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Journal articles on the topic 'Cornea Keratoconus. LASIK (Eye surgery)'
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Abdolahian, Milad, Mohammad Ali Moalem, Mohammadreza Jahady Hoseiny, Farsad Noorizadeh, and Athar Zareei. "Keratorefractive Surgery Outcomes in Keratoconus Suspect Patients." Journal of Ophthalmology 2020 (December 2, 2020): 1–11. http://dx.doi.org/10.1155/2020/8823744.
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Purpose. To examine the outcomes of keratorefractive surgeries in keratoconus suspect patients. Methods. This study included 192 keratoconus suspects (351 eyes), treated with photorefractive keratectomy (PRK) (211 eyes), Lasik (96 eyes), and Femto-Lasik (44 eyes) surgeries in an eye clinic. The best spectacle-corrected visual acuity (BSCVA) and subjective refraction were evaluated preoperatively and postoperatively (three months and five years after the procedure). The Orbscan II topography system was also used preoperatively and five years after the procedure. Results. The patients’ mean age was 31.6 ± 5.49 years (range: 21–47 years) in the last follow-up. There was no significant difference between the preoperative and postoperative mean values of BSCVA in any of the surgical methods ( P = 0.49). The mean spherical equivalent, cylindrical power, corneal curvature, the thinnest corneal thickness, and the central corneal thickness decreased significantly in the last follow-up ( P < 0.001). Four patients (3.50%) in the PRK group and one patient (1.85%) in the Lasik group needed glasses in the last follow-up. Eleven cases of corneal ectasia were detected in the last follow-up (six eyes of four patients [2.84%] and five eyes of four patients [5.20%] in the PRK and Lasik groups, respectively). Conclusion. In the present study, the high risk of postoperative ectasia was detected in keratoconus suspects following PRK and Lasik surgeries. According to the results, it can be concluded that Femto-Lasik surgery provides better outcomes than Lasik and PRK. Overall, the surgical criteria are suggested to be evaluated case by case, and the patients must be followed up over time to assess the corneal topography and refraction stability.
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Tatar, Mehmet Gurkan, Feride Aylin Kantarci, Aydin Yildirim, Haşim Uslu, Hatice Nur Colak, Hasan Goker, and Bulent Gurler. "Risk Factors in Post-LASIK Corneal Ectasia." Journal of Ophthalmology 2014 (2014): 1–4. http://dx.doi.org/10.1155/2014/204191.
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Purpose. To evaluate the risk factors for post-laser in situ keratomileusis (LASIK) ectasia.Materials and Methods. Medical records of 42 eyes of 28 (10 women, 18 men) patients who developed corneal ectasia after LASIK were retrospectively reviewed. Topographical features and surgical parameters of those patients were evaluated.Results. The mean age of patients was34.73±6.50(23–48) years and the mean interval from LASIK to the diagnosis of post-LASIK ectasia was36.0±16.92(12–60) months. The following factors were determined as a risk factors: deep ablation (>75 μm) in 10 eyes, FFK (forme fruste keratoconus) in 6 eyes, steep cornea (>47 D) in 3 eyes, pellucid marginal degeneration (PMD) in 2 eyes, thin cornea (<500 μm) in 2 eyes, thin and steep cornea in 2 eyes, thin cornea and deep ablation in 5 eyes, FFK and steep cornea in 2 eyes, and FFK, steep cornea, and deep ablation in 1 eye. However no risk factor has been determined in 9 eyes (21.4%).Conclusion. The findings of our study showed that most of the patients who developed post-LASIK ectasia have a risk factor for post-LASIK ectasia. However, the most common risk factor was deep ablation.
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Valbon, Bruno Freitas, Juliana Glicéria, Rodrigo Santos, and Milton Ruiz Alves. "Unilateral Corneal Ectasia after Bilateral LASIK: The Thick Flap Counts." International Journal of Keratoconus and Ectatic Corneal Diseases 2, no. 2 (2013): 79–83. http://dx.doi.org/10.5005/jp-journals-10025-1056.
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ABSTRACT Purpose To report a case of post-LASIK corneal ectasia due to a thick flap, while the contralateral eye did not develop ectasia after an incomplete deep flap cut, followed by a thinner flap LASIK procedure. Methods Case report Results This 45 years old female patient had bilateral myopic LASIK in 1999. Preoperative anterior curvature map was regular with no signs of keratoconus. Central keratometry was 42.88 × 44.70 @ 163 in OD and 43.43 × 45.24 @ 175 in OS. Ultrasound central corneal thickness was 586 μm and 619 μm in the right eye and left eye, respectively. Corneal OCT identified a deep meniscus-shaped LASIK flap, with a central thickness of a 392 μm in the right eye, and an incomplete deep peripheral cut in the left eye with a thinner meniscus-shaped LASIK flap. Conclusion Unilateral ectasia after LASIK may occur due to a thick flap which leads to biomechanical failure of the cornea. How to cite this article Valbon BF, Ambrosio R Jr, Glicéria J, Santos R, Luz A, Alves MR. Unilateral Corneal Ectasia after Bilateral LASIK: The Thick Flap Counts. Int J Kerat Ect Cor Dis 2013;2(2):79-83.
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Surkova, V. K., A. R. Khalimov, and G. M. Kazakbaeva. "Keratectasias and modern methods of their treatment." POINT OF VIEW. EAST – WEST, no. 2 (May 31, 2021): 84–88. http://dx.doi.org/10.25276/2410-1257-2021-2-84-88.
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The review article provides non-surgical (spectacle and contact correction, ultraviolet corneal crosslinking) and surgical methods (corneal transplantation, intrastromal implantation of segments and rings) for the treatment of keratoectasias and, in particular, keratoconus. The authors present their own original developments of scientists from the Ufa Research Institute of Eye Diseases in the field of cross-linking and various types of keratoplasty, as well as promising areas of clinical research on the combined treatment of keratectasias: cross-linking in combination with LASIK, intrastromal introduction of segments and rings. Key words: cornea, keratectasias, keratoconus, non-surgical and surgical methods of treatment.
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Hayes, Sally, Siân R. Morgan, and Keith M. Meek. "Keratoconus: cross-linking the window of the eye." Therapeutic Advances in Rare Disease 2 (January 2021): 263300402110035. http://dx.doi.org/10.1177/26330040211003573.
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Keratoconus is a condition in which the cornea progressively thins and weakens, leading to severe, irregular astigmatism and a significant reduction in quality of life. Although the precise cause of keratoconus is still not known, biochemical and structural studies indicate that overactive enzymes within the cornea break down the constituent proteins (collagen and proteoglycans) and cause the tissue to weaken. As the disease develops, collagen fibres slip past each other and are redistributed across the cornea, causing it to change shape. In recent years, it was discovered that the photochemical induction of cross-links within the corneal extracellular matrix, through the use of riboflavin and ultraviolet (UVA) light, could increase the strength and enzymatic resistance of the tissue and thereby halt keratoconus progression. Worldwide acceptance and use of riboflavin/UVA corneal cross-linking therapy for halting keratoconus progression has increased rapidly, in accordance with the growing body of evidence supporting its long-term effectiveness. This review focusses on the inception of riboflavin/UVA corneal cross-linking therapy for keratoconus, its clinical effectiveness and the latest scientific advances aimed at reducing patient treatment time, improving patient comfort and increasing patient eligibility for treatment. Plain language summary Review of current treatments using cross-linking to halt the progress of keratoconus Keratoconus is a disease in which the curved cornea, the transparent window at the front of the eye, weakens, bulges forward into a cone-shape and becomes thinner. This change of curvature means that light is not focussed onto the retina correctly and vision is progressively impaired. Traditionally, the effects of early keratoconus were alleviated by using glasses, specialist contact lenses, rings inserted into the cornea and in severe cases, by performing a corneal transplant. However, it was discovered that by inducing chemical bonds called cross-links within the cornea, the tissue could be strengthened and further thinning and shape changes prevented. The standard cross-linking procedure takes over an hour to perform and involves the removal of the cells at the front of the cornea, followed by the application of Vitamin B2 eye drops and low energy ultraviolet light (UVA) to create new cross-links within the tissue. Clinical trials have shown this standard procedure to be safe and effective at halting keratoconus progression. However, there are many treatment modifications currently under investigation that aim to reduce patient treatment time and increase comfort, such as accelerated cross-linking procedures and protocols that do not require removal of the surface cells. This review describes the different techniques being developed to carry out corneal cross-linking efficiently and painlessly, to halt keratoconus progression and avoid the need for expensive surgery.
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Song, Yinyu, Lihua Fang, Ruirui Du, Luchao Lin, and Xingming Tao. "The corneal biomechanical changes after SMILE and LASIK refractive surgery were compared based on finite element analysis." E3S Web of Conferences 271 (2021): 03045. http://dx.doi.org/10.1051/e3sconf/202127103045.
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The three-dimensional (3D) finite element model of human eye was established, and the intraocular pressure (IOP) was loaded to simulate refractive surgery. The biomechanical properties of human cornea after SMILE and LASIK surgery were studied from the stress, strain and induced wavefront aberration. Our results showed that SMILE had less impact on the biomechanics, having less stress and strain changes than LASIK. However, the stress and strain of the cornea increased with the increase of the diopter and were concentrated in the central region. We also investigated the changes in wavefront aberrations of the cornea after surgery, and the results indicated that the defocus and vertical commotion were significantly affected by SMILE and LASIK surgery, while the remaining aberrations were approximately unchanged. In conclusion, both SMILE and LASIK sergury procedures changed the postoperative corneal biomechanics, but SMILE had less impact on the biomechanics of corneal.
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Hefner-Shahar, Hagar, and Nir Erdinest. "High-order Aberrations in Keratoconus." International Journal of Keratoconus and Ectatic Corneal Diseases 5, no. 3 (2016): 128–31. http://dx.doi.org/10.5005/jp-journals-10025-1133.
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ABSTRACT With all the technological advances today and the increasing number of people undergoing refractive surgery, the importance of detecting keratoconus (KC) prior to surgery has become evident. Although by using a topographer we can detect early stage KC, however, by using wavefront analysis technology, we are able to detect KC at an even earlier stage. Every eye possesses a number of aberrations. However, in a KC patient's eye, there are approximately five to six times the numbers of high-order aberrations (HOAs) than in a healthy eye. Using this technology to detect and assess the HOAs, it was found that in a KC cornea, it is possible to detect at a very early stage a much higher value of vertical coma aberrations compared with a normal eye. By using this technology, it is possible to study and understand the characteristics of the quality of the image on the retina, thereby understanding its impact on the patient's visual quality. How to cite this article Hefner-Shahar H, Erdinest N. Highorder Aberrations in Keratoconus. Int J Kerat Ect Cor Dis 2016;5(3):128-131.
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Shilova, T. Yu. "ReLEx® SMILE® – the third generation of laser eye surgery." EYE GLAZ 22, no. 4(132) (December 16, 2020): 52–58. http://dx.doi.org/10.33791/2222-4408-2020-4-52-58.
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ReLEx® (Refractive lenticule extraction) SMILE® (SMall Incision Lenticula Extraction) is the third generation of laser eye surgery, which is a follow-on to PRK (the first generation) and LASIK (the second generation). This technology has expanded the possibilities for the comfort and safety of the procedure, reduced the requirements for the thickness of the cornea, and made it extremely comfortable for the patient. SMILE® method helps improve vision in case of myopia, myopic and mixed astigmatism. The article analyzes the advantages and disadvantages of this technology, its possible risks and side effects. The data represented in this article was obtained by analyzing scientific publications and practical expertise.
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Panova, I. E., A. V. Titov, and D. R. Mirsaitova. "Tear Replacement Therapy in Medical Support of Patients after Femto-LASIK Keratorefractive Surgery." Ophthalmology in Russia 17, no. 2 (June 23, 2020): 274–80. http://dx.doi.org/10.18008/1816-5095-2020-2-274-280.
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Purpose — to analyze the effectiveness of artificial tear drops HYLOPARIN-COMOD® in the complex medical support of the FemtoLASIK operation based on monitoring of clinical, functional and morphometric indicators of the eye surface’s condition. Patients and methods. The study included 25 patients (50 eyes) who underwent a keratorefractive surgery (Femto-LASIK) and were prescribed instillations of artificial tear drops HILOPARIN-COMOD®. To analyze the effectiveness of artificial tear drops HYLOPARIN-COMOD® in the complex medical support of the Femto-LASIK operation based on monitoring of clinical, functional and morphometric indicators of the eye surface’s condition: UCVA, BCVA, Schirmer’s II test, tear break-up time (Norn’s test), OCT pachymetry of the cornea and corneal flap. The treatment effectiveness was evaluated at 1 day, 1 week, 1 and 3 months after the surgery. Results. As a result of the treatment, the following refractive data were obtained: UCVA increased from 0.09 ± 0.02 to 0.94 ± 0.07 on the first day after surgery and to 0.96 ± 0.04 and 0.99 ± 0.07 to 1 and 3 months of follow-up, BCVA respectively, from 0.97 ± 0.04 to 0.94 ± 0.07, 0.97 ± 0.07 and 0.99 ± 0.07 after surgery. A faster restoration of the cornea and corneal valve was revealed, as evidenced by a decrease in their thickness already in the 1st week after surgery in comparison with the control group, where were more pronounced changes occur only by the 1st and 3rd month of observation (p ≤ 0.05). There was a significant increase in the basal secretion of the lacrimal gland (Schirmer’s II test) from 10.16 ± 1.33 to 11.66 ± 1.13 and 12.88 ± 0.96 µm by 1 and 3 months after surgical treatment, respectively (p ≤ 0.05). The Norn’s test increased from 10.89 ± 1.94 to 12.78 ± 1.59 and 13.83 ± 0.5 s to 1 and 3 months of treatment, respectively (p ≤ 0.05). Conclusion. The effectiveness of the HILOPARIN-COMOD® use in the correction of the dry eye syndrome after keratorefractive operations has been proven. The obtained results clearly demonstrate that the HILOPARIN-COMOD® preparation enhances not only the stability of the tear film, but also the restoration of the OCT morphometric parameters of the thickness of the cornea and corneal flap.
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Crouzier, David, Vincent Dabouis, Edgar Gentilhomme, Rodolphe Vignal, Fréderic Bourbon, Florence Fauvelle, and Jean-Claude Debouzy. "Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery." Journal of Ophthalmology 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/762364.
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LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71 GHz, 50 W/m2), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1 hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering,1H-NMR HRMAS metabolomics,13C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified.
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Yingmei, Jiang, Jin Tao, Yang Xueqi, Dai Xiaoli, Jin Ri, Xu Huancai, and Wang Xiuying. "An Analysis on the Change Rule of Eyeball's Biological Parameters of Different Types in the Refraction State and Vision Before and After Refraction." Journal of Medical Imaging and Health Informatics 8, no. 9 (December 1, 2018): 1881–85. http://dx.doi.org/10.1166/jmihi.2018.2532.
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The ametropia is the most widespread eye disease for the humans. Wherein, the myopia is the commonest ophthalmological reason influencing the distant vision. The excimer laser corneal refractive surgery has always been an operation mode most widely used in myopic correction operations for a number of years. The laser assisted in-situ keratomi (LASIK) mainly transforms the frontal surface appearance of the cornea to change the corneal refraction power, and its correction effect is influenced by a great many factors such as regression and hydration of cornea. Thus, a lot of surgeons would combine own experience in conducting LASIK myopic correction. The myopic regression would affect the foreseeability, operation effect and stability of corneal refractive surgery, which results in reduction of the patients' visual quality in turn. The pathogenesis still needs further study. The change of lens thickness does not only lead to change in depth of central anterior chamber, but also would cause the change in refractive power of lens, thereby influencing the whole dioptric system of the eyeball. The previous research on postoperative regression was mostly focused on the corneal refraction, while few efforts were put in the changes of lens thickness and refractive power after LASIK.
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Hezekiah, James Deva Koresh, and Shanty Chacko. "A Review on Cornea Imaging and Processing Techniques." Current Medical Imaging Formerly Current Medical Imaging Reviews 16, no. 3 (March 2, 2020): 181–92. http://dx.doi.org/10.2174/1573405615666181204125406.
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Background: Measuring cornea thickness is an essential parameter for patients undergoing refractive Laser-Assisted in SItu Keratomileusis (LASIK) surgeries. Discussion: This paper describes about the various available imaging and non-imaging methods for identifying cornea thickness and explores the most optimal method for measuring it. Along with the thickness measurement, layer segmentation in the cornea is also an essential parameter for diagnosing and treating eye-related disease and problems. The evaluation supports surgical planning and estimation of the corneal health. After surgery, the thickness estimation and layer segmentation are also necessary for identifying the layer surface disorders. Conclusion: Hence the paper reviews the available image processing techniques for processing the corneal image for thickness measurement and layer segmentation.
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Kornilosvskiy, I. M. "Factors of Cataractogenesis in Laser Corneal Refractive Surgery." Ophthalmology in Russia 16, no. 1S (April 22, 2019): 112–17. http://dx.doi.org/10.18008/1816-5095-2019-1s-112-117.
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Purpose: to consider the main factors that stimulate cataractogenesis and the earlier development of cataracts after laser refractive surgery of the cornea. Patients and methods. The clinical material covers observations of the condition in more than 10 thousand eyes from 1 year to 20 years, after various laser refractive corneal operations (PRK, TransPRK, LASIK, FemtoLASIK). Results. Risk factors for cataractogenesis included high initial ametropia, accommodation disturbance, age, and increased external UV exposure. Clinical observations have shown that with laser correction of high degrees of ametropia, the number of cataractogenesis risk factors and their total value increased. Any laser refractive corneal surgery was accompanied by oxidative stress in all structures of the anterior eye and aseptic inflammatory response. The cornea thinning after refractive surgery increased the external UV load on the lens and created the conditions for the accumulation in it of an excessive amount of peroxide radicals. This was one of the important factors predisposing to the earlier development of cataracts. Conclusion. For clinically significant early cataract development after laser refractive corneal surgery, a combination of several cataractogenic factors is needed, such as the degree of severity of oxidative stress in the anterior eye tissue in the early postoperative period, cornea thinning, high corrective ametropia, lack of accommodation, and the patient age over 40 years old.
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Eskina, Erika N., and Victoria A. Parshina. "Results of presbyopia correction with multifocal profile application on the cornea by photorefractive keratectomy in hyperopic patients." Ophthalmology journal 10, no. 2 (May 15, 2017): 13–21. http://dx.doi.org/10.17816/ov10213-21.
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Purpose. To compare efficacy, safety and predictability of hyperopia and presbyopia simultaneous correction by photorefractive keratectomy (PRK) with application of a bi-aspheric multifocal profile on the cornea using PresbyMax software, and hyperopia correction by LASIK. Methods. 25 patients (50 eyes) of the 1st group were operated by PRK with bi-aspheric multifocal profile application on the cornea using PresbyMax software for simultaneous hyperopia and presbyopia correction. The 2nd group included 25 patients (50 eyes) operated by LASIK with aspheric profile application on the cornea for correction of hyperopia. Results. In the group 1, in one year after surgery, binocular distance uncorrected visual acuity (DUCVA) was 0.96 ± 0.16, near uncorrected visual acuity (NUCVA) - 0.77 ± 0.17, intermediate uncorrected visual acuity (IUCVA) - 0.64 ± 0.15. Visual acuity loss up to 0.2 was found in two eyes (4 %). Target refraction in the dominant eye - emmetropia - was obtained in 72% of patients; in 28% of cases, a shift up to -0.75 D was observed. Target refraction in the nondominant eye was found in 68% of patients, 12% of patients had a shift from target refraction of -0.50 D, and 20% of patients - of -0.75 D. Spherical aberration in 6 mm zone was -0.22 ± 0.17 µm. In group 2, in a year after surgery, binocular DUCVA was 1.0 ± 0.10, NUCVA - 0.37 ± 0.16, IUCVA - 0.43 ± 0.12. No monocular best corrected distance visual acuity loss was found. had myopia A clinical refraction shift from target one (emmetropia) of -0.50 D was established in 4% of patients. A spherical aberration in 6 mm zone was -0.10 ± 0.08 µm. Conclusion. PRK with bi-aspheric multifocal profile application unlike LASIK allows not only to achieve hyperopia correction but also to improve near visual acuity in patients of presbyopic age.
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Dhaliwal, Deepinder K. "Updates and Challenges in Refractive Lens Exchange." US Ophthalmic Review 11, no. 1 (2018): 17. http://dx.doi.org/10.17925/usor.2018.11.1.17.
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Refractive lens exchange (RLE) is frequently used as a refractive surgical procedure for the correction of high presbyopia and high hyperopia, for which laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK) or phakic intraocular lens (IOL) refractive surgery is unsuitable. In an expert interview, Deepinder K Dhaliwal, Professor of Ophthalmology at the University of Pittsburgh School of Medicine, Director of Cornea and Refractive Surgery at the UPMC Eye Center, and Associate Medical Director of the Charles T Campbell Ocular Microbiology Laboratory, discusses the challenges of refractive lens exchange and other aspects of refractive surgery.
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Severinsky, Boris. "Silicone Hydrogel Miniscleral Contact Lenses after Corneal Collagen Crosslinking for Post-LASIK Keratoectasia." International Journal of Keratoconus and Ectatic Corneal Diseases 3, no. 3 (2014): 127–29. http://dx.doi.org/10.5005/jp-journals-10025-1092.
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ABSTRACT Purpose To report successful visual rehabilitation of post refractive surgery keratoectasia shortly after corneal collage crosslinking (CXL) procedure achieved with silicone hydrogel mini-scleral (SHmS) contact lens. Materials and methods A 29-year-old woman attended to our clinic with complaints on decreased vision in her left eye. Twelve years earlier she underwent bilateral laser-assisted in situ keratomileusis (LASIK) procedure for myopia correction. Corneal topography revealed bilateral central keratoectasia with maximal keratometry values of 55.4 Diopter (D) for her right eye and 59.7 D for the left, corneal thicknesses were 422 and 443 respectively. The patient underwent an uneventful CXL procedure in her left eye and was fitted with SHmS lens 5 weeks later. The lens was designed to rest over the patients’ sclera and perilimbal cornea and vault the central cornea with minimal support over it. Results SHmS lens fitting resulted in significant subjective improvement in visual acuity (from 20/200, unaided to 20/25, contact lens corrected). The patient was able to wear the lens upto 10 hours a day with stable contact lens corrected vision. No contact lens related complications, such as edema or neovascularization were observed during 3 months follow-up period. As a result of successful restoration of vision in the CXL-treated eye, the patient was scheduled for the procedure in her other eye. Conclusion SHmS contact lens should be considered as an option for the visual rehabilitation of corneas shortly after collagen corneal crosslinking procedure. This novel contact lens modality made from flexible and highly gas permeable material minimizes contact lens influence on corneal recovery after CXL and provides an excellent visual outcome. How to cite this article Severinsky B. Silicone Hydrogel Mini-scleral Contact Lenses after Corneal Collagen Crosslinking for Post-LASIK Keratoectasia. Int J Kerat Ect Cor Dis 2014;3(3):127-129.
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Altinkurt, Emre, Ozkan Avci, Orkun Muftuoglu, Adem Ugurlu, Zafer Cebeci, and Kemal Turgay Ozbilen. "Logistic Regression Model Using Scheimpflug-Placido Cornea Topographer Parameters to Diagnose Keratoconus." Journal of Ophthalmology 2021 (May 18, 2021): 1–7. http://dx.doi.org/10.1155/2021/5528927.
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Purpose. Diagnose keratoconus by establishing an effective logistic regression model from the data obtained with a Scheimpflug-Placido cornea topographer. Methods. Topographical parameters of 125 eyes of 70 patients diagnosed with keratoconus by clinical or topographical findings were compared with 120 eyes of 63 patients who were defined as keratorefractive surgery candidates. The receiver operating character (ROC) curve analysis was performed to determine the diagnostic ability of the topographic parameters. The data set of parameters with an AUROC (area under the ROC curve) value greater than 0.9 was analyzed with logistic regression analysis (LRA) to determine the most predictive model that could diagnose keratoconus. A logit formula of the model was built, and the logit values of every eye in the study were calculated according to this formula. Then, an ROC analysis of the logit values was done. Results. Baiocchi Calossi Versaci front index (BCVf) had the highest AUROC value (0.976) in the study. The LRA model, which had the highest prediction ability, had 97.5% accuracy, 96.8% sensitivity, and 99.2% specificity. The most significant parameters were found to be BCVf ( p = 0.001 ), BCVb (Baiocchi Calossi Versaci back) ( p = 0.002 ), posterior rf (apical radius of the flattest meridian of the aspherotoric surface in 4.5 mm diameter of the cornea) ( p = 0.005 ), central corneal thickness ( p = 0.072 ), and minimum corneal thickness ( p = 0.494 ). Conclusions. The LRA model can distinguish keratoconus corneas from normal ones with high accuracy without the need for complex computer algorithms.
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Pinna, A., M. Salvo, S. Dore, and F. Carta. "Corneal Graft Rejection after Penetrating Keratoplasty for Keratoconus in Turner's Syndrome." European Journal of Ophthalmology 15, no. 2 (March 2005): 271–73. http://dx.doi.org/10.1177/112067210501500216.
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Purpose To report a patient with Turner's syndrome who developed graft rejection after penetrating keratoplasty (PK) for keratoconus and to review the ophthalmic literature on the association between keratoconus and Turner's syndrome. Methods A woman with bilateral keratoconus and Turner's syndrome (45,XO) was referred for progressive visual loss in the right eye. Best-corrected visual acuity was 20/400 in the right eye. Slit-lamp examination revealed corneal thinning with ectatic protrusion of the central cornea and Vogt's striae in the right eye. The patient underwent PK in the right eye in January 2001. She developed graft rejection in April 2003 and visual acuity dropped to hand motion. After treatment with topical and systemic steroids and systemic cyclosporine A, visual acuity recovered to 20/80 in July 2003. Results The authors know of only three other reported patients (six eyes) with keratoconus in Turner's syndrome. Five eyes underwent PK with good visual rehabilitation, but one developed immunologic graft rejection 7 years after surgery. On the whole, considering the current report and the other cases described in the literature, graft rejection occurred in 2 out of 6 eyes (33.3%). The graft survival rate was 80% after 2 years and 40% after 7 years. Conclusions The results suggest that grafts for keratoconus in patients with Turner's syndrome might have an increased risk of immunologic rejection. Corneal grafts in Turner's syndrome need to be monitored closely. Early detection of graft rejection and aggressive treatment with topical and systemic steroids and systemic cyclosporine A can save the graft and restore useful vision.
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Ortiz, J. P. D., C. B. S. Lisbão, F. L. C. Brito, B. Martins, and J. L. Laus. "Superficial keratectomy and 360º conjunctival flap for bullous keratopathy in a dog: a case report." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 63, no. 3 (June 2011): 773–77. http://dx.doi.org/10.1590/s0102-09352011000300036.
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A case of a two-year-old male Pinscher with a history of discomfort in the right eye was reported. The left eye had been enucleated by the referring veterinarian due to the same symptom with unsuccessful clinical treatment. The Schirmer tear test value was elevated and a decreased intraocular pressure was observed by applanation tonometry. Biomicroscopy revealed profuse corneal edema and keratoconus and fluorescein staining was negative. Gonioscopy and ophthalmoscopy did not provide any relevant data due to the corneal alterations. Bullous keratopathy was diagnosed. Surgery was performed in two steps: 1) superficial keratectomy and 360º conjunctival flap, and 2) superficial keratectomy to restore corneal transparency. Thirty days after the second superficial keratectomy, the third eyelid flap was removed. Conjunctivalization of the upper nasal quadrant of the cornea was observed. The axial portion of the cornea was transparent and vision was restored.
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Ivanova, A. V., A. S. Sklyarova, K. B. Letnikova, A. T. Khandzhyan, and N. V. Khodzhabekyan. "Simultaneous topography-guided photorefractive keratectomy with accelerated collagen cross-linking in the treatment of stage I keratoconus." Russian Ophthalmological Journal 12, no. 4 (December 12, 2019): 28–34. http://dx.doi.org/10.21516/2072-0076-2019-12-4-28-34.
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Purpose: to evaluate the efficiency of simultaneous topography-guided photorefractive keratectomy (PRK) with accelerated collagen cross-linking in the treatment of stage I keratoconus.Material and methods. 38 patients (49 eyes) aged 18 to 44 with stage I keratoconus were treated with simultaneous topography-guided PRK combined with accelerated corneal collagen crosslinking. Along with standard ophthalmological testing, patients underwent aberrometry, confocal microscopy, optical coherence tomography of the cornea, imaging of the anterior eye section on a Scheimpflug analyzer, and examination of the biomechanical properties of the cornea. The follow-up period was 2 years.Results. Two years after surgery, uncorrected visual acuity which originally was 0.23 ± 0.03 showed a statistically significant increase and reached 0.72 ± 0.02; best corrected visual acuity improved from 0.44 ± 0.03 to 0.89 ± 0.02; the refractive power of the cornea fell from 45.03 ± 0.28 to 42.55 ± 0.31 D; the spherical component of refraction reduced from -2.00 ± 0.19 to -0.73 ± 0.09 D; the cylinder component reduced from 2.46 ± 0.14 to 0.79 ± 0.07 mm, the thinnest point of the cornea reduced from 486.30 ± 4.78 to 406.80 ± 6.51 μm. The highest order aberrations showed the following results: Coma index reduced from 0.27 ± 0.12 to 0.08 ± 0.07, Tilt reduced from 0.53 ± 0.11 to 0.10 ± 0,09, and Trefoil reduced from 0.13 ± 0.04 to 0.05 ± 0.02.Conclusion. The analysis of clinical and functional results, biomechanical properties and structures of the cornea confirmed the efficacy and safety of the combined treatment of patients with stage I keratoconus.
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Obraztsova, M. R., I. A. Mushkova, and N. V. Maychuk. "Application of the method of accelerated ultraviolet crosslinking of corneal collagen using a customized protective contact lens without an ultraviolet filter in a patient with secondary keratoectasia after Lasik (a clinical case)." Modern technologies in ophtalmology, no. 2 (June 15, 2021): 71–74. http://dx.doi.org/10.25276/2312-4911-2021-2-71-74.
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Purpose. To evaluate the clinical and functional results of the technique of ultraviolet crosslinking on the thin cornea using a customized soft contact lens without an ultraviolet filter in a patient with secondary corneal ectasia. Material and methods. Under observation was patient S., 32 years old, diagnosed with secondary keratoectasia of the left eye after LASIK surgery, performed in 2008 for moderate myopia. To stabilize the keratectatic process, complicated by the presence of a thin cornea with a thickness of less than 400 microns, an operation was performed: ultraviolet crosslinking of corneal collagen using a customized protective lens without an ultraviolet filter. Results. There were no complications during and after the operation. According to keratorefractometry and keratotopography, there was no progression of the disease after surgery, and no loss of endothelial cells was detected. Conclusion. Thus, conducting ultraviolet crosslinking of corneal collagen using a protective customized lens without an ultraviolet filter is a promising technique that allows you to achieve stabilization of the keratectatic process. Key words: corneal ectasia, thin cornea, UV crosslinking, customized lens.
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Pradhan, Asik, Kishore Raj Pradhan, Gauri Shankar Shrestha, Purushottam Dhunganga, and Raju Kaiti. "Contrast sensitivity before and after small incision lenticule extraction and femtosecond laser in situ keratomileusis." Asian Journal of Ophthalmology 16, no. 4 (November 23, 2019): 284–92. http://dx.doi.org/10.35119/asjoo.v16i4.417.
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Introduction: Contrast sensitivity function after laser ablation of the cornea in refractive surgery is an important tool for measuring quality of visual function. The effect of small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK) on visual function can be compared by measuring spatial contrast sensitivity.
Purpose: This study was to compare contrast sensitivity function in patients undergoing refractive surgery for myopia at Tilganga Institute of Ophthalmology.
Methods: In a retrospective study, 15 subjects who underwent refractive surgeries comprising 9 cases of SMILE and 6 cases of FS-LASIK at Tilganga Eye Hospital were enrolled in the study. A major assessment included best corrected monocular contrast sensitivity with functional vision analyzer at spatial frequencies of 1.5, 3, 6, 12, and 18 cycles/deg in photopic condition (85 cd/m2) before, 3 months, and 1 year after the surgery. The average functional acuity contrast test scores for each spatial frequency were recorded. Differences between preoperative and postoperative contrast sensitivity at each spatial frequency were analyzed through parametric paired Student’s t-test.
Results: Contrast sensitivity of postoperative FS-LASIK and SMILE did not differ from preoperative values at a photopic level. However, at high spatial frequency (12 and 18 cycles/deg), contrast sensitivity function improved significantly (p < 0.05) in eyes after FS-LASIK. Eyes after SMILE surgery did not show any reduction in contrast sensitivity at all the spatial frequencies.
Conclusion: Under photopic conditions, the contrast sensitivity function is unaffected by SMILE or FS-LASIK.
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Kalkan Akcay, Emine, Murat Akcay, Betul Seher Uysal, Pinar Kosekahya, Abdullah Nabi Aslan, Mehtap Caglayan, Cemal Koseoglu, Fatma Yulek, and Nurullah Cagil. "Impaired Corneal Biomechanical Properties and the Prevalence of Keratoconus in Mitral Valve Prolapse." Journal of Ophthalmology 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/402193.
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Objective. To investigate the biomechanical characteristics of the cornea in patients with mitral valve prolapse (MVP) and the prevalence of keratoconus (KC) in MVP.Materials and Methods. Fifty-two patients with MVP, 39 patients with KC, and 45 control individuals were recruited in this study. All the participants underwent ophthalmologic examination, corneal analysis with the Sirius system (CSO), and the corneal biomechanical evaluation with Reichert ocular response analyzer (ORA).Results. KC was found in six eyes of four patients (5.7%) and suspect KC in eight eyes of five patients (7.7%) in the MVP group. KC was found in one eye of one patient (1.1%) in the control group (P=0.035). A significant difference occurred in the mean CH and CRF between the MVP and control groups (P=0.006andP=0.009, resp.). All corneal biomechanical and topographical parameters except IOPcc were significantly different between the KC-MVP groups (P<0.05).Conclusions. KC prevalence is higher than control individuals in MVP patients and the biomechanical properties of the cornea are altered in patients with MVP. These findings should be considered when the MVP patients are evaluated before refractive surgery.
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Maslennikov, Vyacheslav Igorevich, Sergey Alekseyevich Koskin, Yuriy Yevgenyevich Shelepin, and Aleksandr Vladimirovich Yan. "A corneal surface study in patients after laser keratomilesis." Ophthalmology journal 6, no. 3 (September 15, 2013): 32–36. http://dx.doi.org/10.17816/ov2013332-36.
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The cornea of the human eye is not only refracts the light, but also acts as a convex mirror, which reflects the surroundings. In ophthalmology, an image reflected by its anterior surface is known as the 1st Purkinje image. Characteristics of this image are determined by the properties of the light source and the state of corneal surface. At the present time, there are many methods in ophthalmology to study various properties of the cornea, but most of them either require expensive equipment or are qualitative and not informative. Meanwhile, a “shining” characteristic of the cornea in general is assessed subjectively and is not properly addressed in the ophthalmic literature. Our work was conducted to study the possibility of applying the method of measuring the reflective ability of the cornea to measure the state of its anterior surface. Our study involved men and women aged 18–45 years after laser-assisted in situ keratomilesis (LASIK). With our new method of measuring the corneal reflectance, we investigated patients before surgery, day 1 post-op and after 1 week. Each study case included a measurement of the reflectivity of the cornea after blinking, and after 15 sec. We found that on the day 1 after surgery corneal reflectivity increases, at the same time, 15 sec after blinking it is reduced to normal. This suggests a reduction of the tear film stability and that the patients had some symptoms of corneal syndrome, and as a consequence, increased tear production. One week after surgery, we observed a different picture: the reflective power of the cornea decreased. We consider this to be a sign of corneal nerves damage and decreased tear production.
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Ioshin, I. E. "Phacoemulsification and calculation of intraocular lenses in patients given keratorefractive surgery. Part 1." Russian Ophthalmological Journal 14, no. 2 (June 20, 2021): 55–58. http://dx.doi.org/10.21516/2072-0076-2021-14-2-55-58.
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Rationale.Qualitative rehabilitation of patients with cataracts who had keratorefractive surgeries depends on phacoemulsification technology and correctly calculated optical power of the IOL. Purpose: present the author’s own approaches to the development of surgical tactics for treating patients with cataracts who underwent keratorefractive surgeries. Material and methods. The complicated character of cataract surgery performed after LASIK — deterioration of visualization due to the presence of an optical ablation zone and a transition zone (6–7 mm) — is successfully compensated by instillations of a dispersed viscoelastic (methylcellulose) onto the surface of the cornea. Another factor is the deepening of the anterior chamber in high myopia, which is uncomfortable for manipulation and may require a lowerlevel of irrigation (up to 60 mm Hg). The technology of surgery performed after radial keratotomy (RK) requires utmost attention to the prevention of surgical astigmatism that could emerge due to biomechanical instability of the cornea. To ensure such prevention, paracentesis is performed outside the zone of keratotomy scars, the main 2.2 mm incision is made after capsulorhexis in the sclerolimbal zone, and at theend of the operation, a subconjunctival injection is performed in the conjunctival zone of the knife keratom entrance for the tamponade ofthe outer part of the incision without suturing. These techniques made it possible to successfully perform more than 200 operations and achieve a favorable course of the postoperative period from the first day. Fast adaptation of the incision (1–2 days), uncomplicated course of the postoperative period and the absence of induced astigmatism are important advantages of this technology. Conclusion. The choice of surgical technology, taking into account the initial state of the eye after LASIK and RK surgeries, is an important task. Yet the main problem with which the doctor is faced after keratorefractive surgery is the difficulty of calculating the optical power of the IOL which must take into account the special needs of the patient with a particular refractive history, which will be reported in part 2 of the article.
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Dehghan, Behrouz, Mohammadnaeem Aminifard, and Zahra Raisi. "Analysis of causes and outcomes of corneal transplantation in al-zahra eye hospital in southeast of Iran from 2011-2016." International Journal of Research in Medical Sciences 5, no. 7 (June 24, 2017): 2917. http://dx.doi.org/10.18203/2320-6012.ijrms20172598.
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Background: Corneal transplantation is known as the most successful and common type of organ transplant, but it calls for more intensive and long-term care. Given the lack of adequate information on this important surgery in this province and the differences between indications and causes of corneal transplantation, the present research was carried out to examine the causes and outcomes of corneal transplant in patients visiting Al-Zahra eye hospital who had received donated cornea in the past five years.Methods: In a retrospective analytical-descriptive study 135 files of 149 eyes that had gone through corneal transplantation were examined. Information on the age, gender, residence, indications, and surgery consequences was extracted and was analyzed in SPSS 19 statistical software with descriptive statistics (percentage, frequency, mean, and standard deviation.Results: The highest transplant indication was keratoconus with a frequency of 39.9% followed by bullous keratopathy, corneal opacity, and transplant rejection with frequencies of 16.1, 12.7, and 10.1%, respectively. Other indications were corneal scar (9.4%), corneal perforation (2.7%), trauma (2.7%), and Fuchs’ corneal dystrophy (1.3%) in the order mentioned. Concerning postoperative complications in this research, 57.7% of the eyes (86 cases) showed no complication. Moreover, complications were mostly related to astigmatism with a frequency of 30.8% (46 cases).Conclusions: In general, the most common indication in this research was keratoconus. Most surgeries were also complication-free and most complications were associated with astigmatism.
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Jiang, Xue. "Deterioration of Avellino corneal dystrophy in a Chinese family after LASIK." International Journal of Ophthalmology 14, no. 6 (June 18, 2021): 795–99. http://dx.doi.org/10.18240/ijo.2021.06.02.
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AIM: To reveal the importance of TGFBI gene screening for candidates with a family history of corneal disease or granular opacities in corneal stroma before refractive surgery. METHODS: A 37-year-old male (proband) underwent bilateral laser-assisted in situ keratomileusis (LASIK) in 2002, with right vision decreased significantly in 2006. The proband and other 32 members of the family underwent a detailed ophthalmic examination, including vision acuity, intraocular pressure, slit-lamp photograph, fundus examination, optical coherence tomography (OCT) of cornea, and in vivo confocal microscope (IVCM) and peripheral blood was used for genomic DNA extraction. Seventeen TGFBI gene exons were analyzed via polymerase chain reaction amplification and direct sequencing. RESULTS: Slit-lamp, IVCM, and OCT images showed that a large amount of dense and confluent granular opaque were seen at the interfaces of the flap and remnant stromal bed in right and light degree in left eye. Sanger sequencing showed that there was a 371G>A mutation (CGC>CAC) in exon 4, which indicated that he harbored a heterozygote R124H mutation, identifying the diagnosis of Avellino corneal dystrophy (ACD). Among the other 32 family members, 6 of them harbored the identical mutation to that in the proband. CONCLUSION: ACD will worsen and recur after LASIK. Preoperative gene-screening for TGFBI mutations is important in diagnosing ACD.
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Shaker, Lina M., Ahmed A. Al-Amiery, Abdul Amir H. Kadhum, and Mohd S. Takriff. "Manufacture of Contact Lens of Nanoparticle-Doped Polymer Complemented with ZEMAX." Nanomaterials 10, no. 10 (October 15, 2020): 2028. http://dx.doi.org/10.3390/nano10102028.
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Many people suffer from myopia or hyperopia due to the refractive errors of the cornea all over the world. The use of high refractive index (RI), Abbe number (νd), and visible light transmittance (T%) polymeric contact lenses (CLs) holds great promise in vision error treatment as an alternative solution to the irreversible laser-assisted in situ keratomileusis (LASIK) surgery. Titanium dioxide nanoparticles (TiO2 NPs) have been suggested as a good candidate to rise the RI and maintain high transparency of a poly(methyl methacrylate) (PMMA)-TiO2 nanocomposite. This work includes a preparation of TiO2 NPs using the sol gel method as well as a synthesis of pure PMMA by free radical polarization and PMMA-TiO2 CLs using a cast molding method of 0.005 and 0.01 w/v concentrations and a study of their effect on the aberrated human eye. ZEMAX optical design software was used for eye modeling based on the Liou and Brennan eye model and then the pure and doped CLs were applied. Ocular performance was evaluated by modulation transfer function (MTF), spot diagram, and image simulation. The used criteria show that the best vision correction was obtained by the CL of higher doping content (p < 0.0001) and that the generated spherical and chromatic aberrations in the eye had been reduced.
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Osipyan, G. A., and Kh Khrayst. "Possibilities of Intralamellar Keratoplasty in Rehabilitation of Keratoconus Patients." Ophthalmology in Russia 16, no. 2 (June 30, 2019): 169–73. http://dx.doi.org/10.18008/1816-5095-2019-2-169-173.
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Keratoconus is one of the topical problems in modern ophthalmology. Among the currently used treatment methods is intralamellar keratoplasty that utilizes allomaterials or homotransplants. The surgery technique has obvious advantages over penetrating and deep anterior lamellar keratoplasty. There is no risk of tissue incompatibility, the recovery period is shorter, and prolonged use of corticosteroids is not necessary. In recent years, technological development has made the application of femtosecond laser a standard procedure for various surgical interventions on the cornea, particularly for creation of intrastromal tunnels and corneal bags. This article presents an analysis of the modern literature data about different intralamellar keratoplasty techniques for treatment of keratoconus. The described techniques show its great clinical possibilities, especially the intrastromal keratoplasty variant with implantation of biological tissues. One of such techniques was developed and tried by a group of specialists at Research Institute of Eye Diseases in 2014. It involves recovery of corneal thickness in the ectatic area by intralamellar transplantation of a layered transplant of adequate size, which acts as a bandage. The surgery simultaneously affects the stabilization action, corrects refractive errors and eliminates the structural changes; it was accordingly named bandage therapeutic-optical keratoplasty (BTOK). The indication for its usage is progressing keratoconus in stage II–III patients. Among the described outcomes are cease of the disease progression in long-term follow-up, improvement of corrected and uncorrected visual acuity. The foreign analogue of the technique is Corneal Allogenic Intrastromal Ring Segments (CAIRS) by Jacob S. et al. His study included 20 patients with stages I to IV keratoconus; all patients undergone corneal cross-linking as the first stage, then they had CAIRS implanted into the intrastromal tunnels prepared with femtosecond laser. In both methods, the authors point at the improvement of corrected and uncorrected visual acuity. None of the patients had implant dislocation or keratoconus progression during the follow-up period.
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Reis, José RC, Alberto Diniz-Filho, and Fábio M. Rocha. "Pathogenesis of Fixed Dilated Pupil (Urrets-Zavalía Syndrome) after Deep Lamellar Keratoplasty in Keratoconus." International Journal of Keratoconus and Ectatic Corneal Diseases 5, no. 1 (2016): 32–34. http://dx.doi.org/10.5005/jp-journals-10025-1118.
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ABSTRACT Purpose To present a case series of patients that developed Urrets-Zavalia syndrome (UZS) after deep anterior lamellar keratoplasty (DALK) for treating keratoconus and discuss the mechanisms for the syndrome. Materials and methods Retrospective chart analysis of patients who developed UZS after DALK at the Cornea Unit, Hospital São Geraldo, Federal University of Minas Gerais. Results We present a series of 3 patients with features consistent with UZS, after undergoing DALK. Elevated intraocular pressure (IOP) was noted in the early postoperative period in 2 cases, despite the fact that the other case reported eye pain, headache, and nausea at the night after the surgery with undocumented IOP. Although at different extents, the pupil remained atrophic and dilated in all 3 eyes, and 2 of them developed anterior subcapsular cataract. Conclusion Iris ischemia resulting from occlusion of iris root vessels due to elevated IOP higher than diastolic blood pressure causes UZS. Elevated IOP should be monitored, especially in young patients with low diastolic blood pressure, in order to avoid the occurrence of the syndrome. How to cite this article Reis JRC, Diniz-Filho A, Rocha FM, Torquetti L. Pathogenesis of Fixed Dilated Pupil (Urrets-Zavalía Syndrome) after Deep Lamellar Keratoplasty in Keratoconus. Int J Kerat Ect Cor Dis 2016;5(1):32-34.
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Kalinnikov, Yu Yu, N. P. Sobolev, S. V. Novikov, A. V. Zinov’eva, and D. V. Nevrov. "Clinical and Functional Outcomes of Lens-Iris Diaphragm Implantation with Simultaneous Subtotal Penetrating Keratoplasty: a 15-Year Follow-Up Case Report." Ophthalmology in Russia 16, no. 1 (March 30, 2019): 102–8. http://dx.doi.org/10.18008/1816-5095-2019-1-102-108.
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Combined traumatic injuries of the anterior eye segment are attributed to the severe consequences of the injured organ of vision. Iris defects result in spherical and chromatic aberrations, diplopia, flares, severe photophobia, cosmetic defects, and significantly reduced visual acuity after the injury. The literature describes various methods to restore visual functions impaired as a result of aniridia. Use of an artificial iris together with an intraocular lens pathology results in optimal reconstruction and recovery of normal anterior segment anatomy and topography. In this paper, we provide a report on a patient followed up for 15 years after combined reconstruction eye surgery for an off-the-job penetrating eye injury sustained in 2003. A complex intervention was required due to the involvement of the cornea, iris, and lens. In 2004, the patient underwent a lens-iris diaphragm implantation combined with penetrating keratoplasty. The diaphragm implantation was followed by an improvement in visual acuity and elimination of photophobia and flares. There were no intra- or postoperative complications. Two years later, LASIK refractive surgery was performed on the corneal transplant to eliminate induced ametropia. The patient retained good eye function, with a stable position of the lens-iris diaphragm, for many years after the diaphragm implantation, keratoplasty, and refractive surgery. In 2018, he had an intravitreal implant impregnated with dexamethasone, as changes in the retina had developed. The long-term follow-up in this case demonstrates that the implantation of a lens-iris diaphragm resulted in an elimination of undesirable optical events associated with aniridia and produced an optimal functional result, while also improving the patient’s quality of life with a good aesthetic effect.
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Chuprov, A. D., Yu V. Kanyukova, and A. E. Voronina. "On the Possibility of Expanding Indications for Refractive Correction of Ametropia (4 Clinical Cases)." Ophthalmology in Russia 15, no. 2S (July 28, 2018): 174–78. http://dx.doi.org/10.18008/1816-5095-2018-2s-174-178.
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Refractive surgery is a dynamically developing field of ophthalmic surgery, which requires studying new approaches for determining indications and contraindications for refractive surgery.Purpose. To investigate the possibility of expanding indications for refractive surgery in conditions related to contraindications on the example of four clinical cases.Material and methods. The study included 4 clinical cases of photorefractive operations in patients with relative contraindications who underwent refractive surgery (Femto-Lasik, photorefractive keratectomy (PRK), phototherapeutic keratectomy (PTK)).Results and discussion. Follow-up period of patients after Femto-Lasik, PRK and PTK was 1 year. During this period, stabilization of such parameters as intraocular pressure (IOP), progression of diabetic retinopathy, visual acuity was detected on all operated eyes. There were no postoperative complications. In the first clinical example, to avoid flap injury pneumotonometry was performed 72 hours after the surgery. IOP indices differed from preoperative ones and were 15 mm Hg because of the flap cut and the removal of part of the corneal tissue as a result of laser ablation. In the second clinical example, BCVA OU was 1.0 throughout the whole follow-up period. In the third clinical example recurrence of retinal detachment and any formations of new zones of peripheral vitreochorioretinal were not observed. BCVA improved up to 0.9–1.0. In the fourth clinical example, 3 months later, the patient complained for “misting” in the right eye. On examination, subepithelial fibroplasia of the 1st degree was revealed. After the course of treatment, the transparency of the cornea was restored. The data of the diagnostic examination after the surgery at the period of 1 month, 3 months did not differ and corresponded to preoperative ones. Diagnostic examination data 1 year after the operation: visual acuity: OD — 1.0; OS — 0.4 sph + 1.0Dcyl + 1.5Dax 45 = 0.8.Conclusion. The presented clinical examples allow us to reconsider the list of relative contraindications for performing refractive operations for compensated diabetes mellitus, glaucoma, retinal detachment, corneal opacities, as it can be performed safely and effectively with good refractive results.
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Stroyko, M. S., S. V. Kostenev, and A. L. Pakhomova. "Сorrection of Corneal Astigmatism in Patients with a Thin Cornea by Improved Combined Technology." Ophthalmology in Russia 15, no. 2S (July 28, 2018): 166–73. http://dx.doi.org/10.18008/1816-5095-2018-2s-166-173.
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Purpose:to carry out an advanced combined technology, including femtosecond astigmatic keratotomy and topographically-oriented photorefractive keratectomy in order to correct corneal astmigmatism in patients with a thin cornea. Presentation and evaluation of the results of this observation.Patients and methods. There are data of 19 patients (30 eyes) with complex myopic astigmatism combined with a thin cornea who received the operation of femtosecond astigmatic keratotomy (the first stage of an improved combined technology). Mean values before surgery: sph –4.1 ± 2.1 (from –0.3 to –7.8) D, cyl –4.9 ± 1.4 (–3.0 to –7.3) D, UDVA 0.1 ± 0.05 (from 0.01 to 0.2) of the rows of table, CDVA 0.6 ± 0.1 (from 0.4 to 0.9) of the rows of table, Kmax 46.70 ± 1.1 (from 44.50 to 48.50), Kmin 42.8 ± 1.3 (from 40.00 to 44.00), the thickness of the cornea is 470.0 ± 12.7 (from 4470 to 495.0) μm. The second stage: topographically oriented photorefractive keratectomy was performed to the same patients with the aim of correcting residual ametropy. Mean values before surgery: sph –5.3 ± 2.0 (from –1.8 to –8.8) D, cyl –1.6 ± 0.8 (from –0.5 to –3.0) D, UDVA 0.3 ± 0.1 (from 0.1 to 0.6) rows of the table, CDVA 0.7 ± 0.1 (from 0.5 to 0.9) rows of the table, Kmax 46.70 ± 1.1 (from 44.50 to 48.50), Kmin 42.8 ± 1.3 (from 40.00 to 44.00), the thickness of the cornea 464.3 ± 8.3 (from 460.0 to 485.0). All patients from the study received a diagnostic examination by standard and special methods based on the S. Fyodorov Eye Microsurgery State Institution, a screening of the keratoconus on the scanning topograph Pentacam HR “Oculus Optikgerate GmbH”, Germany was carried out. The first stage of the advanced combined technology was used the LenSx Laser (“Alcon”, USA), the second stage — WaveLight EX-500 (“Alcon”, USA), was used.Results. After the completion of two stages of improved combined technology the following results were obtained: reduction of the sph with –4.1 ± 2.1 (from –7.8 to –0.3) to –0.4 ± 0.3 (from –1.0 to 0.0), cyl with –4.9 ± 1.4 (from –7.3 to –3.0) to –0.1 ± 0.1 (from –0.5 to 0.0), Kmax from 44.70 ± 1.1 (from 44.50 to 48.50) to 37.8 ± 1.6 (from 36.00 to 43.00), Kmin 42.80 ± 1.3 (from 40.00 to 44.00) to 37.00 ± 1.3 (from 36.00 to 40.00), CDVA growth with 0.6 ± 0.l (from 0.4 to 0.9) to 0.8 ± 0.1 (from 0.5 to 1.0), UDVA from 0.1 ± 0.05 (from 0.01 to 0.2) to 0.7 ± 0.1 (from 0.4 to 0.9).Conclusion. The improved combining technology, including femtosecond astigmatic keratotomy and topographically — oriented photorefractive keratectomy is effective and safety technology, allowing to correct of corneal astigmatism in patients with a thin cornea.
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Pérez-Cambrodí, Rafael J., and Pedro Ruiz-Fortes. "Reverse Geometry Hybrid Contact Lens Fitting in a Case of Donor-Host Misalignment after Keratoplasty." International Journal of Keratoconus and Ectatic Corneal Diseases 2, no. 2 (2013): 69–72. http://dx.doi.org/10.5005/jp-journals-10025-1054.
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ABSTRACT Purpose To report the successful outcome obtained after fitting a new hybrid contact lens in a cornea with an area of donor-host misalignment and significant levels of irregular astigmatism after penetrating keratoplasty (PKP). Materials and methods A 41-year-old female with bilateral asymmetric keratoconus underwent PKP in her left eye due to the advanced status of the disease. One year after surgery, the patient referred a poor visual acuity and quality in this eye. The fitting of different types of rigid gas permeable contact lenses was performed, but with an unsuccessful outcome due to contact lens stability problems and uncomfortable wear. Scheimpflug imaging evaluation revealed that a donor-host misalignment was present at the nasal area. Contact lens fitting with a reverse geometry hybrid contact lens (Clearkone, SynergEyes Carlsbad) was then fitted. Visual, refractive, and ocular aberrometric outcomes were evaluated during a 1-year period after the fitting. Results Uncorrected distance visual acuity improved from a prefitting value of 20/200 to a best corrected postfitting value of 20/20. Prefitting manifest refraction was +5.00 sphere and .5.50 cylinder at 75°, with a corrected distance visual acuity of 20/30. Higher order root mean square (RMS) for a 5 mm pupil changed from a prefitting value of 6.83 μm to a postfitting value of 1.57 μm (5 mm pupil). The contact lens wearing was referred as comfortable, with no anterior segment alterations. Conclusion The SynergEyes Clearkone contact lens seems to be another potentially useful option for the visual rehabilitation after PKP, especially in cases of donor-host misalignment. How to cite this article Pérez-Cambrodí RJ, Ruiz-Fortes P, Llorens DPP. Reverse Geometry Hybrid Contact Lens Fitting in a Case of Donor-Host Misalignment after Keratoplasty. Int J Kerat Ect Cor Dis 2013;2(2):69-72.
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Mashige, K. P. "A review of corneal diameter, curvature and thickness values and influencing factors*." African Vision and Eye Health 72, no. 4 (December 12, 2013). http://dx.doi.org/10.4102/aveh.v72i4.58.
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The cornea is an important ocular structure involved in the mediation of visual perception. It is the principal refractive surface of the eye and vision can be significantly affected by relatively small changes in its structure and parameters. Measurement of corneal parameters is important in the diagnosis and management of ocular diseasessuch as keratoconus and glaucoma, and also in the fitting of contact lenses or with refractive surgery such as Laser-Assisted in situ Keratomileusis(LASIK) and photorefractive keratectomy (PRK). The human corneal diameter, anterior curvature and centre thickness as well as factors influencing them are reviewed in this article. This review will be useful to eye care professionals who routinely measure these parameters when fitting contact lenses and assessing, diagnosing as well as managing corneal and other ocular conditions. (S Afr Optom 2013 72(4) 185-194)
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"BEYOND PSEUDO-ACCOMODATIVE CORNEA LASIK (PAC LASIK). A PERSONAL INSIGHT." International Journal of Case Reports, 2021, 200. http://dx.doi.org/10.28933/ijcr-2021-01-3005.
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Laser in-situ keratomieleusis (LASIK) is a common intervention for young, active, ametropic individuals to improve their visual acuity. pseudo-accommodative cornea (PAC), a variant of LASIK, to correct ametropia among presbyopic patients is proven in maintaining good distant vision; yet, the satisfactory spectacle free reading vision is limited to the ageing progression. However, successful treatments do not guarantee patient’s satisfaction. Assesment of the objective topographic indicators, visual acuity, higher order abrasion, and contrast sensitivity; revealed the clarification of a mild headache as a personal subjective experience after the treatment. The role of the persistent, dominant eye, the brain perception, seems to be critical factor to a patient’s satisfaction. To a certain degree, the interplay amongst the optical part and it’s supporting tissue, within and between the eyeballs, as well as its relationship to the neurosensory parts of the visual systems after Lasik surgery have not yet been assessed and reported elsewhere.
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Cruz, Giovanna Karinny Pereira, Isabelle Campos de Azevedo, Diana Paula de Souza Rego Pinto Carvalho, Allyne Fortes Vitor, Viviane Euzébia Pereira Santos, and Marcos Antonio Ferreira Júnior. "Clinical and epidemiological aspects of cornea transplant patients of a reference hospital." Revista Latino-Americana de Enfermagem 25 (2017). http://dx.doi.org/10.1590/1518-8345.1537.2897.
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ABSTRACT Objective: clinically characterizing cornea transplant patients and their distribution according to indicated and post-operative conditions of cornea transplantation, as well as estimating the average waiting time. Method: a cross-sectional, descriptive and analytical study performed for all cornea transplants performed at a reference service (n=258). Data were analyzed using Statistical Package for the Social Sciences, version 20.0. Results: the main indicator for cornea transplant was keratoconus. The mean waiting time for the transplant was approximately 5 months and 3 weeks for elective transplants and 9 days for urgent cases. An association between the type of corneal disorder with gender, age, previous surgery, eye classification, glaucoma and anterior graft failure were found. Conclusion: keratoconus was the main indicator for cornea transplant. Factors such as age, previous corneal graft failure (retransplantation), glaucoma, cases of surgeries prior to cornea transplant (especially cataract surgery) may be related to the onset corneal endothelium disorders.
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Kato, Naoko, Takeshi Ide, Hidenaga Kobashi, and Ikuko Toda. "Infectious keratitis after corneal crosslinking for keratoconus caused by levofloxacin-resistant microorganisms." BMC Ophthalmology 21, no. 1 (August 31, 2021). http://dx.doi.org/10.1186/s12886-021-02081-4.
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Abstract Introduction We present seven cases of infectious keratitis after corneal crosslinking (CXL) to attenuate keratoconus progression. Methods Of 524 consecutive patients who underwent CXL, 7 cases (4 males and 3 females; 21.5 ± 7.1 years) developed postoperative infectious keratitis were retrospectively reviewed. CXL was performed using the Dresden protocol or an accelerated protocol involving epithelial removal. Results All cases appeared normal on the day after surgery, but subsequently developed eye pain, blurred vision, corneal infiltration, inflammation of the anterior chamber, and ciliary injection on day 2 or 3. Methicillin-resistant Staphylococcus aureus was cultured from two eyes, methicillin-sensitive Staphylococcus aureus from two eyes, and Streptococcus pneumoniae from one eye. All detected bacteria were resistant to levofloxacin (LVFX). Five of the seven cases, especially four of the five severe cases with hypopyon, had a history of atopic dermatitis. All cases were observed after 2015. Conclusions Infectious keratitis after CXL caused by microbes resistant to LVFX is increasing. In addition to careful postoperative observation of the cornea, preoperative evaluation of bacteria within the conjunctival sac evident on nasal swab cultures may be useful to identify potentially problematic microbes and inform the selection of appropriate antibiotics.
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Roy, Abhijit Sinha, and William J. Dupps. "Patient-Specific Modeling of Corneal Refractive Surgery Outcomes and Inverse Estimation of Elastic Property Changes." Journal of Biomechanical Engineering 133, no. 1 (December 22, 2010). http://dx.doi.org/10.1115/1.4002934.
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The purpose of this study is to develop a 3D patient-specific finite element model (FEM) of the cornea and sclera to compare predicted and in vivo refractive outcomes and to estimate the corneal elastic property changes associated with each procedure. Both eyes of a patient who underwent laser-assisted in situ keratomileusis (LASIK) for myopic astigmatism were modeled. Pre- and postoperative Scheimpflug anterior and posterior corneal elevation maps were imported into a 3D corneo-scleral FEM with an unrestrained limbus. Preoperative corneal hyperelastic properties were chosen to account for meridional anisotropy. Inverse FEM was used to determine the undeformed corneal state that produced <0.1% error in anterior elevation between simulated and in vivo preoperative geometries. Case-specific 3D aspheric ablation profiles were simulated, and corneal topography and spherical aberration were compared at clinical intraocular pressure. The magnitude of elastic weakening of the residual corneal bed required to maximize the agreement with clinical axial power was calculated and compared with the changes in ocular response analyzer (ORA) measurements. The models produced curvature maps and spherical aberrations equivalent to in vivo measurements. For the preoperative property values used in this study, predicted elastic weakening with LASIK was as high as 55% for a radially uniform model of residual corneal weakening and 65% at the point of maximum ablation in a spatially varying model of weakening. Reductions in ORA variables were also observed. A patient-specific FEM of corneal refractive surgery is presented, which allows the estimation of surgically induced changes in corneal elastic properties. Significant elastic weakening after LASIK was required to replicate clinical topographic outcomes in this two-eye pilot study.