine wounded corneas, tissue swelling and changes in collagen orientation reflected the processes of tissue repair. These differences will determine corneal stability and strength follow trauma and, possibly, refractive surgery. The transparency of the cornea depends on both the collagen and the interstitial proteoglycans. In order to obtain a better insight in ultrastructural changes during the wound healing process molecular modelling techniques were used in order to construct a theoretical model for the core protein of biglycan. This molecule is a dermatan sulphate proteoglycan and its numbers increase up to seven times during wound healing. It is considerably larger than the rest of proteoglycans and molecular modelling also revealed numerous potential collagen interaction sites.
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Yi, Fan, and n/a. "Optimal Algorithmic Techniques of LASIK Procedures." Griffith University. School of Engineering, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070216.152339.
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Clinical wavefront-guided corneal ablation has been now the most technologically advanced method to reduce the dependence of glasses and contact lenses. It has the potential not only to eliminate spherocylindrical errors but also to reduce higher-order aberrations (HOA). Recent statistics show that more than 96% of the patients who received laser in situ keratomileusis (LASIK) treatment reported their satisfaction about the improvement on vision, six months after the surgery. However, there are still patients complaining that their vision performance did not achieve the expectation or was even worse than before surgery. The reasons causing the unexpected post-surgical outcome include undercorrection, overcorrection, induced HOA, and other postoperative diseases, most of which are caused by inaccurate ablation besides other pathological factors. Therefore, to find out the method to optimize the LASIK procedures and provide a higher surgical precision has become increasingly important. A proper method to calculate ablation profile and an effective way to control the laser beam size and shape are key aspects in this research to resolve the problem. Here in this Master of Philosophy degree thesis, the author has performed a meticulous study on the existing methods of ablation profile calculation and investigated the efficiency of wavefront only ablation by a computer simulation applying real patient data. Finally, the concept of a refractive surgery system with dynamical beam shaping function is sketched, which can theoretically overcome the disadvantages of traditional procedures with a finite laser beam size.
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Yi, Fan. "Optimal Algorithmic Techniques of LASIK Procedures." Thesis, Griffith University, 2006. http://hdl.handle.net/10072/368097.
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Clinical wavefront-guided corneal ablation has been now the most technologically advanced method to reduce the dependence of glasses and contact lenses. It has the potential not only to eliminate spherocylindrical errors but also to reduce higher-order aberrations (HOA). Recent statistics show that more than 96% of the patients who received laser in situ keratomileusis (LASIK) treatment reported their satisfaction about the improvement on vision, six months after the surgery. However, there are still patients complaining that their vision performance did not achieve the expectation or was even worse than before surgery. The reasons causing the unexpected post-surgical outcome include undercorrection, overcorrection, induced HOA, and other postoperative diseases, most of which are caused by inaccurate ablation besides other pathological factors. Therefore, to find out the method to optimize the LASIK procedures and provide a higher surgical precision has become increasingly important. A proper method to calculate ablation profile and an effective way to control the laser beam size and shape are key aspects in this research to resolve the problem. Here in this Master of Philosophy degree thesis, the author has performed a meticulous study on the existing methods of ablation profile calculation and investigated the efficiency of wavefront only ablation by a computer simulation applying real patient data. Finally, the concept of a refractive surgery system with dynamical beam shaping function is sketched, which can theoretically overcome the disadvantages of traditional procedures with a finite laser beam size.Thesis (Masters)
Master of Philosophy (MPhil)
School of Engineering
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Ahmedova, Renin. "Förhållandena inom refraktiv kirurgi i Sverige, vilka metoder används och vilka komplikationer finns?" Thesis, Linnéuniversitetet, Institutionen för medicin och optometri (MEO), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-54189.
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Syfte: Studiens syfte var att undersöka hur refraktiv kirurgi ser ut i Sverige idag, vilka komplikationer som finns och vilka metoder som används genom att göra en kort redovisning av de vanligaste teknikerna FS-lasik, LASEK, TransPRK och RLE som finns inom refraktiv kirurgi och med hjälp av en enkät ta reda på de olika komplikationerna mellan olika åldersgrupper. Metod: En enkätstudie inom refraktiv kirurgi i Sverige genomfördes. Enkäten var webbaserad och skapad i Google Docs (http://docs.google.com). Enkäten innehöll totalt 11 frågor som handlade om patientens tidiga refraktion, operationsmetod och ögonhälsa efter operationen. Enkäten spreds via sociala medier som Facebook, Instagram, Twitter, olika forumsiter, samt mail. En del av enkäten var även fördelad på två olika ögonkliniker i Lund. Resultat: Resultaten av enkäten visar att det finns inte någon skillnad i komplikationsgraden mellan de olika åldersgrupperna och komplikationerna efter kirurgin beror på typen av metod och patientens synfel och brytningsfel. Slutsats: Vid de olika metoderna förekommer olika komplikationer och ju mer närsynt patienten är desto större är risken för komplikationer i samband med operationen.Refractive surgery is an effective method for correcting visual refractive errors. The method has evolved quickly over the past decade. The aim of this study was to examine what refractive surgery is in Sweden today. What complications exist and which methods are used, are described by making a presentation of the refractive surgery techniques FS-LASIK, LASEK, TransPRK and RLE. This was done by a survey to find out the various complications between different age groups. A web-based survey was disseminated trough social media like Facebook, different forum sites and e-mail. The survey was also submitted to various eye clinics. The respondents were asked questions about their age, gender, the surgical method used and the complications after surgery. The results of the survey showed that there is no difference in the complication rate between the different age groups. Complications only depend on the type of method used and the patient’s refractive errors.
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Wu, Yih-Tyng. "Change of line of sight after lasik /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488203857251318.
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Iribarne, Ferrer Yolanda. "Sensibilidad al contaste tras LASIK convencional y personalizado." Doctoral thesis, Universitat de Barcelona, 2006. http://hdl.handle.net/10803/1229.
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OBJETIVOS: Determinar la técnica de LASIK (convencional o personalizada) que consigue una mayor calidad visual en los pacientes intervenidos de cirugía refractiva (en términos de agudeza visual, sensibilidad al contraste y sensación subjetiva), así como comparar su efectividad, eficacia, predictibilidad, seguridad, estabilidad y su repercusión en las aberraciones corneales provocadas tras la cirugía.
MATERIAL Y METODOS:
En una muestra de 27 pacientes con las mismas características en los dos ojos se analiza la calidad visual del paciente, así como las aberraciones pre y postoperatorias tras la aplicación de cirugía refractiva corneal con láser Excímer, realizando un tratamiento convencional en un ojo del paciente y un tratamiento personalizado en el otro ojo. Se realizan controles postoperatorios al día siguiente de la cirugía, a la semana, al mes, a los tres, seis y doce meses.
La calidad visual del paciente se analiza en términos de agudeza visual, sensación subjetiva y sensibilidad al contraste con el test CSV-1000. Las aberraciones se han medido con un aberrómetro basado en el método de Hartmann-Shack. El láser se ha aplicado con el Technolas 217z, que posee la capacidad de realizar un tratamiento LASIK estándar o personalizado.
RESULTADOS:
El tratamiento personalizado consigue una calidad visual levemente superior a la técnica convencional en términos de agudeza visual (sobre todo en ganancia de líneas de visión) y sensibilidad al contraste, pero sin significación estadística a los 12 meses de la intervención.
La predictibilidad, eficacia, seguridad y estabilidad de ambos tipos de técnicas son similares. En cuanto a las aberraciones, el tratamiento personalizado ha conseguido reducir o inducir en menor grado aberraciones de tercer y cuarto orden, pero las de quinto orden han empeorado más en los ojos intervenidos con el tratamiento personalizado.
DISCUSIÓN:
Al comparar el tratamiento LASIK convencional de la miopía con el personalizado se puede llegar a afirmar que sólo se encuentran sutiles diferencias entre ellos (como la mayor ganancia de líneas de visión en el tratamiento personalizado) pero sin significación estadística. Esto podría ser debido a que las aberraciones de la población seleccionada no son muy elevadas. Por ello se puede considerar que la ablación personalizada puede lograr una mayor calidad visual tras cirugía refractiva si los pacientes tienen altos valores elevados de las aberraciones de alto orden.
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Mones, Chelsey. "The lasik experts| A small business plan proposal." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10076457.
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The LASIK market in Orange County, CA is extremely saturated, with the exception of the city of Laguna Niguel. This business plan proposes the creation of The LASIK Experts in Laguna Niguel to fulfill the need for such a LASIK center within the city. Based on the detailed financial projections prepared by the company’s management, it is estimated that a bank loan is necessary to begin the company’s operations successfully. The funds will be used to provide the initial working capital for the first three fiscal years.
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Tat, Lien Thieu. "LASIK: Clinical Results and Their Relationship to Patient Satisfaction." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1607.
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The aim of this study was to evaluate the safety and efficacy of LASIK as a refractive surgical procedure, using a repeated measures design to assess satisfaction of patients who had LASIK and to correlate clinical outcomes with detailed measures of patient satisfaction to document long-term viability, monitor changes over time and patients’ functional abilities post-operatively. Method In the study 216 post-LASIK subjects were randomly selected from among patients who underwent simultaneous bilateral LASIK using the Chiron Technolas 217C plano-scan excimer laser with the Chiron ACS (Automated Corneal Shaper) and the Hansatome microkeratome. The subjects were recruited from within one centre, and the procedures were performed by any one of three surgeons. The study also included 100 non-LASIK subjects as a control group, to compare and differentiate ocular symptoms and visual difficulties between LASIK and non-LASIK patients. Clinical data documented included visual acuity, subjective refraction, record of glasses and/or contact lenses prescription, corneal topography with EyeSys and Orbscan, slit lamp examination, surgical details, and any pre-existing eye disease/conditions and previous surgery or injury that might prevent the subjects from achieving their desired visual outcome post-operatively. Subjective patient satisfaction evaluation of the treatment group was assessed by subjects completing a survey questionnaire at 3 months, 6 months, 12 months and 24 months post-operatively. The control group subjects completed a comparable questionnaire and were assessed at baseline and 3 months later. Because the control group subjects did not have any surgical alterations, it was unnecessary for them to have more than one follow-up. Results LASIK achieved relatively high patient satisfaction, with only a small number of dissatisfied patients. It was effective in correcting myopia, hyperopia and astigmatism. However, there was some persistent under-correction in myopic spherical and minus cylindrical refractive errors. Hyperopic spherical correction was less effective, as there were more under- as well as over-correction, and the plus cylindrical correction tended to be under-corrected. The LASIK subjects’ post-operative distance uncorrected visual acuity was not as good as their pre-operative best corrected visual acuity, but it did not significantly correlate with patient satisfaction. The findings were consistent with other studies and confirmed the concept that patient satisfaction is not unidimensional and is not related to outcome solely in terms of visual acuity and residual refractive errors. Other contributing factors included problems with glare, rating of unaided distance and near vision, ability to drive at night, change in ability to perform social/recreational, home and work activities, change in overall quality of life, amount of information given prior to surgery, rating of surgery success, and surgery outcome relative to pre-operative expectations. These variables demonstrated distinctive differences between subjects who were satisfied and dissatisfied. Conclusions The findings of this study are consistent with those of earlier studies. However, the repeated measures design and the comparisons between LASIK subjects and the control group revealed some new insights that were previously undocumented. LASIK achieved high patient satisfaction, and factors associated with satisfaction were predictable, but sources of dissatisfaction were more idiosyncratic and contributing factors were identified.
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Tat, Lien Thieu. "LASIK clinical results and their relationship to patient satisfaction /." University of Sydney. Faculty of Health Sciences, 2006. http://hdl.handle.net/2123/1607.
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Doctor of Philosophy (PhD) OrthopticsThe aim of this study was to evaluate the safety and efficacy of LASIK as a refractive surgical procedure, using a repeated measures design to assess satisfaction of patients who had LASIK and to correlate clinical outcomes with detailed measures of patient satisfaction to document long-term viability, monitor changes over time and patients’ functional abilities post-operatively. Method In the study 216 post-LASIK subjects were randomly selected from among patients who underwent simultaneous bilateral LASIK using the Chiron Technolas 217C plano-scan excimer laser with the Chiron ACS (Automated Corneal Shaper) and the Hansatome microkeratome. The subjects were recruited from within one centre, and the procedures were performed by any one of three surgeons. The study also included 100 non-LASIK subjects as a control group, to compare and differentiate ocular symptoms and visual difficulties between LASIK and non-LASIK patients. Clinical data documented included visual acuity, subjective refraction, record of glasses and/or contact lenses prescription, corneal topography with EyeSys and Orbscan, slit lamp examination, surgical details, and any pre-existing eye disease/conditions and previous surgery or injury that might prevent the subjects from achieving their desired visual outcome post-operatively. Subjective patient satisfaction evaluation of the treatment group was assessed by subjects completing a survey questionnaire at 3 months, 6 months, 12 months and 24 months post-operatively. The control group subjects completed a comparable questionnaire and were assessed at baseline and 3 months later. Because the control group subjects did not have any surgical alterations, it was unnecessary for them to have more than one follow-up. Results LASIK achieved relatively high patient satisfaction, with only a small number of dissatisfied patients. It was effective in correcting myopia, hyperopia and astigmatism. However, there was some persistent under-correction in myopic spherical and minus cylindrical refractive errors. Hyperopic spherical correction was less effective, as there were more under- as well as over-correction, and the plus cylindrical correction tended to be under-corrected. The LASIK subjects’ post-operative distance uncorrected visual acuity was not as good as their pre-operative best corrected visual acuity, but it did not significantly correlate with patient satisfaction. The findings were consistent with other studies and confirmed the concept that patient satisfaction is not unidimensional and is not related to outcome solely in terms of visual acuity and residual refractive errors. Other contributing factors included problems with glare, rating of unaided distance and near vision, ability to drive at night, change in ability to perform social/recreational, home and work activities, change in overall quality of life, amount of information given prior to surgery, rating of surgery success, and surgery outcome relative to pre-operative expectations. These variables demonstrated distinctive differences between subjects who were satisfied and dissatisfied. Conclusions The findings of this study are consistent with those of earlier studies. However, the repeated measures design and the comparisons between LASIK subjects and the control group revealed some new insights that were previously undocumented. LASIK achieved high patient satisfaction, and factors associated with satisfaction were predictable, but sources of dissatisfaction were more idiosyncratic and contributing factors were identified.
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Zaune, Katharina. "Vergleichende Untersuchungen der Schnittdicke und Schnittqualität von LASIK-Mikrokeratomen." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-28024.
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Feltham, Mark Hayes Optometry & Vision Science Faculty of Science UNSW. "Factors which affect refractive outcome following LASIK for myopia." Awarded by:University of New South Wales. School of Optometry and Vision Science, 2004. http://handle.unsw.edu.au/1959.4/20800.
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Purpose: To improve the predictability, accuracy and stability of laser in-situ keratomileusis (LASIK), by evaluating the clinical, procedural and tissue response factors that affect refractive outcomes. Methods: Myopic LASIK surgeries (n=5,978) were carried out using the Technolas planoscan and Nidek EC-5000 excimer lasers. Clinical variables associated with a refractive outcome of within ??0.50 D of the target were identified using regression analysis. Possible procedural variations such as the timing of the procedure and accuracy of both the chosen keratome and excimer laser were evaluated. The predictability and accuracy of the ablation was assessed by measuring changes in corneal thickness during and after the procedure. Factors influencing the stability of refractive outcome were assessed. Results: Clinical factors associated with a refractive outcome of within ??0.50 D of the target included; corrections less than 5.00 DS (OR 0.21x, 95% CI 0.11-0.40x compared with corrections over -5.00 DS[referent]), patients younger than 40 years (patients over 50 OR 8.27x, 95% CI 3.41-20.03x, patients 40 to 50 years OR 1.93x, 95% CI 0.96-3.90x, compared with patients under 40[referent]) and average pre-operative curvatures between 43.50 and 45.50D (OR 0.39x, 95% CI 0.18-0.83 compared with curvatures of less than 43.50D [referent]). Refractive stability was improved using optic zone sizes between 5.5-6.0 mm, reduced myopic corrections, flatter pre-operative corneal curvatures and thicker corneal flaps (R??=25%, p<0.001). Procedural factors associated with poorer outcomes included: thinner measured flap thickness, deeper ablations and the use of the automated corneal shaper (ACS) microkeratome with a novice surgical team (R??=34%, p < 0.001). Delaying the ablation from 20 to 90 seconds (s) after flap lift was associated with a more stable refractive outcome at three months (p=0.017). In the 90 s following flap lift, the cornea thinned by 5??3%. The ablation rate per scan varied between procedures, however, the effect on refractive outcome was small (r=0.15, p=0.267). Changes in central corneal thickness indicated refractive stability (p=0.039). Conclusions: Applying the optimal clinical and procedural factors as described afforded a refractive outcome in a further 8% of cases, resulting in 94% to 96% of cases within ??0.50 DS of target. Refractive predictability was limited due to the inability of the keratome to produce a consistent corneal flap thickness and unexpected changes in corneal thickness. The accuracy of refractive outcome will decrease with larger ablations. The degree of refractive inaccuracy with high refractive corrections (> -10.00 D) can be over 1.00 D.
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Netto, Marcelo Vieira. "Efeitos do uso tópico da mitomicina C na prevenção e tratamento da opacidade corneana em coelhos submetidos à ceratectomia fotorrefrativa." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-20022009-132232/.
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Objetivos: Determinar os efeitos celulares e o mecanismo de ação da mitomicina C tópica na prevenção e tratamento da opacidade corneana em coelhos submetidos à ceratectomia fotorrefrativa (PRK). Métodos: Foram submetidos à cirurgia de PRK 224 coelhos para correção de -9 dioptrias esféricas, associada à aplicação de mitomicina C tópica ou solução salina balanceada. O nível de opacidade corneana foi avaliado por meio de análise à lâmpada de fenda. Os animais foram sacrificados quatro horas, 24 horas, quatro semanas e seis meses após a cirurgia. A análise imunohistoquímica foi realizada com as técnicas de TUNEL e foram utilizados os anticorpos Ki67 e alpha-SMA para a análise da apoptose celular, replicação celular e formação de miofibroblastos, respectivamente. Resultados: Todos os grupos submetidos à aplicação de mitomicina C apresentaram um maior número de células positivamente marcadas pelo ensaio com TUNEL (indicando maior taxa de apoptose celular) e um menor número de células positivamente marcadas pelo anticorpo Ki67 (indicando menor taxa de replicação celular). Uma menor quantidade de miofibroblastos (células positivamente marcadas pelo anticorpo alpha-SMA) foi identificada após a aplicação profilática da mitomicina C, comparada com sua aplicação com finalidade terapêutica. Além disso, identificou-se uma zona de acelularidade no estroma anterior de córneas tratadas com mitomicina C, persistente por um período mínimo de seis meses. Conclusões: A aplicação da mitomicina C diminuiu signficativamente a formação de opacidade corneana em coelhos. Apesar da mitomicina C ter induzido uma maior apoptose de ceratócitos e miofibroblastos, seu principal mecanismo de ação, responsável pela prevenção da opacidade corneana, decorreu do bloqueio da replicação dos ceratócitos ou outras linhagens celulares progenitoras dos miofibroblastos. A aplicação da mitomicina C na concentração de 0,002% mostrou-se tão eficiente quanto sua aplicação na concentração de 0,02%. Não obstante, uma persistente diminuição da densidade de ceratócitos no estroma anterior pode representar um sinal de alerta para possíveis complicações a longo prazoPurpose: To determine cellular effects and the mechanism through which topical mitomycin C prevents and treats corneal haze after photorefractive keratectomy (PRK) in rabbits. Methods: Minus nine diopters PRK with mitomycin C or balanced salt solution was performed in two hundred and twenty four New Zealand rabbits. Haze level was graded at the slit lamp. Rabbits were sacrificed at 4 hours, 24 hours, 4 weeks or 6 months after surgery and immunohistochemistry was performed with TUNEL assay, Ki67 and alpha-SMA to analyze keratocyte cells apoptosis, keratocyte cells replication and myofibroblast cells formation, respectively. Results: TUNEL-positive cells increased in all mitomycin C groups (representing more keratocyte cells undergoing apoptosis) while Ki67-positive cells decreased significanlty (representing a decreased keratocyte cells replication) following mitomycin C application. A greater decrease in myofibroblasts was noted with prophylactic mitomycin C treatment than therapeutic mitomycin C treatment. There was, however, an anterior stromal acellular zone in eyes treated with mitomycin C that persisted out to the maximum follow-up of 6 months. Conclusion: Mitomycin C application significantly reduced corneal haze formation in rabbits. Its treatment induces apoptosis of keratocytes and myofibroblasts, but the predominate effect in inhibiting or treating haze appears to be at the level of blocked replication of keratocytes or other progenitor cells of myofibroblasts. Treatment with 0.002% mitomycin C appears to be just as effective as higher concentrations (0.02%) in the rabbit model. However, a persistent decrease in keratocyte cells density in the anterior stroma could be a warning sign for future complications
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Goggin, Michael Joseph. "Outcome and complications of photorefractive keratectomy for myopia and astigmatism /." Title page, table of contents and aims only, 2003. http://web4.library.adelaide.edu.au/theses/09MS/09msg613.pdf.
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Scholtz, Sibylle [Verfasser]. "Vom Lesestein zur LASIK – die Geschichte der Sehhilfen / Sibylle Scholtz." Aachen : Shaker, 2006. http://d-nb.info/1170536530/34.
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Yilmaz, Seval. "Untersuchung von Hornhautoberfläche und Hornhautbrechkraft nach LASIK zur Behandlung der Hyperopie /." Frankfurt a.M, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000259459.
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Abahussin, Mohammad. "Study of corneal ultrastructure in normal and post-LASIK human eyes." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54709/.
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Laser
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Colling, Amber J. "A comparison of three methods of measuring central corneal thickness in normal and thinned corneas." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275058650.
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Puig, Galy Javier José. "Uso de biópticos (ICL y Lasik) para la corrección de la alta miopía." Doctoral thesis, Universitat Autònoma de Barcelona, 2001. http://hdl.handle.net/10803/4233.
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OBJETIVOS: Determinar la eficacia, predictibilidad, estabilidad y seguridad de la cirugía refractiva mediante "Biópticos" (combinación del implante de una lente fáquica de cámara posterior y láser in situ queratomileusis) en pacientes afectos de altas miopías.
Describir el procedimiento quirúrgico y mostrar los resultados visuales y refractivos del mismo.
MATERIAL Y MÉTODOS:
Hemos analizado 102 ojos de 63 pacientes afectos de alta miopía, intervenidos mediante el implante de una lente fáquica de cámara posterior tipo ICLTM y láser in situ queratomileusis (Lasik).
El seguimiento postoperatorio medio fue de 19 meses (rango: 12-36 meses).
RESULTADOS:
El equivalente esférico medio preoperatorio fue de -18,20 ± 4,21 D., con un astigmatismo medio asociado de -1,87 ± 1,57 D. La media aritmética del equivalente esférico tras implantar la lente fáquica y antes de realizar el Lasik fue de -2,59 ± 2,04 D. El equivalente esférico medio tras el procedimiento Bióptico completo resultó ser de -0,28 ± 0,33 D., con un cilindro medio de -0,53 ± 0,35 D.
El 100% de los pacientes se encontraban postoperatoriamente en el rango de ± 1,00 D. respecto a la emetropía, mientras el 95,09% lo hacían en el rango de ± 0,50 D.
Las refracciones postoperatorias se mantuvieron estables durante los sucesivos controles, sin cambios estadísticamente significativos.
La agudeza visual sin corrección mejoró en todos los casos. La agudeza visual corregida se mantuvo igual o mejoró postoperatoriamente en todos los casos excepto en dos. La media de ganancia de agudeza visual corregida postoperatoria fue de dos líneas de Snellen.
Todos los pacientes se mostraron muy satisfechos con los resultados obtenidos.
DISCUSIÓN:
El uso combinado de lentes fáquicas de cámara posterior tipo ICLTM y Láser in situ queratomileusis (Lasik) constituye un método efectivo y predecible para corregir la alta miopía.
Es frecuente la mejoría postoperatoria de la agudeza visual corregida de estos pacientes. Los resultados muestran una considerable seguridad del procedimiento a corto y medio plazo, así como una gran estabilidad refractiva.
PURPOSE:
To determine the efficacy, predictability, stability and safety of "Bioptics" refractive surgery (combined posterior chamber phakic intraocular lens implantation and laser in situ keratomileusis) in eyes with extreme myopia.
To report the technique and to assess the results (refraction and visual acuity) of this surgical procedure.
MATERIAL AND METHODS:
We analyzed the results of 102 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL (ICLTM) and also underwent secondary Lasik for the correction of extreme myopia.
Mean follow-up was 19 months after the Lasik procedure (range 12 to 36 months).
RESULTS:
Mean preoperative spherical equivalent refraction was -18,20 ± 4,21 D., and mean refractive cylinder was -1,87 ± 1,57 D. Mean spherical equivalent refraction after IOL implantation and before Lasik was -2,59 ± 2,04 D. Mean postoperative spherical equivalent refraction one year after the Lasik portion of the double Bioptics procedure was -0,28 ± 0,33 D., and mean refractive cylinder was -0,53 ± 0,35 D.
One hundred percent were within ± 1,00 D. and 95,09 % were within ± 0,50 D. of emmetropia at last examination.
The refractions remained stable with a statistically insignificant change during follow-up.
Uncorrected visual acuity improved in all cases. Best spectacle-corrected acuity remained the same or improved in all but two cases. Mean best spectacle-corrected acuity gain after the double procedure was two Snellen lines.
Patient satisfaction with the final visual outcome was very high.
CONCLUSIONS:
Combined posterior chamber phakic IOL implantation with ICLTM lens and Lasik (Bioptics) is an effective and reasonably predictable method for correcting high myopia.
Gains in spectacle-corrected visual acuity were common, and results demonstrated good short-medium term safety and refractive stability.
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Karlsson, Lydia. "En litteraturstudie om refraktiv kirurgi med fördjupning inom LASIK (Laser In Situ Keratomileusis)." Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19781.
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Syfte: Studiens syfte är att göra en kort redovisning av de vanligaste tekniker (LASIK, LASEK, PRK och RLE) som finns inom refraktiv kirurgi med en fördjupning inom LASIK (laser in situ keratomileusis). Studiens syfte är att ta reda på hur LASIK operationen går till, vilka som är lämpade kandidater och vilka de vanligaste riskerna som finns. Bakgrund: Keratorefraktiv kirurgi har utvecklats enormt under de senaste årtionden. De initiala försöken att korrigera sfärocylindriska refraktiva fel med corneal kirurgi och första generationen excimer laser kirurgi var effektiva för korrigering av lägre refraktiva fel. Utvecklingen av mer komplex laserteknologi har gett mer noggranna och förutsägbara resultat. Detta har gjort att indikationer för den refraktiva kirurgin har expanderat. LASIK har fått ett bra fäste inom den refraktiva kirurgin och används allt oftare med syftet att korrigera refraktiva fel. Metod: En litteraturstudie gjordes där fyra originalartiklar som presenterade resultat kopplade till ämnet studerades. Resultat: Excimer laserkirurgi är en effektiv metod för korrigering av sfärocylindriska refraktiva fel. En utveckling av mer komplex laserteknologi har resulterat i mer noggranna och förutsägbara resultat. De förbättrade resultaten beror även på att både den diagnostiska och den terapeutiska vågfrontteknologin lyfts fram. Slutsats: Sfäriska aberrationer visade sig vara mindre efter vågfrontoptimerad LASIK än efter kirurgi med konventionell LASIK. Inga bestående skillnader hittades mellan vågfrontstyrd PRK och vågfrontstyrd LASIK. Den vågfrontstyrda IntraLASIK visade inga fördelar på att bevara tårkvalité i jämförelse med de konventionella IntraLASIK.
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Lam, Wing-wah Phoebe. "A systematic review of postoperative treatments for laser eye surgery." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25549686.
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Wallau, Anelise Dutra [UNIFESP]. "Análise dos resultados de ceratectomia fotorrefrativa com mitomicina C e LASIK para correção miópica." Universidade Federal de São Paulo (UNIFESP), 2010. http://repositorio.unifesp.br/handle/11600/8934.
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Publico-026d.pdf: 895113 bytes, checksum: 37de279e78fead2b9aa3c17fd44ab0f0 (MD5)Objetivos: Comparar os resultados de acuidade visual, refração estática, aberrometria e sensibilidade ao contraste em olhos com miopia moderada submetidos à ceratectomia fotorrefrativa (PRK) com mitomicina C (MMC) ou à ceratomileuse assistida por excimer laser in situ (LASIK) em cirurgias guiadas por frente de onda durante acompanhamento de um ano. Avaliar o aspecto biomicroscópico nos dois grupos durante seguimento. Avaliar subjetivamente percepção de dor, queixas visuais e satisfação com resultado cirúrgico nos dois grupos durante acompanhamento. Analisar índices de microscopia especular nos dois grupos antes e seis meses após cirurgia. Comparar propriedades biomecânicas da córnea nos dois grupos um ano após o procedimento cirúrgico. Métodos: Quarenta e quatro pacientes (88 olhos) com miopia moderada e cálculo de consumo corneano maior que 50 μm na plataforma LADARWave 4000 (Alcon) em ambos os olhos foram selecionados para receber aleatoriamente LASIK em um olho e PRK com aplicação de MMC 0,002% durante um minuto no olho contralateral em cirurgias guiadas por frente de onda. Topografia corneana (EyeSys 2000, EyeSys e Orbscan II, Orbtek/Bausch & Lomb), acuidade visual sem correção (AVSC, tabela Early Treatment Diabetic Retinopaty Study), refração estática, acuidade visual com correção (AVCC), aberrometria (LADARWave 4000), paquimetria ultrassônica corneana central (Sonogage) e exame oftalmológico completo foram realizados no pré-operatório e no seguimento de um, três, seis e doze meses pós-operatório. Sensibilidade ao contraste fotópica e mesópica (Optec 6500, F.A.C.T.; Stereo Optical) com correção foram realizadas nos dois olhos antes da cirurgia e três, seis e doze meses após. Questionário subjetivo de dor foi aplicado no pós-operatório recente, e questionário de sintomas visuais e satisfação com o procedimento em cada olho foi aplicado nas visitas de acompanhamento com um, três, seis e doze meses de pós-operatório. Biomicroscopia de segmento anterior foi realizada no período pós-operatório recente e nas visitas de acompanhamento sempre como último exame do dia (examinador mascarado para procedimento cirúrgico). Microscopia especular (Topcon SP 2000p) foi realizada antes e seis meses após cirurgia. Avaliação biomecânica da córnea (ORA, Reichert) foi realizada um ano após o procedimento cirúrgico. Os testes ANOVA para medidas repetidas e t de student foram utilizados para análise estatística. Resultados: A média de idade dos pacientes do estudo foi de 31,7 anos (variou entre 21 e 54 anos). Não houve diferença significativa entre os grupos antes da cirurgia quanto a AVSC, AVCC, aberrometria, sensibilidade ao contraste ou microscopia especular. O equivalente esférico (EE) médio programado nos olhos que receberam LASIK foi de - 3,99±1,20 dioptrias (D) e de - 3,85±1,12 D nos olhos que receberam PRK com MMC (p>0,05). A profundidade de ablação média foi de 73,09±14,55 μm e 70,70±14,07 μm, no grupo LASIK e no grupo PRK com MMC, respectivamente (p>0,05). Quarenta e dois pacientes (95,5%) completaram um ano de acompanhamento. Os olhos que receberam PRK com MMC apresentaram média de AVSC significativamente superior aos olhos que receberam LASIK com três, seis e doze meses de pós-operatório. A média de AVCC também foi estatisticamente superior no grupo PRK com MMC na visita de um ano de pós-operatório (p<0,05). Não houve diferença estatística entre os grupos quanto ao EE ao longo do acompanhamento. Todos os olhos que receberam PRK com MMC completaram a reepitelização corneana em até cinco dias após o procedimento, e nenhum olho apresentou haze maior que grau 1 (escala de Fantes). Os olhos que receberam LASIK apresentaram valores de aberrações de baixa e alta ordem estatisticamente superiores aos olhos que receberam PRK com MMC durante todo o acompanhamento (p<0.05). Os olhos que receberam PRK com MMC obtiveram desempenho superior no teste de sensibilidade ao contraste em condições fotópicas e mesópicas quando comparados ao grupo LASIK durante seguimento (p<0,05). Até o quinto dia de pós-operatório, o grupo PRK com MMC apresentou índices de dor superiores ao grupo LASIK. O grupo PRK com MMC foi melhor avaliado no questionário subjetivo de queixas visuais e satisfação cirúrgica. Não houve diferença estatística entre os grupos quanto à microscopia especular (p>0,05). Na avaliação biomecânica da córnea, o grupo LASIK apresentou valores de fator de resistência corneana (CRF) e histerese (CH) significativamente superiores ao grupo PRK com MMC (p<0,05). Conclusões: Os olhos que receberam PRK com MMC apresentaram melhores valores de AVSC e AVCC, melhor correção de aberrações de baixa ordem e menores valores de aberrações de alta ordem em relação aos olhos que receberam LASIK. O grupo PRK com MMC também apresentou valores superiores de sensibilidade ao contraste e foi melhor avaliado em questionário subjetivo de satisfação cirúrgica. Não houve presença de haze clinicamente significativo no grupo PRK com MMC. O grupo PRK com MMC apresentou maiores índices de dor no período pósoperatório recente. Não houve diferença entre os índices de microscopia especular nos dois grupos. O grupo LASIK apresentou índices superiores de CRF e CH.
Purpose: To compare visual acuity results, cycloplegic refraction, aberrometry and contrast sensitivity in eyes that underwent photorefractive keratectomy (PRK) with mitomycin C (MMC) or laser in situ keratomileusis (LASIK) for wavefront-guided myopic corrections during one year follow-up. To evaluate slit-lamp microscopy in both groups during follow-up. To evaluate subjective pain, visual complains and satisfaction with visual results in the two groups during follow-up. To analyse specular microscopy values before and six months after surgeries in both groups. To compare biomechanical properties of the cornea in the two groups one year after surgeries. Methods: Forty-four patients (88 eyes) with moderate myopia and an estimated ablation depth greater than 50 μm using the LADARWave 4000 (Alcon Laboratories) platform in both eyes were randomized to receive LASIK in one eye and PRK with application of MMC 0.002% for one minute in the fellow eye in wavefront-guided surgeries. Corneal topography (EyeSys 2000, EyeSys and Orbscan II, Orbtek/Bausch & Lomb), uncorrected visual acuity (UCVA, Early Treatment Diabetic Retinopaty Study table), cycloplegic refraction, best spectacle-corrected visual acuity (BSCVA), aberrometry (LADARWave 4000), central ultrasound corneal pachymetry (Sonogage Inc) and a comprehensive ophthalmologic examination were performed before surgeries and at one, three, six and twelve months postoperative visits. Photopic and mesopic contrast sensitivity (Optec 6500, F.A.C.T.; Stereo Optical Co) with BSCVA was performed in both eyes before surgeries and at three, six and 12 months follow-up. A subjective pain questionnaire was applied at early postoperative visits and another visual complain and satisfaction questionnaire with surgery in each eye was applied one, three, six and twelve months after surgical procedures. Slit-lamp anterior segment microscopy was performed at early postoperative visits and at follow-up visits always as the last examination (blind examiner for surgical procedure). Specular microscopy (Topcon SP 2000p, Topcon) was performed before and six months after surgeries. Biomechanical properties of the cornea (ORA, Reichert) were evaluated one year after surgeries. The tests ANOVA for repeated measures and the student’s t test were used for statistical analyses. Results: The mean age was 31.7 years (range, 21-54 years). There was no statistically significant between-group difference in UCVA, BSCVA, aberrometry, contrast sensitivity or specular microscopy before surgeries. The mean attempted spherical equivalent (SE) was - 3.99±1.20 diopters (D) in LASIK eyes and - 3.85±1.12 D in PRK with MMC eyes (p>0.05). The mean ablation depth was 73.09±14.55 μm and 70.70±14.07 μm in LASIK and PRK with MMC eyes, respectively (p>0.05). Forty-two patients (95.5%) completed one year follow-up. The PRK with MMC eyes presented statistically significant better mean UCVA values than LASIK eyes at three, six and 12 months visits. The mean BSCVA was also statistically significant better in PRK with MMC eyes than in LASIK eyes one year after surgeries (p<0.05). There was no between-groups statistical difference in SE during one year follow-up. All PRK with MMC eyes reepithelialized within five days after surgical procedure and no eye presented more than grade 1 haze (Fantes scale). The LASIK eyes presented statistically significant higher lower and higher order aberrations values than PRK with MMC eyes during follow-up (p<0.05). The PRK with MMC group showed better results in photopic and mesopic contrast sensitivity than LASIK eyes during one year follow-up (p<0.05). Until the fifth postoperative day, PRK with MMC eyes presented higher pain scores than LASIK eyes. PRK with MMC eyes were better rated in terms of subjective visual symptoms and visual satisfaction. There were no statistical differences between the groups in specular microscopy (p>0.05). LASIK eyes showed statistically significant higher corneal resistance factor (CRF) and corneal hysteresis (CH) values than PRK with MMC eyes (p<0.05). Conclusions: The PRK with MMC eyes presented better UCVA, BSCVA, better correction of lower order aberrations and lower higher order aberration values than LASIK eyes. It also showed better contrast sensitivity results and was better rated in terms of visual satisfaction. There was no clinically significant haze in PRK with MMC eyes. The PRK with MMC eyes presented higher pain scores at early postoperative visits. There was no between groups differences in specular microscopy. LASIK eyes presented higher CRF and CH values one year after surgeries.
TEDE
BV UNIFESP: Teses e dissertações
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Salah-Mabed, Imène. "Descriptions anatomiques et méthodologiques aux fins d'optimisation de techniques de chirurgie cornéenne à visée réfractive." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS164/document.
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Dans un contexte d’augmentation du nombre d’amétropes dans la population mondiale, et en conséquence, de l’accroissement du recours aux techniques de corrections chirurgicales, la compréhension et l’amélioration de celles-ci sont un enjeu crucial. Nous avons cherché à améliorer la prédictibilité de certains résultats postopératoires dans le cas d’un LASIK (Laser-Assisted In-Situ Keratomileusis), d’une PKR (Photorefractive Keratectomy) ou d'une chirurgie de la cataracte, et ainsi formuler des recommandations pratiques qui contribueraient au développement de stratégies de traitement davantage personnalisés. Pour cela, nous avons utilisé prospectivement des méthodologies de « contrôle de qualité » des chirurgies sur de larges échantillons de patients. Dans un premier temps, nous avons étudié la dynamique pupillaire dans le cadre de chirurgies au LASIK et notamment le rôle du centre pupillaire, point de référence important dans les stratégies de centrage. Nous avons également évalué la dynamique du diamètre pupillaire et les modifications du segment antérieur sur des yeux subissant une chirurgie de la cataracte. La seconde partie du travail s’est focalisée sur le rôle de l’épithélium dans la topographique cornéenne. Nous avons comparé les topographies spéculaires de l'épithélium et de la couche de Bowman sur des cornées saines et des cornées kératoconiques, présentant une myopie faible à modérée corrigée par PKR. Enfin, dans la dernière partie de notre recherche, nous nous sommes intéressés aux changements de paramètres anatomiques de l'oeil, des performances visuelles et de la qualité de vision subjective survenant dans un échantillon d’yeux myopes après un LASIK réalisé avec le laser WaveLight® Refractive Suite (Alcon® Laboratories Inc., USA)While the number of ametropic eyes in the world’s population and consequently the use of surgical correction techniques is increasing, understanding and improving these techniques is a crucial issue. We sought to improve the predictability of certain postoperative results in the case of LASIK (Laser-Assisted In-Situ Keratomileusis), PRK (Photorefractive Keratectomy) and cataract surgery, and thus to formulate practical recommendations that would contribute to the development of more personalized treatment strategies. To achieve this objective, we have prospectively used "quality control" methodologies to assess surgeries performed on large samples of patients. First, we studied the pupillary dynamics in LASIK surgery and in particular the role of the pupillary centre, an important point of reference in the centration strategies. We also assessed the dynamics of pupillary diameter and anterior segment changes on eyes undergoing cataract surgery. The second part of the work focused on the role of the epithelium in the corneal topography. We compared specular topographies of the epithelium and Bowman's layer in healthy and keratoconus corneas with mild to moderate myopia corrected by PRK. Finally, in the last part of our research, we were interested in the changes in anatomical parameters of the eye, visual performance and subjective quality of vision occurring in a sample of myopic eyes after LASIK performed with the WaveLight® Refractive Suite (Alcon® Laboratories Inc., USA)
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Moshirfar, Majid, Tirth Shah, David Skanchy, Steven Linn, Paul Kang, and Daniel Durrie. "Comparison and analysis of FDA reported visual outcomes of the three latest platforms for LASIK: wavefront guided Visx iDesign, topography guided WaveLight Allegro Contoura, and topography guided Nidek EC-5000 CATz." DOVE MEDICAL PRESS LTD, 2017. http://hdl.handle.net/10150/622646.
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Purpose: To compare and analyze the differences in visual outcomes between Visx iDesign Advanced WaveScan Studio (TM) System, Alcon Wavelight Allegro Topolyzer and Nidek EC-5000 using Final Fit (TM) Custom Ablation Treatment Software from the submitted summary of safety and effectiveness of the US Food and Drug Administration (FDA) data. Methods: In this retrospective comparative study, 334 eyes from Visx iDesign, 212 eyes from Alcon Contour, and 135 eyes from Nidek CATz platforms were analyzed for primary and secondary visual outcomes. These outcomes were compared via side-by-side graphical and tabular representation of the FDA data. Statistical significance was calculated when appropriate to assess differences. A P-value <0.05 was considered statistically significant. Results: The mean postoperative uncorrected distance visual acuity (UDVA) at 12 months was 20/19.25 +/- 8.76, 20/16.59 +/- 5.94, and 20/19.17 +/- 4.46 for Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. In at least 90% of treated eyes at 3 months and 12 months, all three lasers showed either no change or a gain of corrected distance visual acuity (CDVA). Mesopic contrast sensitivity at 6 months showed a clinically significant increase of 41.3%, 25.1%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. Photopic contrast sensitivity at 6 months showed a clinically significant increase of 19.2%, 31.9%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. Conclusion: FDA data for the three platforms shows all three were excellent with respect to efficacy, safety, accuracy, and stability. However, there are some differences between the platforms with certain outcome measurements. Overall, patients using all three lasers showed significant improvements in primary and secondary visual outcomes after LASIK surgery.
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Kaszynski, Elizabeth. "The Myth of Emmetropia: Perception in Rhetorical Studies." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149616/.
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This thesis sets up the problem of sight in a visual society, with the aim to answer how the visual makes itself known. The conversation starts on visuality, and where there are gaps in understanding. The first of two case studies examines the absence of sight, or blindness, both literal and figurative. Through a study of blind photographers and their work, this chapter examines the nature of perception, and how biological blindness may influence and inform our understanding of figurative blindness. The second case study examines what the improvement of damaged sight has to say about the rhetorical nature of images. This chapter examines various means of improving sight, using literal improvements to sight to understand figurative improvements in vision and perception. The fourth and final chapter seeks to sum up what has been discovered about the rhetorical nature of sight through the ends of the spectrum of sight.
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Aakre, Bente Monica. "Longitudinal assessments of corneal and tear film characteristics after lasik versus continued contact lens wear." Thesis, Glasgow Caledonian University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517930.
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Changes in oxygen availability, exerted mechanical force or even surgical manipulation are all factors known to influence corneal characteristics, yet detailed information about the changes such influence may induce is limited in ophthalmic literature. Furthermore, the appearance of the corneal endothelium, which is often used as a presage of structural and functional changes taking place in the cornea, has not been systematically studied over extended periods and information such as endothelial morphometry is hence not available. The purpose of this study was therefore to evaluate the endothelial morphometry over a two-year period in subjects who underwent different types of intervention, either in the form of change in contact lens material, LASIK surgery or by replacing existing contact lenses with a similar type. A group of spectacle wearers served as a control group. Results obtained through the course of the study revealed that subjects who continued wearing conventional contact lenses had substantial amounts of polymegethism compared with the control group. Those who had undergone LASIK surgery had significantly reduced amount of polymegethism three months after surgery and reached a concentration level that was consistent with the control group after 24 months. A similar tendency was found in the subjects who were refitted with silicone-hydrogel (SiH) lenses although the high number of endothelial cells that was found to reverse back to a six-sided shape after LASIK treatment was not apparent in this group of subjects. This may be associated with the sustained inflammatory response, which is arguably present in the corneas of these subjects. LASIK surgery seems to have no detrimental effect on the corneal endothelium and the procedure may even reverse some of the contact lens induced changes in the endothelial mosaic. Pre-ocular tear film evaluation revealed no inferior quality or quantity nor did these subjects report any higher dry eye sensation than the other subjects.
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Lazaridis, Apostolos [Verfasser], and Walter [Akademischer Betreuer] Sekundo. "Topographic analysis of the centration of the treatment zone after Small Incision Lenticule Extraction (SMILE) surgery for myopia and myopic astigmatism and comparison to Femtosecond laser-assisted LASIK (FS-LASIK) / Apostolos Lazaridis ; Betreuer: Walter Sekundo." Marburg : Philipps-Universität Marburg, 2018. http://d-nb.info/1173322426/34.
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Vázquez, Barrero Mercedes. "Implante de lente intraocular (LIO) jáquica de sujeción iridiana vs. cirugía combinada: (Implante de LIO jáquica de sujeción iridiana y grulatomileusis in situ asistida por láser (LASIK) para corrección de miopía alta." Doctoral thesis, Universitat Autònoma de Barcelona, 2003. http://hdl.handle.net/10803/4257.
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Actualmente uno de los principales objetivos en cirugía refractiva no es sólo la emetropía, sino obtener una alta calidad de visión, parámetro de difícil cuantificación al estar involucrada la subjetividad del paciente. Para obtener un buen resultado postoperatorio es necesario que la zona óptica del procedimiento a realizar sea amplia. Por otro lado, a medida que aumenta el defecto refractivo a corregir esta zona óptica debe ser disminuida por razones de seguridad. Es por ello que han hecho su aparición los procedimientos combinados, generalmente uno corneal y otro intraocular; al utilizarse la zona óptica más grande posible en ambos se mejora por una parte, la calidad de visión en condiciones de baja iluminación y por otra, disminuyen quejas frecuentes como el deslumbramiento y los halos en pacientes con miopías altas.
En el presente estudio prospectivo, longitudinal y aleatorizado se muestra una serie de casos de pacientes afectos de miopía alta con equivalentes esféricos superiores a -15.50 D. En un grupo de estos pacientes se empleó una técnica combinada, una corneal (LASIK) y otra intraocular (implante de lente fáquica de Artisan®) para mantener una zona óptica de tratamiento de 6 mm. Este grupo de pacientes se comparó con otro de iguales características en los que se empleó una sola técnica, el implante de lente fáquica de Artisan®, con una zona óptica de 5 mm. Se valoró la respuesta clínica objetiva mediante la medición de la agudeza visual sin y con corrección, refracción manifiesta y sensibilidad al contraste, la respuesta clínica subjetiva medida a través de cuestionarios subjetivos, la predictibilidad, seguridad y estabilidad de ambos métodos.
La respuesta clínica objetiva y subjetiva, así como la predictibilidad del método combinado (implantación de LIO Artisan" más LASIK) fue mejor que la del método único (implantación de LIO Artisan"), por lo que se concluye que el método combinado es más eficaz y predecible que el método único. Todo esto nos hace inferir que la zona óptica de 6 mm es muy importante y determinante en las diferencias presentadas entre los dos grupos. Indudablemente, otros factores también influyen los resultados como, por ejemplo, el buen centramiento de la lente, factor que depende de la habilidad del cirujano en el caso de la lente Artisan".
No se observaron diferencias estadísticamente significativas entre ambos métodos tomando en cuenta los criterios de seguridad y estabilidad ya establecidos en cirugía refractiva, durante el primer año de postoperatorio.
El concepto de satisfacción del paciente es un punto muy importante que también debe examinarse en aquellos pacientes sometidos a cualquier tipo de cirugía refractiva. Las principales fuentes de insatisfacción son los halos, deslumbramiento y alteraciones en la visión nocturna, especialmente cuando se efectúa cirugía refractiva con zona óptica pequeña. En este sentido, la agudeza visual y la refracción postoperatoria no son parámetros suficientes para juzgar los resultados obtenidos. La auto-evaluación por parte del paciente así como pruebas funcionales del tipo de sensibilidad al contraste o medición de las aberraciones ópticas son también necesarias para la valoración integral de nuestros pacientes.
Currently one of the main objectives in refractive surgery it is not emetropia but high quality of vision, which is difficult to evaluate because of the patients subjectivity.
It is necessary to use a wide optical zone in order to obtain a high-quality postoperative result. On the other hand, when the refractive error increases, the optical zone must be reduced for safety reasons. For this rationale, combined procedures have emerged, usually one corneal and other intraocular, to improve the quality of vision in dim illumination conditions and diminish frequent complaints such as glare and halos in high myopic patients, when the widest optical zone is used in both procedures.
The current prospective, longitudinal and randomized study shows a series of cases of high myopic patients with spherical equivalents higher than -15.50 diopters. In one group of these patients a combined technique was used, one corneal, LASIK, and other intraocular, phakic Artisan® intraocular lens (IOL)implantation, in order to maintain a 6 mm optical zone. This group of patients was matched up to another group with equal characteristics submitted to 5 mm phakic Artisan® IOL implantation. The assessment included the objective response evaluated by visual acuity with/without correction, manifest refraction, and contrast sensitivity while subjective response was evaluated by questionnaires. Moreover, predictability, safety and stability of both methods were measured and compared.
The objective and subjective responses as well as the predictability of the combined method (Artisan® lens implantation plus LASIK) were better than those in the unique method (Artisan® lens implantation), consequently the combined method is more efficient and predictable than the unique method. All of this rationale let us infer that the 6 mm optical zone is very important and determinant in the differences between the two groups. Nevertheless, other factors such as a well-centred IOL, influence the final result, issue that depends on surgeon's skill.
There were no statistically significant differences between both groups considering safety and stability criteria, already established in refractive surgery, during the first postoperative year.
Patient's satisfaction concept is a very important subject that must be check up in those patients submitted to any refractive surgery. The main source of unsatisfied patients are halos, glare and night vision alterations, especially in those cases submitted to procedures with small optical zone. Therefore, postoperative visual acuity and refraction are not the only parameters to take into account in results assessment. Patient's self-evaluation and functional tests such as contrast sensitivity or optical aberration measurement are necessary to achieve a complete evaluation.
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Gatell, Tortajada Jordi. "Tratamiento personalizado de la miopía." Doctoral thesis, Universitat Autònoma de Barcelona, 2002. http://hdl.handle.net/10803/4260.
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Introducción: Se ha realizado un estudio comparativo entre el tratamiento LASIK estándar, y el tratamiento personalizado de la miopía basado en la aberrometría. La diferencia principal entre los dos tratamientos es el patrón de ablación, siendo en el tratamiento personalizado un patrón asférico. Con éste se pretende conseguir una mejor calidad visual postoperatoria en los pacientes operados de cirugía refractiva.
Material y métodos:
Se ha dividido la población en dos grupos homogéneos en cuanto a miopía, edad, sexo, y aberraciones preoperatorias. A cada grupo se le ha tratado con un laser diferente, y se les ha comparado en términos de predictibilidad, eficacia, seguridad y estabilidad. Además se les ha realizado un seguimiento postoperatorio de la evolución de las aberraciones para determinar las diferencias en la corrección de éstas entre los dos laseres. Se ha utilizado un aberrómetro basado en el método de Hartmann-Shack, y un topógrafo de elevación. Junto a esto se ha determinado el cambio inducido en la sensibilidad al contraste debido a la cirugía mediante la caja de Ginsburg. Por ultimo hemos comparado los dos láseres en términos de paquimetría y cantidad de ablación, y zona óptica. La aplicación del laser se ha realizado con un Technolas 217Z, que incorpora la posibilidad de tratamiento LASIK estándar, o personalizado, con las novedades del haz de 1mm y con perfil gausiano truncado.
Resultados:
La predictibilidad, eficacia, seguridad y estabilidad han sido similares en ambos laseres aunque el tratamiento personalizado consigue mejores resultados en cuanto a seguridad, ya que algunos pacientes pueden llegar a ganar hasta 2 líneas de visión, lo que no hemos podido apreciar con el tratamiento estándar. En cuanto a las aberraciones, el tratamiento personalizado ha conseguido reducir, o en algunos casos inducir en menor grado aberraciones de tercer y cuarto orden. En lo que se refiere a la sensibilidad al contraste, con el tratamiento personalizado se consigue conservar ésta en las altas frecuencias. Otro resultado interesante ha sido que el tratamiento personalizado de la miopía ablaciona un 30% menos de tejido de media, debido al patrón de ablación asférico que le permite reducir la zona de transición, razón por la cual las zonas ópticas del tratamiento personalizado son menores.
Conclusiones:
Los resultados obtenidos son esperanzadores, ya que el tratamiento personalizado ha demostrado ventajas respecto al tratamiento estándar, y nos animan a seguir la investigación en esta dirección. Debemos tener en cuenta que estamos en los albores de esta nueva tecnología y que nos falta mucho por descubrir para poder poner a la práctica todo lo que ésta nos puede aportar.
Introduction:
We have compared standard LASIK treatment with customized ablation based on aberrometry. The main difference between these two treatments is the ablation pattern, as in customized ablation this pattern is aspheric. This way, we aim to a better postoperatively visual quality in patients who have undergone corneal refractive surgery.
Materials and methods:
We have split the population into two homogeneous groups in terms of myopia, age, sex and preoperative aberrations. Each group was treated with a different laser and were compared in terms of predictability, efficacy, security and stability. Moreover we carried on a postoperative follow-up of the aberrations evolution so as to define the difference between the two lasers. We used an aberrometer based on Hartmann-Shack technology, and elevation topography. We also determined the change in contrast sensitivity induced by the surgery with the Ginsburg box. Finally, we compared the two lasers in terms of paquimetry and depth of ablation, and optical zone. Laser delivery has been done with a Technolas 217Z, which can ablate in a standard or a customized way, as it introduces new technology as the 1mm spot or the truncated gausian beam.
Results:
Predictability, efficacy, security and stability were similar in both lasers,
although the customized treatment achieves better results in terms of
security, as some patients can gain two lines of vision, contrary to the results obtains with standard LASIK. About the performance in the correction of aberrations, customized ablation has reduced or induced in a smaller way, third and fourth order aberrations. About contrast sensitivity, customized ablation allows not to lose contrast sensitivity in higher frequencies. Another interesting result is that customized ablation ablates 30% less tissue due to its aspheric ablation pattern which allows a reduction in the transition zone, reason why the optical zone in customized ablations are smaller than in standard treatments.
Conclusions:
Results obtained are encouraging, as customized ablations has shown advantages with respect to standard LASIK and this gives us reasons to going on investigating in this new and promising technology. We have to bear in mind that we are in the very beginning of this new technology and we have a long way to go in order to put into practice all this technology can offer to us.
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Bailey, Melissa D. "The assessment of postoperative refractive surgery patients in clinical research." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1086104689.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2004.Document formatted into pages; contains 137 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 June 1.
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Cuadrado, Escamilla José Luís. "Estudio anatomo-clínico y epidemiológico de la queratitis laminar difusa como complicación postquirurgica de la fotoqueratomileusis (LASIK)." Doctoral thesis, Universitat de València, 2008. http://hdl.handle.net/10803/9478.
Full textAbstract:
OBJETIVOS La presente Thesis Doctoralis se propone como objetivo principal estudiar laincidencia de queratitis laminar difusa (DLK) en pacientes amétropes tratados mediante cirugíaquerato-refractiva (LASIK). Pretende, además, analizar las variables preoperatoriasrelacionadas con el desarrollo de esta complicación así como sus característicasepidemiológicas y clínicas, a partir de una muestra de 488 ojos. Paralelamente, se estudiadicha intervención quirúrgica y complicación postoperatoria desde un punto de vistamorfológico.MATERIAL Y METODOS La metodología utilizada en la Tesis ha sido codificar 78 variables(cuantitativas y cualitativas) para la caracterización clínica y epidemiológica de los pacientes,tanto antes como después del acto quirúrgico. A partir de los 38.064 datos obtenidos, seefectúa un estudio estadístico descriptivo y se aplican análisis bivariantes y de regresiónlogística para determinar las variables preoperatorias relacionadas con el desarrollo de estapatología (programas informáticos OFTALMO-DSM y SPSS v 11.0 for Windows).RESULTADOS Los resultados obtenidos permiten conocer con más detalle los factores que, enla muestra analizada, tienen una relación estadísticamente significativa con la aparición dequeratitis laminar difusa postquirúrgica, así como la distribución de sus diferentes tipos ygrados. La Tesis ofrece parámetros objetivos de la incidencia de esta patología que puedencompararse con los registrados en otros centros nacionales e internacionales y eventualmenteser la base para ensayos de nuevas técnicas dirigidas a su prevención.CONCLUSIONES (1) La incidencia de la queratitis laminar difusa en este estudio fue del 9.8%con un intervalo de confianza del 95% (7.16 - 12.43). (2) El perfil clínico del pacientediagnosticado de queratitis laminar difusa es asintomático, siendo el infiltrado corneal periféricoen la entrecara el hallazgo clínico más frecuente, generalmente de aparición en el primer díapostquirúrgico. (3) Clasificando la queratitis laminar difusa el grado más frecuente fue el gradoI, con una incidencia del 4.9% (intervalo de confianza del 95%: 2.98 - 6.81). Según lapresentación, la queratitis laminar difusa epidémica tiene una frecuencia del 5.7% (intervalo deconfianza del 95%: 3.64 - 7.75). (4) La hipermetropía, la edad y la intolerancia a lentes decontacto fueron las variables asociadas estadísticamente a la aparición de queratitis laminardifusa tras la regresión logística. El diámetro pupilar mesópico quedó en el límite designificación estadística. (5) El vocablo latino más apropiado para referirnos a la cirugía LASIKes el de "Foto-Queratomileusis". (6) Los ojos intervenidos de cirugía refractiva mediante Foto-Queratomileusis presentan una cavidad virtual intracorneal que modifica sus característicasanatomo-funcionales. La queratitis laminar difusa es una manifestación de dicho cambiofisiopatogénico.The main objective of this Thesis Doctoralis is to study the incidence of DLK inametrope patients treated with kerato-refractive surgery (LASIK). In addition, preoperativefactors related with this complication are studied, as well as its clinical and epidemiologicalcharacteristics, after the analysis of a sample of 488 eyes. The aforementioned surgicalprocedure and the postoperative complication are also studied from a morphologicalperspective.The methodology comprised the evaluaction of 78 quantitative and qualitative variablesfor the clinical and epidemiological characterization of the patients, before and after surgery.38.064 items were obtained, that underwent statistical descriptive analysis. Logistic regressionand bivariate analysis were performed as to determine the preoperative variables associatedwith the development of this entity.The results obtained led us to know in detail the many factors that, in the sampleanalyzed, had a statistically signinficant association with the development of postoperative DLK,as well as the distribution of its different types and grades. This Thesis provides objectiveparameters of the incidence of this entity, that may be compared with those obtained in othernational or international centers, and may in the future offer a rationale for the introduction ofnew preventing strategies.Conclusions: (1) the incidence of diffuse lamellar keratitis in this study was 9,8%, with a95% confidence interval: 7,16-12,439. (2) Most patients diagnosed with DLK wereasymptomatic. The most frequent clinical finding was peripheral corneal infiltrates in theinterface, that mostly evolved within the first day after surgery. (3) After the classification, themost frequent DLK subtype was grade I, with an incidence of 4,9% (95% confidence interval:2,98-6,81). Depending on presentation, epidemic diffuse lamellar keratitis has a frequency of5,7% (95% confidence interval: 3,64-7,75). (4) After logistic regression, variables that showed astatistically significant association were: hyperopia, age and intollerance to contact lenses. Themesopic pupil diameter was at the limit of statistic significance. (5) After LASIK, the operatedeye has a virtual intracorneal cavity that modifies its anatomo-functional properties. DLK is amanifestation of this physiopathological changes.
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Haque, Sameena. "In Vivo Imaging of Corneal Conditions using Optical Coherence Tomography." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2976.
Full textAbstract:
Purposes: To use optical coherence tomography (OCT) to image and quantify the effect of various corneal conditions, in terms of corneal, stromal and epithelial thickness, and light backscatter. To assess the changes caused by overnight orthokeratology (Corneal Refractive Therapy; CRTTM) lens wear, keratoconus and laser in-situ keratomileusis (LASIK) refractive surgery, each of which may lead to topographical alterations in corneal thickness either by temporary moulding, degeneration, or permanent laser ablation, respectively. Methods: Topographical thickness of the cornea was measured using OCT in all studies. The CRTTM studies investigated myopic and hyperopic treatment, throughout the day. The myopic studies followed lens wear over a 4 week period, which was extended to 12 months, and investigated the thickness changes produced by two lenses of different oxygen transmissibility. CRTTM for hyperopia (CRTHTM) was evaluated after a single night of lens wear.
In the investigation of keratoconus, OCT corneal thickness values were compared to those obtained from Orbscan II (ORB) and ultrasound pachymetry (UP). A new fixation device was constructed to aid in the measurement of topographical corneal and epithelial thickness along 8 directions of gaze. Pachymetry maps were produced for the normal non-lens wearing cornea, and compared with the rigid gas permeable (RGP) lens wearing cornea and the keratoconic cornea.
Thickness changes prior to, and following LASIK were measured and monitored throughout six months. Myopic and hyperopic correction was investigated individually, as the laser ablation profiles differ for each type of procedure. The LASIK flap interface was also evaluated by using light backscatter data to monitor healing.
Results: Following immediate lens removal after myopic CRTTM, the central cornea swelled less than the periphery, with corneal swelling recovering to baseline levels within 3 hours. The central epithelium decreased and mid-peripheral epithelium increased in thickness, with a more gradual recovery throughout the day. There also seemed to be an adaptation effect on the cornea and epithelium, showing a reduced amount of change by the end of the 4 week study period. The thickness changes did not alter dramatically during the 12 month extended study. In comparing the two lens materials used for myopic CRTTM (Dk/t 91 vs. 47), there were differences in stromal swelling, but no differences in the central epithelial thinning caused by lens wear. There was a statistically insignificant asymmetry in mid-peripheral epithelial thickening between eyes, with the lens of lower Dk causing the greater amount of thickening. Hyperopic CRTTM produced a greater increase in central stromal and central epithelial thickness than the mid-periphery. Once again, the stroma recovered faster than the epithelium, which remained significantly thicker centrally for at least six hours following lens removal.
Global pachymetry measurements of the normal cornea and epithelium found the periphery to be thicker than the centre. The superior cornea and epithelium was thicker than the inferior. In the measurement of the keratoconic cornea, OCT and ORB correlated well in corneal thickness values. UP measured greater values of corneal thickness. The keratoconic epithelium was thinner than normal, and more so over the apex of the cone than at the centre. The location of the cone was most commonly found in the inferior temporal region. Central epithelial thickness was thinner in keratoconics than in RGP lens wearers, which in turn was thinner than in non-lens wearers.
Following LASIK surgery for both myopia and hyperopia, the topographical OCT thickness profiles showed stromal thinning in the areas of ablation. The central myopic cornea showed slight regression at 6 months. During early recovery, epithelial thickness increased centrally in hyperopes and mid-peripherally in myopes. By the end of the 6 month study, mid-peripheral epithelial thickness was greater than the centre in both groups of subjects. The light backscatter profiles after LASIK showed a greater increase in backscatter on the anterior side of the flap interface (nearer the epithelium), than the posterior side (in the mid-stroma) during healing. The flap interface was difficult to locate in the OCT images at 6 months.
Conclusion: All the CRTTM lenses used in this project produced more corneal swelling than that seen normally overnight without lens wear. In order for these lenses to be worn safely for long periods of time without affecting the health of the cornea, they need to be manufactured from the highest oxygen transmissible material available. The long-term effect of thinning on the epithelium's barrier properties needs to be monitored closely.
Global topographical thickness of the cornea and epithelium was measured using OCT in normal, RGP lens wearing and keratoconic eyes. Corneal and epithelial thickness was not symmetrical across meridians. The epithelium of RGP lens wearers was slightly thinner than normal, but not as thin as in keratoconics, suggesting that the epithelial change seen in keratoconus is mainly due to the condition.
Post-LASIK corneal and epithelial thickness profiles were not the same for myopic and hyperopic subjects, since the ablation patterns vary. Epithelial thickening in the mid-periphery had not recovered by six months in myopes or hyperopes, possibly indicating epithelial hyperplasia. Light backscatter profiles were used to monitor the recovery of the LASIK flap interface, showing the band of light backscatter around the flap interface to decrease as the cornea healed.
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Sauvageot, Beneria Paola. "Efecto de la cirugía refractiva corneal sobre la osmolaridad lagrimal y otros parámetros del flujo lagrimal." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/322816.
Full textAbstract:
OBJETIVO: Comparar el efecto de la fotoqueratomileusis in situ asistida con láser de femtosegundos (LASIK) y la queratectomía fororrefractiva (PRK) sobre la osmolaridad y otros parámetros de ojo seco.
MÉTODOS: Estudio prospectivo comparativo que incluye 56 ojos de 56 pacientes intervenidos de LASIK o PRK. Para cada paciente de cada grupo ( LASIK o PRK) se valoró el cuestionario OSDI (Ocular Surface Disease Index), el tiempo de rotura lagrimal (BUT), la tinción corneal, el test de Schirmer con y sin anestesia, la estesiometría corneal y la osmolaridad antes de la cirugía y a los 3, 6 y 12 meses de la intervención.
RESULTADOS: No se observaron diferencias en los parámetros de ojo seco entre los 2 grupos excepto para la estesiometría corneal que presentó una disminución significativa a los 3 meses de la intervención en el grupo LASIK comparado con el grupo PRK (U=270; P=0,043). La sensibilidad corneal presentó una disminución significativa a los 3 meses en ambos grupos comparado con los valores preoperatorios pero volvió a sus valores preoperatorios a los 6 meses de la cirugía en el grupo PRK y a los 12 meses en el grupo LASIK. La osmolaridad lagrimal no presentó cambios significativos a los 3 meses de la intervención comparado con los valores preoperatorios pero se observó un incremento significativo de sus valores a los 6 meses (LASIK group, P=0,04; PRK group, P=0,006) y a los 12 meses tras la intervención (LASIK group, P=0,005; PRK group, P=0,004).
CONCLUSIONES: A los 12 meses de la intervención, todas las variables vuelven a sus valores basales preoperatorios excepto la osmolaridad lagrimal. En ambos grupos, la osmolaridad lagrimal presenta alteraciones de inicio tardío y permanece significativamente aumentada un año después de la cirugía. Un mayor seguimiento será necesario para completar el estudio del efecto de la cirugía refractiva corneal sobre la osmolaridad lagrimal.PURPOSE: To compare the impact of laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) on tear osmolarity and other dry eye tests. METHODS: A prospective and comparative study was done where 56 eyes of 56 myopic patients who underwent LASIK or PRK surgery and fulfilled the inclusion criteria were included in 2 matched groups. Dry eye tests were evaluated before the surgery and at 3, 6, and 12 months postoperatively, and included tear osmolarity, ocular surface disease index (OSDI) questionnaire, Schirmer I test with and without anesthesia, corneal esthesiometry, tear break up time (TBUT) and corneal staining. RESULTS: No significant difference in dry eye tests between the 2 groups was observed at any point. Only corneal sensibility was significantly decreased in LASIK group compared to PRK group after 3 months (U=270; P=0,043). Corneal sensibility was significantly reduced after 3 months compared to preoperative values in both groups but recovered to statistically similar to preoperative values after 6 (PRK group) and 12 months (LASIK group). Tear osmolarity values were comparable to preoperative values after 3 months but significantly increased in both groups after 6 (LASIK group, P=0,04; PRK group, P=0,006) and 12 months (LASIK group, P=0,005; PRK group, P=0,004). CONCLUSIONS: There was no significant difference in tear osmolarity and other dry eye tests between LASIK and PRK at any point of the follow-up except for corneal sensitivity which was significantly lower in the LASIK group than in the PRK group at 3 months postoperatively. Tear osmolarity significantly increased in both groups at 6 months after surgery compared to preoperative values, and remained statistically higher one year postoperatively. A longer follow-up will be necessary to assess whether tear osmolarity recovers its preoperative values after corneal refractive surgery.
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林穎華 and Wing-wah Phoebe Lam. "A systematic review of postoperative treatments for laser eye surgery." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31970643.
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Canheto, Mónica Alexandra Robalo. "Miopia e seus tratamentos." Master's thesis, Universidade da Beira Interior, 2012. http://hdl.handle.net/10400.6/1142.
Full textAbstract:
A elaboração deste relatório, afigura-se como o culminar do período de estágio que foi desenvolvido entre o mês de Novembro de 2011 e o mês de Maio de 2012 na Clínica Oftalmológica Professor Doutor Manuel Monteiro Pereira, no Porto.
O estágio consistiu no acompanhamento de consultas, cirurgias, realização e análise de exames complementares de diagnóstico, com o intuito de consolidar conhecimentos de correção e tratamento das diversas ametropias, com principal destaque para a miopia. Promovendo assim, uma maior sensibilização para este tema, uma vez que se trata da ametropia com maior grau de prevalência a nível mundial.In this report, appears as the culmination of the probationary period that was developed between November 2011 and May of 2012 at the Clínica Oftalmológica Professor Doutor Manuel Monteiro Pereira, Oporto. The stage consisted of follow-up consultations, surgeries, conduct and analysis of diagnostic exams, in order to consolidate knowledge of correction and treatment of various refractive errors, with main focus on Myopia. Thus promoting a greater awareness of this issue, since it comes with a higher degree of ametropia prevalence worldwide.
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Ralla, Bernhard [Verfasser], and Gerd [Akademischer Betreuer] Geerling. "Über den Einfluss der Kollagenquervernetzung der Cornea auf die Laser-in-situ-Keratomileusis (LASIK) / Bernhard Ralla. Betreuer: Gerd Geerling." Würzburg : Universitätsbibliothek der Universität Würzburg, 2012. http://d-nb.info/1022790935/34.
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Klamann, André Philipp [Verfasser], and Achim [Akademischer Betreuer] Langenbucher. "Entwicklung und Rehabilitation der Sehfunktion nach Wellenfrontanalyse geführter Laser-in-situ-Keratomileusis (LASIK) / André Philipp Klamann. Betreuer: Achim Langenbucher." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2016. http://d-nb.info/1099952123/34.
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Velarde, Rodríguez José Ignacio. "Sobre el encurvamiento periférico en la topografía corneal tras cirugía refractiva (LASIK) para corrección de miopía y la relación con parámetros oculares biomecánicos y quirúrgicos. Steepening in peripheral corneal topography after LASIK surgery in myopic patients and its relation with biomechanical and surgical parameters." Doctoral thesis, Universidad de Cantabria, 2014. http://hdl.handle.net/10803/247506.
Full textAbstract:
La cirugía refractiva corneal corrige los errores refractivos modificando la curvatura de la córnea. Después de la cirugía de la miopía con técnica LASIK, se ha observado un aplanamiento central inesperado de origen biomecánico y un encurvamiento periférico. El objetivo de este trabajo fue estudiar la relación entre ambos fenómenos y otros parámetros oculares. Se realizó un estudio retrospectivo de una serie quirúrgica, utilizando las topografías tangenciales diferenciales. El encurvamiento se caracterizó mediante tres parámetros: incremento de potencia, diámetro de la zona de mayor valor (anillo) y ángulo del gradiente periférico. Un estudio prospectivo analizó su presencia post-ablación en cuatro tipos de modelos esféricos experimentales sin respuesta biomecánica. El encurvamiento periférico se situó entre la zona óptica y la zona de transición, con un ligero desplazamiento lateral debido al ángulo kappa. No se halló correlación con el aplanamiento central inesperado. Tiene una correlación positiva y significativa con el gradiente teórico y con la edad. En los modelos experimentales, se presentó un anillo de encurvamiento periféricoCorneal refractive surgery corrects refractive errors by modifying the corneal curvature. After myopia surgery with LASIK, a central unexpected flattening of biomechanical origin and a peripheral steepening have been observed. The aim of this work was to study the relation between both facts and other ocular parameters. A retrospective study of a surgical series was done using the tangential differential topography. Steepening was characterized by three parameters: increase of power, diameter of the zone of major value (ring) and the angle of the peripheral gradient. A prospective study analyzed post-ablation peripheral steepening in four types of spherical experimental models without biomechanical response. The peripheral steepening was placed between the optical zone and the transition zone, with a light lateral displacement due to angle kappa values. No correlation with the central unexpected flattening was found, whereas it has a positive and significant correlation with the theoretical gradient and with the age. In the experimental models, a ring of peripheral steepening was present.
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Mccafferty, Sean Joseph. "Analysis and Application of Opto-Mechanics to the Etiology of Sub-Optimal Outcomes in Laser Corrective Eye Surgery and Design Methodology of Deformable Surface Accommodating Intraocular Lenses." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/556806.
Full textAbstract:
Overview: Optical concepts as they relate to the ophthalmologic correction of vision in corneal laser vision correction and intraocular lens design was examined. Purpose: The interaction between the excimer laser and residual corneal tissue in laser vision correction produces unwanted side effects. Understanding the origin of these artifacts can lead to better procedures. Furthermore, accommodating intraocular lenses offer a potential for eliminating presbyopia. Understanding the properties of a new accommodating intraocular lens incorporating a deformable interface may lead to advances in cataract surgery. Introduction: Corneal surface irregularities following laser refractive procedures are commonly seen. They regularly result in a patient’s decreased best corrected visual acuity and decreased contrast sensitivity. These changes are only seen in biologic tissue and the etiology has been elusive. A thermal response has been theorized and was investigated in this research. In addition, intraocular lenses using a mechanically deforming interface to change their power in order to duplicate natural accommodation have been developed. The deforming interface(s) induce optical aberrations due to irregular deformations. Design efforts have centered on minimizing these deformations. Both of the ophthalmic applications have been analyzed using finite element analysis (FEA) to understand their inherent optical properties. Methods: FEA modeling of thermal theory has been applied to verify that excimer laser induced collagen contraction creates corneal surface irregularities and central islands. A mathematical model which indicates the viability of the theory was developed. The modeling results were compared to post ablation changes in eyes utilizing an excimer (ArF 193 nm), as well as non-ablative thermal heating in eyes with a CO₂ laser. Addition modeling was performed on an Intraocular lens prototype measuring of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio. Prototype verified mathematical models were utilized to optimize optical and mechanical design parameters to maximize the image quality and minimize the required force. Results: The predictive model shows significant irregular central buckling formation and irregular folding. The amount of collagen contraction necessary to cause significant surface changes is very small (0.3%). Uniform scanning excimer laser ablation to corneal stroma produces a significant central steepening and peripheral flattening in the central 3mm diameter. Isolated thermal load from uniform CO₂ laser irradiation without ablation also produces central corneal steepening and paracentral flattening in the central 3mm diameter. The iterative mathematical modeling based upon the intraocular lens prototype yielded maximized optical and mechanical performance through varied input mechanical and optical parameters to produce a maximized visual Strehl ratio and a minimized force requirement. Conclusions: The thermal load created by laser irradiation creates a characteristic spectrum of morphologic changes on the porcine corneal stromal surface which correlates to the temperature rise and is not seen inorganic, isotropic material. The highly similar surface changes seen with both lasers are likely indicative of temperature induced transverse collagen fibril contraction and stress re-distribution. Refractive procedures which produce significant thermal load should be cognizant of these morphological changes. The optimized intraocular lens operates within the physiologic constraints of the human eye including the force available for full accommodative amplitude using the eye’s natural focusing feedback, while maintaining image quality in the space available. Optimized optical and mechanical performance parameters were delineated as those which minimize both asphericity and actuation pressure. The methodology combines a multidisciplinary basic science approach from biomechanics, optical science, and ophthalmology to optimize an intraocular lens design suitable for preliminary trials.
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Setareh, Sanj Maryam [Verfasser], and Toam [Akademischer Betreuer] Katz. "Effektivitäts- und Zufriedenheitsanalyse nach LASIK bei präpresbyopen und presbyopen Patienten nach Implantation einer bifokalen Intraokularlinse (MIOL) / Maryam Setareh Sanj ; Betreuer: Toam Katz." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/1203301596/34.
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Setareh, Sanj Maryam Verfasser], and Toam [Akademischer Betreuer] [Katz. "Effektivitäts- und Zufriedenheitsanalyse nach LASIK bei präpresbyopen und presbyopen Patienten nach Implantation einer bifokalen Intraokularlinse (MIOL) / Maryam Setareh Sanj ; Betreuer: Toam Katz." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/1203301596/34.
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Garrett, Kenneth. "Risk factors for retreatment and a comparative analysis of wavefront-guided versus conventional treatment for residual myopic and hyperopic correction in LASIK." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12108.
Full textAbstract:
Thesis (M.A.)--Boston UniversityA retrospective chart review performed from December 2007 to September 2012 identified 3,223 patients that underwent LASIK treatment with the STAR S4 IRTM Excimer Laser. In this group, 109 patients (3.4%) required a retreatment. All charts were reviewed for pre-operative age, gender, initial manifest refraction spherical equivalent (MRSE), total astigmatism, and method of primary LASIK treatment (conventional versus wavefront-guided) to identify risk factors that may lead to retreatment. A second chart review from December 2007 to January 2013 identified 120 patients who had a retreatment. A comparative analysis on the final post-operative visual acuity and MRSE was performed on this group to evaluate the efficacy of conventional versus wavefront-guided retreatment. Increased incidence rates of retreatment post- LASIK were associated with pre-operative age greater than 40 years (p < 0.001), initial MRSE greater than -5.0 diopters (D) (p < 0.004), hyperopia (p <0.031), and astigmatism greater than -1 D (p < 0.001). There was a 12.3% incidence rate of epithelial ingrowth post-retreatment, and a 1.7% development of clinically significant epithelial ingrowth, which necessitated flap lift and scrapping. There was no statistically significant difference in visual acuity and MRSE post- retreatment with either conventional or wavefront-guided retreatment for residual hyperopic or myopic refractions. All secondary retreatments were in the wavefront-guided retreatment groups (myopic p = 0.16 and hyperopic p = 0.01). Ablation depth was significantly different between myopic conventional and wavefront-guided (p = 0.01) and hyperopic conventional and wavefront-guided (p = 0.04). While no statistically significant difference was found between final outcome vision between conventional and wavefront-guided treatments, conventional treatment ablating less corneal stroma and resulting in fewer complications and additional retreatments provides a strong argument for retreatment with conventional over wavefront-guided.
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Bauer, Eva Lucia [Verfasser], and Ralf-Christian [Akademischer Betreuer] Lerche. "Korneale Biomechanik nach Laser-in-situ-Keratomileusis(LASIK) : Retrospektive Analyse der Corneal VisualisationScheimpflug Technology (CORVIS® ST) Parameter / Eva Lucia Bauer ; Betreuer: Ralf-Christian Lerche." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1156462193/34.
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Tang, Maolong. "Corneal mean curvature mapping application in laser refractive surgery /." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1094593446.
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Helal, Shirin Nadia [Verfasser], and Gisbert [Akademischer Betreuer] Richard. "Einfluss der Wahl der Zentrierungsachse bei LASIK auf den Winkel Kappa prä- und intraoperativ bei Hyperopie, Myopie und gemischtem Astigmatismus / Shirin Nadia Helal. Betreuer: Gisbert Richard." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://d-nb.info/1070188379/34.
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Li, Yan. "Image Processing and Clinical Applications of Anterior Segment Optical Coherence Tomography." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1212436115.
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Pesochinsky, Nina. "Effect of refractive vision correction of myopia and hyperopia through laser surgery (LASIK & PRK) on symptoms of depression, stress perception and self-esteem in adults (22-55)." Thesis, Capella University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10288076.
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The purpose of this study was to assess the effects of refractive vision correction through laser surgery (LASIK & PRK) of adults of working age (22-55). This study examined and compared the symptoms of depression, stress perception, and self-esteem prior to surgery and one month after surgery, when sufficient healing has occurred. Research has shown that vision impairment has been reported to be one of the 10 most significant causes of disability in the United States, and, even though clinicians are encouraged to assess emotional response to vision loss, the psychological factors that that play a role in adjustment to vision loss have not been sufficiently studied.
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Міщенко, Т. А. "Лазерна корекція зору." Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/66872.
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Сучасний світ – це світ інформації та ІТ-технологій. Людина багато
читає, працює з монітором комп’ютера і на очі людини лягає основне
навантаження. І, якщо в молодому віці дефекти зору можуть
виправлятися самим оком, то з віком стан очей погіршується і
потрібно проводити корекцію зору.
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López, Fortuny Marta. "Estudio comparativo de calidad de vida entre pacientes operados mediante lente implantable intraocular fáquica (ICL) y queratomiulesis por láser (LASIK), utilizando un cuestionario validado específico (QIRC) para miopía entre 5 y 10 dioptrías." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670618.
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INTRODUCCIÓ
Els qüestionaris de qualitat de vida relacionats amb la visió són eines addicionals per aconseguir l’avaluació integral del aresultat obtingut després d’una cirurgia refractiva, ja que inclouen tant la perspectiva de l’pacient pel que fa al seu estat funcional com la satisfacció relacionada amb la seva visió després de l’tractament quirúrgic.
OBJECTIU
Comparar la qualitat de vida entre pacients operats de lent intraocular respectant el cristal·lí natural o fàquica (ICL) i cirurgia refractiva amb làser (LASIK) en miops d’entre 5 a 10 diòptries per valorar la utilitat en la decisió d’utilitzar una tècnica quirúrgica o una altra .
Material i mètodes
Estudi retrospectiu realitzat en 120 ulls de 60 pacients que es van sotmetre a cirurgia amb implant de LASIK i ICL. Els pacients eren avaluats abans de la cirurgia i després de la cirurgia a l’endemà, als dos mesos i a l’any. El qüestionari QIRC es va realitzar amb un mínim de 24 mesos i altres variables avaluades van ser l’agudesa visual, els defectes refractius, sensibilitat a l’contrast, pupil·la, test de Schirmer, Estesiometría i índexs de la cirurgia.
RESULTATS
En el nostre estudi vam obtenir que la puntuació de l’qüestionari de la qualitat de vida relacionada amb la correcció refractiva (QIRC) va ser més gran per als pacients operats de lent implantable fàquica (ICL) que per als de queratomiulesis in situ assistida per làser (LASIK), tot i que no es va aconseguir significació estadística.
CONCLUSIONS
Les dues tècniques refractives (ICL i LASIK) poden ser una bona opció per a la correcció de pacients miops de 5 a 10 diòptries.INTRODUCCIÓN Los cuestionarios de calidad de vida relacionados con la visión son herramientas adicionales para lograr la evaluación integral del resultado obtenido tras una cirugía refractiva, ya que incluyen tanto la perspectiva del paciente con respecto a su estado funcional como la satisfacción relacionada con su visión después del tratamiento quirúrgico. OBJETIVO Comparar la calidad de vida entre pacientes operados de lente intraocular respetando el cristalino natural o fáquica (ICL) y cirugía refractiva con láser (LASIK) en miopes de entre 5 a 10 dioptrías para valorar la utilidad en la decisión de utilizar una técnica quirúrgica u otra. MATERIAL Y MÉTODOS Estudio retrospectivo realizado en 120 ojos de 60 pacientes que se sometieron a cirugía con implante de LASIK e ICL. Los pacientes eran evaluados antes de la cirugía y después de la cirugía al día siguiente, a los dos meses y al año. El cuestionario QIRC se realizó con un mínimo de 24 meses y otras variables evaluadas fueron la agudeza visual, los defectos refractivos, sensibilidad al contraste, pupila, test de Schirmer, Estesiometría e índices de la cirugía. RESULTADOS En nuestro estudio obtuvimos que la puntuación del cuestionario de la calidad de vida relacionada con la corrección refractiva (QIRC) fue mayor para los pacientes operados de lente implantable fáquica (ICL) que para los de queratomiulesis in situ asistida por láser (LASIK), aunque no se alcanzó significación estadística. CONCLUSIONES Ambas técnicas refractivas (ICL y LASIK) pueden ser una buena opción para la corrección de pacientes miopes de 5 a 10 dioptrías.
INTRODUCTION Vision-related quality of life questionnaires are additional tools to achieve the comprehensive evaluation of the result obtained after refractive surgery, since they include both the patient’s perspective regarding their functional status and satisfaction related to their vision after treatment. surgical. OBJECTIVE To compare the quality of life between patients operated on by intraocular lens respecting the natural or phakic lens (ICL) and refractive laser surgery (LASIK) in myopia with 5 to 10 diopters to assess the utility in the decision to use one surgical technique or another. . MATERIAL AND METHODS Retrospective study performed on 120 eyes of 60 patients who underwent surgery with LASIK and ICL implantation. Patients were evaluated before surgery and after surgery the following day, two months and one year. The QIRC questionnaire was performed with a minimum of 24 months and other variables evaluated were visual acuity, refractive defects, contrast sensitivity, pupil, Schirmer test, Esthesiometry and surgery indices. RESULTS In our study, we obtained that the score of the refractive correction-related quality of life questionnaire (QIRC) was higher for patients operated on phakic implantable lens (ICL) than for laser-assisted in situ keratomyelulesis (LASIK), although statistical significance was not reached. CONCLUSIONS Both refractive techniques (ICL and LASIK) can be a good option for the correction of myopic patients with 5 to 10 diopters.
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Wanner, Emanuel [Verfasser], and Wolfgang [Akademischer Betreuer] Mayer. "Corneale densitometrische Untersuchung und funktionelle Ergebnisse nach Femtosekundenlaser-geführter Laser-assistierter in situ Keratomileusis (Femto-LASIK) und Small Incision Lenticule Extraction (SMILE) zur Korrektur von Myopie und Astigmatismus / Emanuel Wanner ; Betreuer: Wolfgang Mayer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1206877847/34.
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Júnior, Jackson Barreto. "Estudo comparativo entre a ceratectomia fotorrefrativa e a ceratomileusis in situ a laser guiadas pela análise de frente de onda." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-31082010-174113/.
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OBJETIVO: Comparar os resultados de duas técnicas cirúrgicas guiadas pela análise de frente de onda, a ceratectomia fotorrefrativa (PRK) e a ceratomileusis in situ a laser (LASIK), para correção da miopia baixa a moderada, associada ou não ao astigmatismo. LOCAL: Setor de Cirurgia Refrativa da Clínica Oftalmológica do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brasil. MÉTODOS: Estudo prospectivo randomizado envolvendo 70 olhos (35 pacientes) submetidos ao LASIK personalizado em um olho e PRK personalizado no olho contralateral para correção de miopia até 5 dioptrias (D) e astigmatismo até 1,5D. Avaliou-se acuidade visual não-corrigida (AVNC), melhor acuidade visual corrigida (MAVC), resultados refratométricos, aberrometria, sensibilidade ao contraste fotópico e mesópico, acuidade visual de baixo contraste (AVBC), qualidade da imagem retiniana (Função de Transferência Modular e Strehl ratio) e espalhamento intraocular de luz (EIL) no período pré-operatório e no 1o, 3o, 6o e 12o mês pós-operatório. RESULTADOS: O equivalente esférico (EE) médio pré-operatório foi -2,57 ± 0,95D no grupo LASIK e, no grupo PRK, -2,52 ± 0,90D (p = 0,722). No 12o mês pósoperatório (PO), EE foi -0,06 ± 0,33D e -0,12 ± 0,41D, respectivamente (p = 0,438). No grupo LASIK, 60,0% dos olhos apresentaram AVNC 20/16 e 96,7% 20/20, e no grupo PRK, 66,6% e 96,7%, respectivamente (p = 0,667). No período pré-operatório, o total das aberrações de alta ordem (HOAs) foi 0,37 ± 0,09 m no grupo LASIK e 0,36 ± 0,11m no grupo PRK (p = 0,752). No 12o mês PO, o total das HOAs foi 0,46 ± 0,21m no grupo LASIK e 0,42 ± 0,14m no grupo PRK (p = 0,438). Tanto o teste de sensibilidade ao contraste fotópico como o mesópico apresentaram resultados semelhantes entre as técnicas, exceto pela freqüência 1,5 ciclos por grau (cpg) do teste mesópico no 12o mês PO, a favor do grupo PRK. Os índices de qualidade da imagem retiniana mostraram comportamento similar entre as técnicas ao longo do seguimento. Não houve aumento significativo do espalhamento intraocular da luz em ambos os grupos, quatro olhos cursaram com aumento transitório. CONCLUSÃO: Dentro das condições deste estudo, ambas as técnicas apresentaram excelentes resultados refratométricos e função visual semelhante. Apesar do tratamento personalizado guiado pela análise de frentes de onda, houve indução das HOAs, de forma similar, tanto no LASIK como no PRK.PURPOSE: To compare clinical results of two wavefront-guided treatments, photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), for low to moderate myopia correction, with or without astigmatism. SETTING: Refractive Surgery Service, General Hospital, University Of São Paulo, São Paulo, Brazil. METHODS: Prospective randomized study of 70 eyes (35 patients) submitted to custom LASIK and custom PRK (contralateral eye) for myopia up to 5D and astigmatism up to 1,5D. Uncorrected visual acuity (AVNC), best-corrected visual acuity (MAVC), refractive results, wavefront analysis, photopic and mesopic contrast sensitivity, low contrast visual acuity (AVBC), retinal image quality (Modulation Transfer Function and Strehl ratio) and intraocular straylight (EIL) were performed preoperatively and at one, three, six and twelve months postoperatively. RESULTS: The mean preoperative spherical equivalent (EE) was -2,57 ± 0,95D in the LASIK group and -2,52 ± 0,90D in the PRK group (p = 0,722). At twelve months postoperatively (PO), the mean EE was -0,06 ± 0,33D and -0,12 ± 0,41D, respectively (p = 0,438). In the LASIK group, 60,0% had AVNC 20/16 and 96,7% 20/20, and in the PRK group, 66,6% e 96,7%, respectively (p = 0,667). The mean pre-treatment total high-order aberrations (HOAs) was 0,37 ± 0,09 m in the LASIK group and 0,36 ± 0,11m in the PRK group (p = 0,752). At twelve months PO, the mean total HOAs was 0,46 ± 0,21m in the LASIK group and 0,42 ± 0,14 m in the PRK group (p = 0,438). No significant difference in photopic and mesopic contrast sensitivity between groups was noted, apart from the 1,5 cpg frequency of the mesopic test, favoring PRK, at the 12th month PO. Similar results were found for retinal image quality metrics during the follow-up. No significant increase of the intraocular straylight was found for both techniques, four eyes presented transitory elevations. CONCLUSION: In the conditions of this study, both techniques had excellent refractive results and similar visual function. In spite of the wavefront-guided treatments, HOAs were induced similarly after LASIK and PRK