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1
Plummer, Robert. "Livingstone's cataract". Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/12236.
Testo completoAbstract (sommario):
Includes abstract.In January 1860, the painter Thomas Baines returned to Cape Town in disgrace, having been dismissed from David Livingstone's expedition to explore the Kebrabasa rapids on the Zambesi River. Livingstone's Cataract is a historical novel that follows Baines's involvement with the expedition. It is written from Baines's point of view, in the first person...
2
Ndlovu, Keeleditse. "Perceptions of cataracts and cataract services of elderly persons in Mathangwane, Botswana". Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/26621.
Testo completoAbstract (sommario):
Background: Cataract is the leading cause of blindness globally. In Botswana about 60% of blindness is due to cataract. Health services in Botswana are free, as are cataract services. Despite the free health services offered, the Batswana do not fully utilize the available eye care services especially the cataract services. Many Batswana access health care in public hospitals, where patients may have to wait for long periods for clinic appointments and surgery. Research question: What are the perceptions that elderly persons in Mathangwane village in Botswana, have of cataracts and cataracts services? Aim: To explore and describe the perceptions of elderly persons in Mathangwane about cataracts and cataract services. Objectives: 1. Explore and describe elderly persons' perceptions of cataracts; 2. Explore and describe elderly persons' perceptions of cataract services; 3. Explore reasons for use and non-use of current cataract services. Methods: Qualitative exploratory descriptive methods were used. A qualitative study design with purposeful sampling was used to identify participants for interviews and focus group discussion. Semi-structured interviews with seven participants aged sixty-five years and older with diagnosed cataract as well as a focus group with six of the seven participants were conducted. Data was analysed using a content analysis approach. Results: Five themes emerged from the interviews and a focus group discussion: i. Cataract as the 'spider web'; ii. Curing cataract with traditional herbs; iii. Cataract a problem of the elderly caused by modem food; iv. The burden of cataract blindness: 'mealie on the fire'; v. The ambivalent voice of elderly persons about cataract services. Conclusion: Findings from this study show that the participants had a general understanding of what cataract is and they had a particular description for this. Both positive and negative feelings were expressed in relation to the services available. Although cataract surgery was perceived to restore vision a major concern of the elderly persons was in relation to delays they experienced while waiting for the cataract to fully mature. Despite the free services offered at community level there is a great need for affordable and accessible transportation services for elderly persons utilising the cataract services.
3
Hanna, Keith James. "Monitoring cataract change". Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302892.
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Zanetti, Fernando Roberte 1983. "Efeito dos antiinflamatórios tópicos acetato de prednisolona 1%, nepafenaco 0.1% e cetorolaco de trometamina 0.4% na manutenção da midríase intra-operatória em facectomias = estudo clínico aleatorizado". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311825.
Testo completoAbstract (sommario):
Orientadores: Rodrigo Pessoa Cavalcanti Lira, Carlos Eduardo Leite ArietaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Introdução: Os Antiinflamatórios tópicos são utilizados comumente no tratamento da inflamação ocular e do edema macular cistóide relacionado a cirurgia de catarata. Tem sido sugerido o uso de antiinflamatórios antes da cirurgia, para conseguir uma melhor midriase intraoperatória. Foi relatado que quando midriase e maior do que 6 mm, a incidência de ruptura da cápsula posterior e reduzido pela metade. O objetivo deste estudo original foi comparar o efeito do uso pré-operatório do acetato de prednisolona, do cetorolaco de trometamina, do nepafenaco e de um placebo, na manutenção da midriase intra-operatória da cirurgia de catarata. Objetivo: Comparar o efeito do uso pré-operatório dos antiinflamatórios tópicos acetato de prednisolona 1%, nepafenaco 0.1% e cetorolaco de trometamina 0.4%, alem de um placebo, na manutenção da midriase intraoperatoria durante a cirurgia de catarata. Desenho: Ensaio clinico aleatorizado, mascarado, realizado em um único centro. Métodos: E um estudo composto por 140 pacientes submetidos a cirurgia de facoemulsificação de catarata. Os pacientes (35 voluntários por grupo) foram aleatorizados para receber o placebo (carboximetilcelulose de sódio 0,5%), acetato de prednisolona 1%, cetorolaco de trometamina 0,4% e o nepafenaco 0,1%. Os colírios eram administrados 3 vezes ao dia e iniciados 48 horas antes da cirurgia.. A medida do tamanho da pupila foi realizada pelo cirurgião usando um compasso nos seguintes momentos: antes da secção da córnea e ao final da cirurgia. O desfecho primário foi avaliar a eficácia de cada medicamento em inibir a miose intraoperatoria (pupilas > 6mm, no final da cirurgia). O desfecho secundário foi obter pupilas > 6mm no inicio da cirurgia. Resultados: O numero de pacientes no grupo da prednisolona (29/35), no grupo do nepafenaco (31/35) e no grupo do cetorolaco (30/35) com diâmetro pupilar > 6 mm foi maior do que no grupo placebo em relação a manutenção da midriase intraoperatoria (19/35 - P =. 003). Não houve diferença estatística entre o grupo da prednisolona, do nepafenaco e do cetorolaco na manutenção da midriase intraoperatória (P =. 791). Não houve complicações durante a cirurgia ou efeitos adversos relacionados com o uso pré-operatório do colírio. Conclusão: O uso pré-operatório da prednisolona, do cetorolaco e do nepafenaco foi eficaz na manutenção midriase intraoperatória quando comparado com o placebo
Abstract: Introduction: Topical anti-inflammatory drugs are commonly used in the management of ocular inflammation and cystoid macular edema related to cataract surgery. It has been suggested the use of anti-inflammatory drugs before surgery, to achieve better intraoperative mydriasis. It was reported that, when mydriasis is greater than 6 mm, the incidence of posterior capsule rupture is reduced by half. The objective of the original study was to compare the effect of preoperative use of topical anti-inflammatory prednisolone acetate, ketorolac tromethamine, nepafenac and placebo, in the maintenance of intraoperative mydriasis in cataract surgery. Purpose: To compare the effects of preoperative use of topical anti-inflammatory prednisolone acetate, ketorolac tromethamine, nepafenac and placebo, on the maintenance of intraoperative mydriasis during cataract surgery. Design: Randomized clinical trial, single-center and masked. Methods: This study comprised 140 patients scheduled for cataract surgery. Patients (35 in each group) were randomized to receive placebo, prednisolone acetate, ketorolac tromethamine 0.4 % or nepafenac. These eye drops were administered three times daily for the two days prior to surgery. The pupillary diameters were measured by the surgeon using a compass prior to the corneal section and at the end of surgery. The primary outcome was the number of patients with pupil > 6 mm at the end of the surgery; the secondary outcome was the number of patients with pupil > 6 mm at the beginning of the surgery. Results: All the patients achieved pupil > 6 mm at the beginning of the surgery. The number of patients in the prednisolone (29/35), nepafenac (31/35) and ketorolac (30/35) groups with pupil > 6 mm was greater than in the placebo group in the maintenance of intraoperative mydriasis (19/35 - P =.003 - Table 2). There was no statistical difference among the prednisolone, nepafenac and ketorolac groups in the maintenance of intraoperative mydriasis (P =.791). There were no complications during surgery or related to the preoperative use of the eye drops. Conclusion: Preoperative use of ketorolac, prednisolone and nepafenac was effective in maintaining intraoperative mydriasis when compared with placebo
Mestrado
Oftalmologia
Mestre em Ciências Médicas
5
Crabtree, Helen Louise. "The Sunderland cataract study". Thesis, University of Newcastle upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430694.
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Enfield, David. "History of Cataract Extraction". The University of Arizona, 2018. http://hdl.handle.net/10150/626670.
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Löfgren, Stefan. "Cataract from ultraviolet radiation /". Stockholm : Karolinska Univ. Press, 2001. http://diss.kib.ki.se/2001/91-7349-065-2/.
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Laidlaw, David Alistair Hunter. "Second eye cataract surgery". Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322548.
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Kovalev, A., S. Vavryn, G. Gley, M. Hmyrya, O. Dudar, M. Kuibida, Y. Byts, R. Mamedzadeh, O. Linnik e A. Linnik. "VITAMIN E AND CATARACT". Thesis, Мегапринт, 2013. http://er.nau.edu.ua/handle/NAU/10099.
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Iida, Fumito. "Rupture of lens cataract : a novel hereditary recessive cataract model in the mouse". Kyoto University, 1997. http://hdl.handle.net/2433/202228.
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Figueirêdo, Eugênio Santana de 1981. "Estudo de alterações estruturais nos genes CRYAA, CRYGC e CRYGD em pacientes com catarata congênita de uma população brasileira". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/308541.
Testo completoAbstract (sommario):
Orientadores: Carlos Eduardo Leite Arieta, Mônica Barbosa de MeloTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: A catarata congênita é a principal causa de cegueira reversível na infância, com prevalência de um a cinco casos por 10.000 nascidos vivos. A forma hereditária corresponde a 50% desses casos, sendo a forma de transmissão autossômica dominante a mais comum. As alterações genéticas podem determinar mudanças no funcionamento das proteínas do cristalino, tais como cristalinas, conexinas, proteínas de transporte de membrana e proteínas de citoesqueleto. As cataratas nucleares e lamelares são as formas mais comuns entre as opacidades congênitas, e as alterações nos genes que codificam as proteínas ?A-cristalina (CRYAA), ?C-cristalina (CRYGC) e ?D-cristalina (CRYGD) têm sido relacionados com esses tipos de catarata. O presente estudo teve como objetivo determinar as alterações estruturais nos genes CRYAA, CRYGC e CRYGD em pacientes com catarata congênita bilateral, formas nuclear e lamelar, do ambulatório de catarata congênita do Hospital das Clínicas da Faculdade de Ciências Médicas da Universidade Estadual de Campinas (UNICAMP). Foram investigadas dez famílias (69 indivíduos), incluindo os casos-índice e seus parentes em primeiro grau. As regiões de codificação e as junções intron/exon foram amplificadas a partir de ácido desoxirribonucleico (DNA) genômico e submetidas à sequenciamento automático. Este estudo identificou seis polimorfismos (SNP) e uma mutação nos três genes investigados (gene CRYAA - SNP D2D, Y18Y e G137G; gene CRYGC - SNP G41G e S119S; gene CRYGD - SNP R95R e mutação Y134C), sendo três deles inéditos na literatura (G137G, G41G e Y134C). No gene CRYGD, a inédita mutação Y134C mostrou-se potencialmente deletéria para o funcionamento da proteína ?D-cristalina
Abstract: Congenital cataract is the leading cause of reversible blindness in childhood, with a prevalence of one to five cases per 10,000 live births. The hereditary form corresponds to 50% of these cases. The most common mode of inheritance is autosomal dominant with high penetrance. Genetic abnormalities determine changes in lens proteins, such as crystallins, connexins, membrane transport proteins and cytoskeletal proteins. The nuclear and lamellar cataracts are the most common among congenital opacities. Abnormalities in ?A-crystallin (CRYAA), ?C-crystallin (CRYGC) and ?D-crystallin (CRYGD) genes have been associated with these phenotypes. The present study aimed to determine the structural alterations in CRYAA, CRYGC and CRYGD genes in patients with bilateral congenital cataract, nuclear and lamellar forms, evaluated at Hospital das Clínicas, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Ambulatório de Catarata Congênita. We investigated ten families (69 individuals), including the probands and their first-degree relatives. Coding regions and intron/exon boundaries were amplified from genomic deoxyribonucleic acid (DNA) and directly sequenced. Six single-nucleotide polymorphisms (SNP) and one missense mutation were identified (CRYAA gene - SNP D2D, Y18Y and G137G; CRYGC gene - SNP G41G and S119S; CRYGD gene - SNP R95R and mutation Y134C), three of them unpublished (G137G, G41G and Y134C). In the CRYGD gene, the novel mutation Y134C proved to be potentially damaging for functioning of the ?D-crystallin protein
Doutorado
Oftalmologia
Doutor em Ciências Médicas
12
Simpson, Gregory L. W. "A mechanism for ascorbate induced cataract in human lens". free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036856.
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Huffman, Ryan Issac. "Cataract Formation After Retinal Procedures". Yale University, 2007. http://ymtdl.med.yale.edu/theses/available/etd-06282006-095623/.
Testo completoAbstract (sommario):
The purpose of this project is to study the risk of cataract development in patients who had undergone pars plana vitrectomy, scleral buckle, or both. A retrospective study was performed of phakic patients who underwent pars plana vitrectomy, scleral buckle, or both at Yale University Eye Center from 1998 to 2005. Mild postoperative cataract, defined as a change in severity of 1+, developed in 32 of 53 (60%) eyes following vitrectomy, 2 of 19 (11%) post scleral buckle, and 14 of 16 (88%) after both. Moderate postoperative cataract, defined as a change in severity of 2+, developed in 14 of 53 (26%) eyes post vitrectomy, 1 of 19 (5%) post scleral buckle, and 11 of 16 (69%) after both procedures. In eyes that underwent vitrectomy, a lens change of at least 2+ occurred in 8% at 3 months, 15% at 6 months, 21% at 12 months, and 26% at 36 months. In eyes status post scleral buckle surgery, one eye (5%) experienced a 2+ change at 36 months. In eyes that underwent both vitrectomy and scleral buckle, a lens change of at least 2+ occurred in 44% at 3 months, 50% at 6 months, 63% at 12 months, and 69% at 36 months. Cataract extraction surgery was performed in 15% of eyes post vitrectomy, 0% post scleral buckling, and 50% after both. The most common type of cataract to develop was nuclear sclerotic, which accounted for 61% of cataracts after vitrectomy, 50% after scleral buckling, and 50% after combined vitrectomy and scleral buckling. Scleral buckling surgery is associated with a low risk of cataract formation. Pars plana vitrectomy and combined vitrectomy and buckle have a higher risk of cataract development.
14
Muir, Matthew Stewart. "Proteomics of the ovine cataract". Diss., Lincoln University, 2008. http://hdl.handle.net/10182/792.
Testo completoAbstract (sommario):
The lens of the eye needs to be completely transparent in order to allow all light entering the eye to reach the retina. This transparency is maintained by the highly ordered structure of the lens proteins the crystallins. Any disruption to the lens proteins can cause an opacity to develop which is known as cataract. During cortical cataract formation there is increased truncation of the lens crystallins. It is believed that overactivation of calcium-dependent cysteine proteases, the calpains, is responsible for the increased proteolysis of the crystallins seen during cataractogenesis. Within the ovine lens there are three calpains, calpain 1, 2 and the lens specific calpain Lp82. The aim of this thesis was to determine the changes in the lens proteins during ageing and cataractogenesis, and to establish the role of the calpains in these processes. Calpain 1 and 2 were purified from ovine lung and Lp82 was purified from lamb lenses using chromatography. Activity and presence of the calpains was determined by using the BODIPY-FL casein assay, gel electrophoresis, Western blot and casein zymography. Changes in the lens proteins, specifically the crystallins, were visualised using two-dimensional electrophoresis (2DE). Lenses from fetal, 6 month old and 8 year old sheep were collected, as well as stage 0, 1, 3 and 6 cataractous ovine lenses. The proteins from the lenses were separated into the water soluble and urea soluble fractions and analysed by 2DE. Mass spectrometry was used to determine the masses and therefore modifications of the crystallins. Finally, the individual crystallins were separated using gel filtration chromatography and incubated with the purified calpains in the presence of calcium. The extent of the proteolysis was visualised using 2DE and truncation sites determined by mass spectrometry. Purification of the calpains resulted in samples that were specific for each calpain and could be used in further experiments. 2DE analysis showed that there were changes to the crystallins during maturation of the lens. The α-crystallins become increasingly phosphorylated as the lens ages and a small amount becomes truncated. The β-crystallins were also modified during ageing by truncation and deamidation. When crystallins from cataractous lenses were compared using 2DE there were changes to both the α- and β-crystallins. The α-crystallins were found to be extensively truncated at their C-terminal tail. Four of the seven β-crystallins, βB1, βB3, βB2 and βA3, showed increased truncation of their N-terminal extensions during cataract formation. All three calpains truncated αA and αB-crystallin at their C-terminal ends after incubation. Calpain 2 and Lp82 each produced unique αA-crystallin truncations. All three calpains truncated βB1 and βA3 and calpain 2 also truncated βB3. When the truncations from the calpain incubations were compared to those seen during cataract formation, many of the truncations were found to be similar. Both the unique truncations from calpain 2 and Lp82 were found in cataractous lenses, with the Lp82 more obvious in the 2DE. The β-crystallin truncations found after incubation with the calpains were similar to those found during cataractogenesis. In conclusion this study documents the changes to the ovine lens during maturation and cataractogenesis and indicates a role for the calpain family in the increased proteolysis observed in the ovine cataract.
15
Blakytny, Robert. "Experimental cataract and its prevention". Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333181.
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Riley, M. Louise. "Alcohol, aldehydes, ageing and cataract". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260233.
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Jiang, Zhirong, e 蔣志戎. "Cataract induced by osmotic stress". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31241876.
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Ndaule, Eric. "Cataract surgical services in Madagascar". Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29835.
Testo completoAbstract (sommario):
Objective: The main purpose of this study was to evaluate cataract surgical services in Madagascar to help guide the national eye health program. Methods: A retrospective study that used cataract surgical data collected between January 1st and December 31st, 2012 in 8 regional capitals (districts) of Madagascar. 1072 cataract operated eyes from 8 regional capitals supported by Kilimanjaro Centre for Community Ophthalmology (KCCO) satellite centers were analysed. Results: The study findings demonstrated a borderline post-operative visual acuity outcome after 24 hours but showed visual improvements 4 weeks after follow up. Males were more likely to have cataract surgeries compared to females. The cataract surgery rate (CSR) was 1467 in 8 regional capitals of Madagascar. Conclusion: This study demonstrated unequal distribution of cataract surgical services in Madagascar. Therefore, the findings of this study could be used to advocate for equitable provision of cataract surgery across all regions in Madagascar.
19
Giesecke, Tonia. "Ultrasonic capsulotomy in cataract surgery". Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/17541.
Testo completoAbstract (sommario):
Bibliography: pages 65-69.The human lens has two functions to fulfil. It has to transmit light and it has to change its shape according to the requirements of the accommodative process. These functions are determined respectively by the optical and mechanical properties of the lens. It is well documented that cataracts contribute to the gradual changes of the lens matrix properties. The fact is that loss of transparency due to cataract is a universal phenomenon occurring in 70% of the population over 70 years of age and that the only effective treatment for cataracts is its operative removal. In cataract surgery, anterior capsulotomy is a highly defined and crucial procedure. It involves creating a circular opening in the lens by incising the anterior surface of the lens capsule. This gives access to the lens cortex which is then extracted and replaced with a permanent plastic lens. The most popular capsulotomy technique involves tearing the capsule in a circular fashion using forceps. However, there are many potential problems to this technique such as: it is difficult to master, it takes a long time to perform and above all, it runs the risk of creating tears on the periphery of the opening. Since the capsule is retained post-operatively and acts as a support and centralisation of the artificial lens, it is necessary that the integrity of the capsule remain intact. Since anterior capsulotomy is an unpredictable procedure in cataract surgery, there is a definite need for a surgical device that can perform a reliable incision on the capsule. Using ultrasound to perform a capsulotomy is an innovative technique and its application has to be thoroughly investigated. The investigation includes a numerical and experimental analysis of the lens capsule. The numerical analysis shows that the lens capsule reaches states of resonance at frequencies above 80 kHz. It is at resonance that the capsule oscillations are increased and the cellular bonds are strained and broken. Attempts were made to perforate the human lens capsule using experimental piezoelectric transducer systems operating at resonance frequencies of 81.6, 106 and 187 kHz. Although each ultrasonic system was able to denature the lens cortex, a perforation of the lens capsule was only achieved at a frequency of 81.6 kHz. However, the perforation was irregular and exhibited several tears. This result is not acceptable as one of the main design requirements is to produce a capsulotomy that has a smooth and continuous margin. The amplitudes for the higher frequencies were inadequate to strain and break the capsule, even when the crystals were driven at their maximum voltage of 400 Volts. The present investigation proves that it is highly unlikely that an ultrasonic tool can be designed within a safe margin of frequencies and voltages. As long as no other alternative method is devised, surgeons will have to contend with the occasional complication of radial tears that occur during anterior capsulotomy using current anterior capsulotomy techniques.
20
Olofsson, Eva. "Superoxide dismutase 1 and cataract". Doctoral thesis, Umeå : Umeå universitet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-21032.
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Jiang, Zhirong. "Cataract induced by osmotic stress /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23339603.
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Painter, Geoffrey Thomas. "Corneal Protection in Cataract Surgery". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21214.
Testo completoAbstract (sommario):
Protection of the corneal endothelium is one of the most important aspects of cataract surgery. This thesis describes two studies that examine new products and techniques to protect the cornea in cataract surgery. The first study examines the corneal protective effect of a new viscoelastic, DisCoVisc, compared to two established products in a randomised control trial of 180 patients. While no objective difference in corneal protection could be found between DisCoVisc and the other two viscoelastics, DisCoVisc compared more favourably in subjective surgical behaviour when compared to Healon although no difference could be found when compared to Amvisc Plus. Complications during surgery have the potential to adversely affect the corneal endothelium. The second study is a retrospective analysis of 1589 cases of Femtosecond Laser Assisted Cataract Surgery (FLACS) using the LenSx femtosecond laser with the SoftFit patient interface. It found the rate of capsular complications using the LenSx femtosecond laser with the SoftFit patient interface was notably lower than published rates of capsular complications with manual phacoemulsification. It compares favourably with earlier studies using the LenSx platform as well as earlier studies using other femtosecond laser platforms. This study’s result is in disagreement with a meta-analysis published in 2016 which found a higher capsular complication rate with FLACS and is more in keeping with recent published studies of the safety of FLACS using the LenSx platform.
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Painter, Geoffrey Thomas. "Corneal Protection in Cataract Surgery". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21389.
Testo completoAbstract (sommario):
Protection of the corneal endothelium is one of the most important aspects of cataract surgery. This thesis describes two studies that examine new products and techniques to protect the cornea in cataract surgery. The first study examines the corneal protective effect of a new viscoelastic, DisCoVisc, compared to two established products in a randomised control trial of 180 patients. While no objective difference in corneal protection could be found between DisCoVisc and the other two viscoelastics, DisCoVisc compared more favourably in subjective surgical behaviour when compared to Healon although no difference could be found when compared to Amvisc Plus. Complications during surgery have the potential to adversely affect the corneal endothelium. The second study is a retrospective analysis of 1589 cases of Femtosecond Laser Assisted Cataract Surgery (FLACS) using the LenSx femtosecond laser with the SoftFit patient interface. It found the rate of capsular complications using the LenSx femtosecond laser with the SoftFit patient interface was notably lower than published rates of capsular complications with manual phacoemulsification. It compares favourably with earlier studies using the LenSx platform as well as earlier studies using other femtosecond laser platforms. This study’s result is in disagreement with a meta-analysis published in 2016 which found a higher capsular complication rate with FLACS and is more in keeping with recent published studies of the safety of FLACS using the LenSx platform.
24
Dell, Kevin David. "Antioxidant Intervention With manganese(Iii)-Salophen in the Selenite Cataract Model: Implications for Cataract Disease". Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/40498.
Testo completoAbstract (sommario):
Cataract disease affects millions of people worldwide. It is characterized by the accumulation of light-scattering bodies within the lens that reduce visual acuity. Cataracts are effectively treated surgically, but at great expense, costing Medicare $3.4 billion in 1997. Development of an alternative therapy for this disease would provide medical and economic benefits.
We have investigated a novel antioxidant, the superoxide scavenger Mn(III)-salophen, as a therapeutic agent in the selenite cataract model. Mn(III)-salophen has been shown to protect E. coli colonies against oxidative stress but was untested in a eukaryotic system. A total dose of 300 mmol/kg, given IP in four equal 75 mmol/kg doses spaced four hours apart, protects 75% of neonatal rats from nuclear cataract development five days after selenite injection.
Selenite is toxic through its reaction with the endogenous antioxidant glutathione (GSH). The reduction of selenite to selenide through an intermediate, selenodiglutathione (GSSeSG) leads to generation of superoxide radical, one of several toxic oxygen species that can damage the lens. Mn(III)-salophen causes an in vitro preservation of the lifetime of GSSeSG by interrupting the reduction of selenite. We have established that the reduction of GSSeSG to selenide does not use GSH as a reducing agent, but rather depends upon electrons generated in the earlier reduction of selenite to selenodiglutathione. These electrons can be intercepted by known one-electron scavengers, arresting the metabolism of GSSeSG.
Extensive proteolysis of lens crystallins and loss of calcium homeostasis occur in cataractous lenses from a rat treated with sodium selenite. The visual protection with Mn(III)-salophen is accompanied by a partial loss of the calcium homeostasis, a net increase in sodium, and calpain-mediated proteolysis of à -crystallins similar to lenses from animals treated with selenite alone. Although preservation of alpha-crystallins may contribute to the greater transparency in the protected lens, generalized à -crystallin proteolysis is insufficient for cataract formation.
From these experiments we propose that Mn(III)-salophen minimizes the oxidative stress imposed upon the cell by interfering with the metabolism of selenodiglutathione. This allows the cell to compensate for the loss of cation homeostasis and prevents aggregation of proteolyzed crystallins into cataracts.Ph. D.
25
Lundvall, Anna. "Outcome after surgery of congenital cataract /". Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-197-7/.
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Zhu, Huan. "An investigation of a mechanism on cataract formation and the study of IGF effect on lens epithelial cells". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/26307.
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Petchey, M. "Lens carbohydrate metabolism and cataract chemotherapy". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371562.
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Dowler, George Frank. "Cataract surgery in patients with diabetes". Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395831.
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Wang, Zaiqi. "Lens calcium homeostasis and selenite cataract". Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042006-164509/.
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Al, Hajj Hassan. "Video analysis for augmented cataract surgery". Thesis, Brest, 2018. http://www.theses.fr/2018BRES0041/document.
Testo completoAbstract (sommario):
L’ère numérique change de plus en plus le monde en raison de la quantité de données récoltées chaque jour. Le domaine médical est fortement affecté par cette explosion, car l’exploitation de ces données est un véritable atout pour l’aide à la pratique médicale. Dans cette thèse, nous proposons d’utiliser les vidéos chirurgicales dans le but de créer un système de chirurgie assistée par ordinateur. Nous nous intéressons principalement à reconnaître les gestes chirurgicaux à chaque instant afin de fournir aux chirurgiens des recommandations et des informations pertinentes. Pour ce faire, l’objectif principal de cette thèse est de reconnaître les outils chirurgicaux dans les vidéos de chirurgie de la cataracte. Dans le flux vidéo du microscope, ces outils sont partiellement visibles et certains se ressemblent beaucoup. Pour relever ces défis, nous proposons d'ajouter une caméra supplémentaire filmant la table opératoire. Notre objectif est donc de détecter la présence des outils dans les deux types de flux vidéo : les vidéos du microscope et les vidéos de la table opératoire. Le premier enregistre l'oeil du patient et le second enregistre les activités de la table opératoire. Deux tâches sont proposées pour détecter les outils dans les vidéos de la table : la détection des changements et la détection de présence d'outil. Dans un premier temps, nous proposons un système similaire pour ces deux tâches. Il est basé sur l’extraction des caractéristiques visuelles avec des méthodes de classification classique. Il fournit des résultats satisfaisants pour la détection de changement, cependant, il fonctionne insuffisamment bien pour la tâche de détection de présence des outils sur la table. Dans un second temps, afin de résoudre le problème du choix des caractéristiques, nous utilisons des architectures d’apprentissage profond pour la détection d'outils chirurgicaux sur les deux types de vidéo. Pour surmonter les défis rencontrés dans les vidéos de la table, nous proposons de générer des vidéos artificielles imitant la scène de la table opératoire et d’utiliser un réseau de neurones à convolutions (CNN) à base de patch. Enfin, nous exploitons l'information temporelle en utilisant un réseau de neurones récurrent analysant les résultats de CNNs. Contrairement à notre hypothèse, les expérimentations montrent des résultats insuffisants pour la détection de présence des outils sur la table, mais de très bons résultats dans les vidéos du microscope. Nous obtenons des résultats encore meilleurs dans les vidéos du microscope après avoir fusionné l’information issue de la détection des changements sur la table et la présence des outils dans l’oeilThe digital era is increasingly changing the world due to the sheer volume of data produced every day. The medical domain is highly affected by this revolution, because analysing this data can be a source of education/support for the clinicians. In this thesis, we propose to reuse the surgery videos recorded in the operating rooms for computer-assisted surgery system. We are chiefly interested in recognizing the surgical gesture being performed at each instant in order to provide relevant information. To achieve this goal, this thesis addresses the surgical tool recognition problem, with applications in cataract surgery. The main objective of this thesis is to address the surgical tool recognition problem in cataract surgery videos.In the surgical field, those tools are partially visible in videos and highly similar to one another. To address the visual challenges in the cataract surgical field, we propose to add an additional camera filming the surgical tray. Our goal is to detect the tool presence in the two complementary types of videos: tool-tissue interaction and surgical tray videos. The former records the patient's eye and the latter records the surgical tray activities.Two tasks are proposed to perform the task on the surgical tray videos: tools change detection and tool presence detection.First, we establish a similar pipeline for both tasks. It is based on standard classification methods on top of visual learning features. It yields satisfactory results for the tools change task, howev-lateer, it badly performs the surgical tool presence task on the tray. Second, we design deep learning architectures for the surgical tool detection on both video types in order to address the difficulties in manually designing the visual features.To alleviate the inherent challenges on the surgical tray videos, we propose to generate simulated surgical tray scenes along with a patch-based convolutional neural network (CNN).Ultimately, we study the temporal information using RNN processing the CNN results. Contrary to our primary hypothesis, the experimental results show deficient results for surgical tool presence on the tray but very good results on the tool-tissue interaction videos. We achieve even better results in the surgical field after fusing the tool change information coming from the tray and tool presence signals on the tool-tissue interaction videos
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Chiurciu, João Leandro Vera [UNESP]. "Análise comparativa de dois viscoelásticos dispersivos na facoemulsificação em cães portadores de catarata". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/101183.
Testo completoAbstract (sommario):
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chiurciu_jlv_dr_botfmvz.pdf: 349241 bytes, checksum: bd5d442bec2c4a00b188c9600c29d72f (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Com o trabalho, teve-se por objetivo analisar individual e comparativamente o desempenho de dois viscoelásticos, hialuronato de sódio 3% associado ao sulfato de condroitina 4% e hidroxipropilmetilcelulose 2%, frente à facoemulsificação em cães portadores de catarata madura, por meio da avaliação das alterações clínicas e variações das células endoteliais, espessura corneana e pressão intra-ocular (PIO). Foram utilizados 20 cães distribuídos em dois grupos, cada qual utilizando um dos viscoelásticos. A técnica cirúrgica adotada a foi facoemulsificação bimanual. As avaliações clínicas e tonométricas foram efetuadas antes e após o ato cirúrgico , em 1, 7, 14, 21, 28 e 60 dias de pós-operatório e a microscopia especular, antes e após 7, 28 e 60 dias. Foi efetuada a correlação entre tempo de ultra-som utilizado e as variáveis estudadas, bem como das variáveis entre sí. Utilizando-se hidroxipropilmetilcelulose 2%, ocorreu opacidade corneana, formação de fibrina e hiperemia conjuntival mais freqüentemente e de maior intensidade no período inicial. Não houve diferença estatística entre os grupos na variação da PIO, com exceção da medida feita aos 14 dias, quando foi significativamente maior com o uso de hialuronato de sódio 3% e sulfato de condroitina 4%. Não houve diferença estatística entre os grupos nos parâmetros relacionados ao endotélio. Correlação de concordância significativa foi observada somente entre densidade e área celular endotelial. O uso de hialuronato de sódio 3% e sulfato de condroitina 4% é vantajoso nos casos de densidade celular endotelial próxima ao limite inferior de normalidade.
The study aimed to assess the clinical changes and variations of the endothelial cells, corneal thickness and intra-ocular pressure (IOP) front to the facoemulsificação on dogs carriers of cataract, using viscoelastic substances the base of sodium hyaluronate 3% and sodium chondroitin sulfate 4% and comparing it with hidroxipropilmetilcelulose 2%. Twenty dogs were used distributed in two equal groups, each using one of viscoelástic materials. The surgical technique used was phaco bimanual. The clinical and tonometric evaluations were made before and after 1, 7, 14, 21, 28 and 60 days of surgery and specular microscopy before and after 7, 28 and 60 days. Correlation between time of used ultrasound and the studied variable, as well as of the variables among itself was effected. Hidroxipropilmetilcelulose 2% developed more incidence frequent and of bigger intensity in the corneal opacity, formation of fibrin and conjunctival hyperemia in the initial period. There was no statistical difference between the groups in the variation in IOP, except to 14 day, which was significantly higher with the use of sodium hyaluronate 3% and chondroitin sulfate 4%. There was no statistical difference between the groups in the parameters related to the endothelium, with slight decrease in endothelial cell density and increase of cell area with the use of hydroxypropyl 2%. Significant correlation was only observed between density and endothelial cellular area. The use of sodium hyaluronate 3% and chondroitin sulfate 4% is advantageous in cases of endothelial cell density near to the lower limit of normality.
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Eyherabide, Ana Rodrigues. "Padronização do eletrorretinograma de campo total em cães da raça Yorkshire Terrier". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-03102016-100114/.
Testo completoAbstract (sommario):
O eletrorretinograma de campo total consiste no registro da resposta elétrica difusa gerada pelas células da retina, e é considerado, nos cães, um exame essencial, principalmente nos casos de encaminhamento de cirurgia de catarata e em doenças que afetam a função retiniana. Todavia, diversos fatores podem influenciar nos valores de amplitude e tempo de culminação das respostas obtidas no exame, como idade do animal, raça, presença de catarata e seu estágio de desenvolvimento e uso da anestesia ou sedação. O objetivo desse estudo foi avaliar a interferência da idade e do estágio de desenvolvimento da catarata, além de padronizar valores da resposta dos eletrorretinogramas, nos cães da raça Yorkshire Terrier, com uso de sedação. Foram selecionadas 84 fichas e 157 olhos de exames realizados no período de 2006 a 2013. Utilizou-se aparelho de eletrorretinograma de campo total BMP-200 e eletrodo ativo corneal ERG-jet. Amplitude de pico a pico e tempo de culminação de resposta de bastonetes, máxima e cones foram obtidas. Os animais foram separados de acordo com as faixas etárias:1 a 5 anos de idade, 6 a 10 anos de idade e 11 a 15 anos de idade. Adicionalmente, os olhos selecionados foram divididos pelo estágio de desenvolvimento da catarata apresentada: incipiente, imatura, madura e hipermadura. Testes ANOVA de duas vias foram realizados para determinar possível diferença entre os grupos de tipos de catarata e entre as faixas etárias. Os valores padrão de cada grupo foi descrito. Houve diferença na amplitude da resposta de bastonetes, máxima e cones entre todas as faixas etárias, além de diferença no tempo de culminação da resposta máxima entre as faixas etárias. O aumento da idade do animal mostrou-se como o fator mais influente nos valores de amplitude de bastonetes, máxima e cones. O tempo de culminação, no entanto, mostrou-se mais estável. Os diferentes estágios de desenvolvimento de catarata apresentaram pouca interferência na resposta final do eletrorretinograma. Conclui-se que a idade é o principal fator de interferência do eletrorretinograma de campo total nos cães, nos valores de amplitude pico a pico, nas respostas de bastonetes, máxima e cones. A presença de catarata e seu estágio de desenvolvimento não foram significativosFull field electroretinogram is the record of a diffuse electrical response generated by the cells in the retina and is considered, in dogs, fundamental in cataract cases prior to surgery and retinal function affecting diseases. There are several aspects, however, that may influence amplitude and implicit time values of the exam, such as age, breed, cataract existence and stage of cataract development and anesthesia or sedation protocol. The aim of this study was to assess age and stage of cataract development interference and, additionally, standardize electroretinogram values in Yorkshire Terrier dogs using sedation. 84 records and 157 eyes were selected from 2006 to 2013 period. The BMP-200 full field electroretinogram system was used along with corneal active ERG-Jet contact lens electrode. Amplitude and implicit time values of rods, mixed rod-cone and cones were obtained. All animals were separated according the following age group: 1 to 5 years old, 6 to 10 years old and 11 to 15 years old. Additionally, the selected eyes were separated by cataract development stage, such as: incipient, immature, mature and hypermature cataract. Two-way ANOVA tests were performed to determine possible difference between cataract stage groups and age groups. Standardize values of each group was reported. There was difference in amplitude values response of rod, mixed rod-cones and cones amplitude in all age groups, in addition to difference in implicit time values of mixed rod-cones in all age groups. Animal age progression was found as the most influent factor in rod, mixed rod-cones and cones amplitude values. Implicit time values, however, exhibit a more stable response values. Cataract stage development was not substantial in influence amplitude values of rod, mixed rodcones and cone final electroretinogram responses. This study has shown that age is the main factor of full field electroretinogram interference in amplitude values response of rod, mixed rod-cones and cones in dogs. The presence of cataract and the development stage were not relevant
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Gordo, Inês Neto Afonso de Serrano. "Complicações da cirurgia de cataratas por facoemulsificação em cães". Master's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2012. http://hdl.handle.net/10400.5/4936.
Testo completoAbstract (sommario):
Dissertação de Mestrado Integrado em Medicina VeterináriaAs cataratas são um dos diagnósticos mais frequentes em oftalmologia veterinária, constituindo a principal causa de cegueira em canídeos. A abordagem cirúrgica é a única resolução eficaz, sendo a facoemulsificação a técnica de eleição. O presente estudo teve por objectivo a análise das possíveis complicações decorrentes da correcção cirúrgica de cataratas em canídeos pela técnica de facoemulsificação bimanual (coaxial). A amostra compreendeu 21 bulbos oculares de 13 cães submetidos a cirurgia de facoemulsificação no Hospital Escolar da Faculdade de Medicina Veterinária, entre Maio de 2011 e Maio de 2012. Todos os animais foram sujeitos a rigorosos critérios de selecção que incluíram a realização prévia de análises sanguíneas, electrorretinografia e ecografia ocular. Todos os animais foram submetidos a cirurgia de cataratas pela técnica de facoemulsificação bimanual. Em 85,7% dos casos procedeu-se ao implante de LIO. Os animais foram acompanhados em consultas de seguimento periódicas para observação e registo de complicações. Após a cirurgia, todos os animais recuperaram a visão. A taxa de complicações intra-operatórias foi de 47,6%. A complicação intra-cirúrgica mais frequente foi a ruptura da cápsula posterior (19%) que, apesar de não comprometer a capacidade visual do olho, inviabilizou por vezes a implantação da LIO. A taxa de complicações no pós-operatóro imediato foi de 95,2%. Este valor tão elevado deve-se ao desenvolvimento de uveíte na quase totalidade dos pacientes, o que é expectável após uma cirurgia intra-ocular. A taxa de complicações no pós-operatório a médio/longo prazo foi de 76,2%. A presença de opacidades nas cápsulas anterior (33,3%) e posterior (55,6%) foi a complicação pós-cirúrgica mais prevalente. Contudo, estas opacidades não inviabilizaram completamente a visão dos pacientes. No final deste estudo, 18 dos olhos operados estavam visuais, o que corresponde a 86% dos casos. A correcção cirúrgica de cataratas por facoemulsificação é uma cirurgia tecnicamente exigente e que possui uma taxa de complicações elevada em canídeos. Uma selecção criteriosa dos pacientes e uma boa técnica cirúrgica são factores que condicionam o sucesso da cirurgia.
ABSTRACT - Complications of cataract phacoemulsification surgery in dogs - Cataract is one of the most frequent diagnoses in veterinary ophthalmology and the leading cause of blindness in dogs. The only effective mean of treatment is surgery and phacoemulsification is the technique of choice. The purpose of the study reported here was to determine common complications after bimanual phacoemulsification surgery in dogs. Medical records of 13 dogs (21 eyes) that underwent phacoemulsification as treatment for cataract from May 2011 through May 2012 at the Teaching Hospital of the Faculty of Veterinary Medicine were reviewed. A complete pre-surgical evaluation was performed in each dog, which included CBC and biochemical profile, an electroretinogram and ocular ultrasound. All dogs had bimanual phacoemulsification surgery. Intraocular lens was placed in 85,7% of the cases. Complications noted intra- and postoperatively and visual status were recorded during periodic follow up appointments. All the ocular globes regained vision at the end of surgery. The rate of intraoperative complications was 47,6%. The most common intraoperative complication was posterior capsule disruption (19%) which sometimes precluded IOL placement. Short term postoperative complications were noted in 95,2% of the cases, mostly due to uveitis. Long term complications occurred in 76,2% of the eyes. Anterior (33,3%) and posterior (55,6%) capsule opacities were the most common postoperative complications seen in eyes though vision was still present. The majority of eyes were functionally visual (18 eyes, 86%) at the end of the study. Phacoemulsification is a very demanding surgical technique with a high prevalence of complications in dogs. Criterious patient selection and a flawless surgical technique are crucial for improving surgical outcome.
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Bartling, Karsten. "Apoferritin Crystallization in relation to Eye Cataract". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14111.
Testo completoAbstract (sommario):
Protein crystallization is significant in both biotechnology and biomedical applications. In biotechnology, crystallization is essential for determining the structure of both native and synthesized therapeutically important proteins. It can also be used as a final purification step and as a stable form for protein storage. With regard to biomedical systems, protein crystallization appears to be involved in the development and manifestation of certain human diseases. In particular, there exists evidence that L-rich ferritin crystals are involved in Hereditary Hyperferritinemia Cataract Syndrome (HHCS).
In the current research a microbatch crystallization apparatus has been introduced that enables (1) multiple batch crystallization experiments at various temperatures and solution conditions in parallel and (2) quantitative monitoring of crystal growth without disturbing the progress of an experiment for observation. The primary application of the apparatus is, but not limited to, screening of protein crystallization conditions, although the system can also be used for other macromolecular and small-molecule crystallization experiments.
Multiwell microbatch experiments demonstrated the dependence of apoferritin crystal growth kinetics and final crystal size on temperature and cadmium concentration. Although the solubility of apoferritin might be independent of temperature, the results of this study show that the crystal growth kinetics are affected by temperature, profoundly under some conditions.
For apoferritin under near physiological conditions the solution thermodynamics in the form of the second virial coefficient have proofed to be a valuable predictor for the crystallization outcome. Furthermore, the significance of the elevated level of some divalent cations in cataractous lenses has been studied both in dilute solutions and under crystallization conditions and cadmium seems to be sole menace in apoferritin condensation.
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Meyer, Linda Maren. "Cataract from ultraviolet radiation in the mouse /". Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-583-6/.
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Kugelberg, Maria. "Prevention of complications in pediatric cataract surgery /". Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-111-3/.
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Qian, Wen. "Quantitative cataract measurement with the Scheimpflug technique /". Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3930-6/.
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Kronschläger, Martin. "Prevention of Experimental Cataract Induced by UVR". Doctoral thesis, Uppsala universitet, Oftalmiatrik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-232955.
Testo completoAbstract (sommario):
Cataract is the leading cause of blindness in the world and is defined by opacification of the normally transparent lens of the eye. The major avoidable cause of cataract is ultraviolet radiation (UVR), but no current strategies have been developed to prevent the onset of cataract. Apoptosis and internal and external antioxidant systems that inhibit apoptosis have been shown to play a significant role in cataractogenesis. The main purposes of this thesis were to study the time evolution of apoptosis, to develop the concept of a protection factor (PF), and to investigate the effect of thioltransferase (Grx1) and topical caffeine in UVR cataract development. Further, to elucidate pharmacokinetics and influence on iris diameter of topical caffeine. Sprague Dawley rats were exposed to UVR and TUNEL staining of the lens sections was analysed. Grx1+/+ and Grx1-/- mice were exposed to 5 sub-doses of UVR. Based on the difference of light scattering between Grx1+/+ and Grx1-/- mice, the concept of the PF was developed. Topical caffeine and a placebo were applied to the eyes of separate groups of Sprague Dawley rats that were exposed to sub-doses of UVR and protective effect was evaluated. Penetration of topical caffeine in Sprague Dawley rats to lens and blood was analysed by high performance liquid chromatography. Pupil diameter was measured in groups of unilaterally and bilaterally caffeine-treated ketamine/xylazine anesthetized Sprague Dawley rats. TUNEL-labeling peaked between 5 and 120 hours after UVR exposure. The PF of Grx1 was 1.3. Moreover, topically administered caffeine protected against UVR-induced cataract development with a PF of 1.23. Topical caffeine peaked at 30 min in the lens, increased up to 120 min in the blood and antagonized ketamine/xylazine-induced mydriasis. In conclusion, UVR induces apoptosis, which is evidenced by the peak of TUNEL-labeling at 24 hours after UVR exposure. The PF is an objective relative measure of protective properties that allows the comparison of different antioxidant systems and administered antioxidant substances. Grx1 and caffeine are protective against UVR-induced cataract. Topically administered caffeine penetrates to the lens and inhibits UVR-induced apoptosis. Additionally, a miotic effect of caffeine is described for the first time.
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Cornish, Kelly Marie. "Dietary flavonoid quercetin in relation to cataract". Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247104.
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Elliott, D. B. "Methods of assessing the progress of cataract". Thesis, University of Bradford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381029.
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Durant, Jennifer Susan. "Risk factors for cataract : retrodots and waterclefts". Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324368.
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Smith, Martin R. "Cataract, macular characteristics and assessing lens opacities". Thesis, Aston University, 2014. http://publications.aston.ac.uk/22482/.
Testo completoAbstract (sommario):
Age-related macular degeneration and cataract are very common causes of visual impairment in the elderly. Macular pigment optical density is known to be a factor affecting the risk of developing age-related macular degeneration but its behaviour due to light exposure to the retina and the effect of macular physiology on this measurement are not fully understood. Cataract is difficult to grade in a way which reflects accurately the visual status of the patient. A new technology, optical coherence tomography, which allows a cross sectional slice of the crystalline lens to be imaged has the potential to be able to provide objective measurements of cataract which could be used for grading purposes. This thesis set out to investigate the effect of cataract removal on macular pigment optical density, the relationship between macular pigment optical density and macular thickness and the relationship between cortical cataract density as measured by optical coherence tomography and other measures of cataract severity. These investigations found: 1) Macular pigment optical density in a pseudophakic eye is reduced when compared to a fellow eye with age related cataract, probably due to differences in light exposure between the eyes. 2) Lower macular pigment optical density is correlated with thinning of the entire macular area, but not with thinning of the fovea or central macula. 3) Central macular thickness decreases with age. 4) Spectral domain optical coherence tomography can be used to successfully acquire images of the anterior lens cortex which relate well to slit lamp lens sections. 5) Grading of cortical cataract with spectral domain optical coherence tomography instruments using a wavelength of 840nm is not well correlated with other established metrics of cataract severity and is therefore not useful as presented as a grading method for this type of cataract.
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Fachinelli, Rodolfo de Lima. "Estimativa da ceratometria média a partir dos dados biométricos e refração pós-operatórios de olhos de crianças submetidas à facectomia por catarata congênita e do desenvolvimento". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153418.
Testo completoAbstract (sommario):
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Objetivo: Comparar a ceratometria média aferida (KA) sob narcose em crianças submetidas à facectomia, por catarata congênita ou do desenvolvimento, com a ceratometria média obtida por cálculo teórico (KC), utilizando o poder dióptrico da lente intraocular (LIO) implantada e dados refracionais e biométricos pós-operatórios, a fim de evidenciar possíveis erros de aferição da KA devido a narcose. Métodos: Estudo retrospectivo realizado a partir da análise de dados coletados de prontuários de pacientes com catarata bilateral, congênita ou do desenvolvimento, que receberam tratamento cirúrgico no HC-FMB. Foram analisados 73 olhos de crianças que possuíam pelo menos um exame pós-operatório completo, cada momento em que determinado olho foi examinado foi considerado um elemento do conjunto amostral, totalizando 165 momentos. KC foi obtida a partir de fórmula teórica para cálculo de LIO, utilizando os dados biométricos pós-operatórios (AL e ACD), refratometria automatizada pós-operatória e poder dióptrico da LIO implantada. Foi calculada a diferença entre KA e KC (Desvio = KA – KC). Para análise estatística dos desvios encontrados e comparação entre KA e KC, foi realizado o teste de associação de Goodman e o teste não paramétrico de Kruskal-Wallis. Resultados: A média de idade no momento da cirurgia do primeiro olho foi 954,62 dias, com desvio padrão de ±794,14 dias, mediana de 953 dias, sendo a idade mínima de 44 dias e a máxima de 2659 dias. Vinte e três eram do sexo masculino (62,16%) e 14 eram do sexo feminino (37,84%). KA variou de 40,62D a 51,50D, com mediana de 45,25D, média de 45,32D e desvio padrão de ±2,37D. KC variou de 39,40D a 52,26D, com mediana de 44,49D, média de 44,54D e desvio padrão de ±2,41D. Os desvios (Desvio = KA – KC) variaram de -2,28D a 3,81D, com mediana de 0,83D, média de 0,79D e desvio padrão de ±1,18D. A relação entre KC e KA pode ser representada pela equação KA = 1,0172 Kc. Conclusão: A comparação entre KC e KA em crianças sob narcose evidenciou que há superestimação do valor aferido em relação ao calculado. A análise dos desvios encontrados mostrou tendência para maior superestimação quanto maior a KA com diferença significativa (p<0,05) nas aferições acima de 44,0D.
Purpose: To compare the mean keratometry measured (KA) in children under anesthesia to receive surgical treatment for congenital or developmental cataract with a mean keratometry obtaeined by a theoretical formula (KC), using the implanted intraocular lens (IOL) power value and postoperative refractional and biometric data, in order to check possible observational erros of KA due to general anesthesia. Methods: A retrospective study analysing records of patients with congenital or developmental bilateral cataract who underwent surgical treatment at HC-FMB. Seventy-three children’s eyes that had at least one full postoperative exam were analyzed, each time one eye was assessed was considered one element of the sample group, and the total amount was 165 elements. KC was determined by a theoretical formula for calculating IOL power using postoperative biometric data (AL e ACD), postoperative automatic refractometery and refractive power of the implanted IOL. The KA observational error value was obtained by subtracting KC from KA (Error = KA - KC). Statistical analysis of the observational erros and the comparison between KA and KC were made by Goodman’s test and Kruskal-Wallis’ non-parametric test. Results: the mean age at the moment of the first surgery was of 954,62 days, the standard deviation was ±794,14 days, the median was 953 days, the minimum age was 44 days and the maximum age was 2659 days. Twenty-three (62,16%) patients were male and 14 (37,84%) female. KA ranged from 40,62D to 51,50D, the median was 45,25D, the mean was 45,32D and the standard deviation was ±2,37D. KC ranged from 39,40D to 52,26D, the median was 44,49D, the mean was 44,54D and the standard deviation was ±2,41D. Observational errors ranged from -2,28D to 3,81D, the median was 0,83D, the mean was 0,79D and the standard deviation was ±1,18D. The rate between KC and KA can be represented by the equation KA = 1.0172 KC. Conclusion: The comparison between KC and KA in children under general anesthesia showed that there is an overestimation of the value measured when compared to the calculated one. The analysis of the observational errors showed there is a tendency to greater overestimation the higher the KA, with significant difference (p <0.05) in the measurements over 44.0D.
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Chen, Hongyuan. "Design, synthesis and testing of calpain inhibitors for the treatment of cataract". Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/1405.
Testo completoAbstract (sommario):
This thesis reports the development of potent and selective inhibitors of m-calpain for the treatment of cataract. SJA6017 has been proven to prevent lens opacity in rat and has been our lead compound. A series of Val-Leu peptidyl aldehyde inhibitors (33a-e, 33g, 33i and 35) have been designed, synthesized, and tested for therapeutic potential as cataract inhibitors. Chapter 1 is an introduction to calpain and the diseases associated with it's over activation. A review of the literature on calpain inhibition is given. Structure activity relationship (SAR) theory is presented. The techniques that have been applied in our research group to drug design include molecular modeling, synthesis, assay and animal studies which are all briefly discussed. The importance of a -strand conformation for an inhibitor to bind to calpain is discussed. Chapter 2 describes the synthesis of m-calpain inhibitors. This comprises the preparation of the Val-Leu dipeptide core 29, Val-Leu dipeptidyl alcohols 31a-g and 31i, and the synthesis of dipeptidyl aldehydes 33a-e, 33g, 33i and 35. The choice of coupling regents and conditions in the coupling reactions is investigated. Sulfur trioxide pyridine oxidation for the conversion of Val-Leu dipeptidyl alcohols to aldehydes is discussed. The molecular modeling and biological assay results are presented.
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Magwebu, Zandisiwe Emilia Z. E. "Molecular genetics: strategies to identify congenital cataract genes in captive-bred vervet monkeys". University of the Western Cape, 2013. http://hdl.handle.net/11394/4265.
Testo completoAbstract (sommario):
>Magister Scientiae - MScMolecular genetics: strategies to indentify congenital cataract genes in captive-bred Vervet monkeys Zandisiwe Emilia Magwebu MSc thesis, Department of Medical Biosciences, University of the Western Cape The present study describes molecular aspects of inherited congenital cataract in captive-bred Vervet monkeys. Congenital cataracts are lens opacities that are present at birth or soon after birth and include hereditary cataracts or cataracts caused by infectious agents. The MRC Primate Unit is housing a colony of captive-bred Vervet monkeys in which 7.5% is suffering from congenital cataract. However, the parents of the affected individuals were asymptomatic. Six families within the colony have been identified to be affected by two types of morphologies (Ysutural and total cataract). Based on the evidence provided above, it was speculated that the colony was affected with autosomal recessive cataract. The main aim of this study was to facilitate a strategy for managing breeding programs by minimizing cataract occurrences in captive-bred Vervet monkeys. Integrated combination of clinical, molecular and bioinformatic strategies were used to identify and assess reciprocal candidate susceptibility genes for cataracts. The genes that are known to be responsible for most human congenital cataract cases were prioritized. The genes include Heat shock transcription factor 4 (HSF4), Crystalline Alpha A (CRYAA), glucosaminyl (N-acetyl) transferase 2 (GCNT2) and Lens intrinsic membrane protein 2 (LIM2). Twenty two subjects were selected based on their morphology (5 carriers, 5 controls and 12 cataracts). 2ml of blood was collected for Deoxyribonucleic acid (DNA) extraction. Coding exons and flanking regions were screened by polymerase chain reaction (PCR) amplification and sequenced. The CLC DNA workbench was used for results analysis. The screening of four genes revealed 20 sequence variants which were not present in the control individuals. Sequencing of HSF4 revealed three mutations: R116R, L245>L and P421>L in exon 5, 10 and 14, respectively. The coding exons for CRYAA showed two sequence variants: S134W and K166N in exon 3. Twelve mutations were identified in exon one of all three GCNT2 transcripts (A, B and C). These mutations include: G212G, H256>H, M258>V, N275>N, V16>I, Y122>F, S15>S, S24>N, S38>S, I118>I, D194>D and Y373>Y which was found in exon three of all transcripts. There were no mutations in LIM2, however, three single nucleotide polymorphisms (SNPs) were identified in exon 2 (P66>P) and 3 (I118>T and A127>T). The above mutations were conserved when aligned with other species. The sequence variations vary among the families and those individuals with the same or different cataract phenotype. Based on these findings, it can be concluded that the four candidate genes harbour mutations that are responsible for both phenotypes. The effect of these mutations in Vervet monkeys is not yet understood, however, their impact will be further investigated. For future studies, it will be of absolute importance to screen the entire family to verify that indeed cataract formation in this colony is inherited in an autosomal recessive manner.
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Magwebu, Zandisiwe Emilia. "Molecular genetics: strategies to identify congenital cataract genes in captive-bred Vervet monkeys". Thesis, University of the Western Cape, 2012. http://hdl.handle.net/11394/4402.
Testo completoAbstract (sommario):
Magister Scientiae (Medical Bioscience) - MSc(MBS)The present study describes molecular aspects of inherited congenital cataract in captive-bred Vervet monkeys. Congenital cataracts are lens opacities that are present at birth or soon after birth and include hereditary cataracts or cataracts caused by infectious agents. The MRC Primate Unit is housing a colony of captive-bred Vervet monkeys in which 7.5% is suffering from congenital cataract. However, the parents of the affected individuals were asymptomatic. Six families within the colony have been identified to be affected by two types of morphologies (Y-sutural and total cataract). Based on the evidence provided above, it was speculated that the colony was affected with autosomal recessive cataract. The main aim of this study was to facilitate a strategy for managing breeding programs by minimizing cataract occurrences in captive-bred Vervet monkeys. Integrated combination of clinical, molecular and bioinformatic strategies were used to identify and assess reciprocal candidate susceptibility genes for cataracts. The genes that are known to be responsible for most human congenital cataract cases were prioritized. The genes include Heat shock transcription factor 4 (HSF4), Crystalline Alpha A (CRYAA), glucosaminyl (N-acetyl) transferase 2 (GCNT2) and Lens intrinsic membrane protein 2 (LIM2). Twenty two subjects were selected based on their morphology (5 carriers, 5 controls and 12 cataracts). 2ml of blood was collected for Deoxyribonucleic acid (DNA) extraction. Coding exons and flanking regions were screened by polymerase chain reaction (PCR) amplification and sequenced. The CLC DNA workbench was used for results analysis. The screening of four genes revealed 20 sequence variants which were not present in the control individuals. Sequencing of HSF4 revealed three mutations: R116R, L245>L and P421>L in exon 5, 10 and 14, respectively. The coding exons for CRYAA showed two sequence variants: S134W and K166N in exon 3. Twelve mutations were identified in exon one of all three GCNT2 transcripts (A, B and C). These mutations include: G212G, H256>H, M258>V, N275>N, V16>I, Y122>F, S15>S, S24>N, S38>S, I118>I, D194>D and Y373>Y which was found in exon three of all transcripts. There were no mutations in LIM2, however, three single nucleotide polymorphisms (SNPs) were identified in exon 2 (P66>P) and 3 (I118>T and A127>T). The above mutations were conserved when aligned with other species. The sequence variations vary among the families and those individuals with the same or different cataract phenotype. Based on these findings, it can be concluded that the four candidate genes harbour mutations that are responsible for both phenotypes. The effect of these mutations in Vervet monkeys is not yet understood, however, their impact will be further investigated. For future studies, it will be of absolute importance to screen the entire family to verify that indeed cataract formation in this colony is inherited in an autosomal recessive manner.
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Martins, Cristiane Maria Gomes. "Impacto da catarata congênita na sensibilidade ao contraste espacial de luminância em crianças". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-15032013-105656/.
Testo completoAbstract (sommario):
A opacificação do cristalino presente ao nascimento ou nos primeiros meses de vida é denominada de Catarata Congênita (CC). As primeiras semanas de vida são importantes no desenvolvimento visual, já que há diferença significativa no desempenho visual de crianças que passaram pela cirurgia até seis semanas de vida (com melhor desempenho visual) em relação às crianças que realizaram a cirurgia após seis semanas de vida. Crianças que tiveram privação visual durante a primeira infância por catarata bilateral apresentam redução da visão espacial. O objetivo deste trabalho foi verificar o impacto na Função de Sensibilidade ao Contraste (FSC) em crianças de tratamento cirúrgico de Catarata Congênita, durante a fase de desenvolvimento visual. Foram avaliados três grupos: 11 crianças do grupo controle (média idade =6,83; DP=1,38), 9 crianças do grupo CC (média idade =6,87; DP=2,03) e 15 indivíduos adultos (média idade =27,63; DP=4,16). Foi utilizado o software Metropsis para avaliação da sensibilidade ao contraste de luminância de grade senoidal nas frequências espaciais de 0,2 cpg; 0,5 cpg; 1,0 cpg; 2,0 cpg; 4,2 cpg e 8,9 cpg e luminância média de 34,4 cd/m². Houve redução em toda a curva de sensibilidade ao contraste (SC) do grupo CC quando comparado ao grupo controle e não houve relação entre o tempo de privação e a redução da SCThe opacification of the lens present at birth is called Congenital Cataract (CC). The first weeks of life are important in visual development since there is not any significant difference in visual performance of children who had surgery within six weeks of life (with better visual performance) compared with children who underwent surgery after this period. Children who have visual deprivation during infancy due to bilateral cataracts have reduced spatial vision. The aim of this study was to assess the impact on Contrast Sensitivity Function (CSF) in children with Congenital Cataract surgery during the visual development age range. We evaluated three groups: 11 control children (mean age = 6.83, SD = 1.38), 9 children in the CC group (mean age = 6.87, SD = 2.03) and 15 adults (mean age = 27.63, SD = 4.16). Metropsis software was used to evaluate sensitivity to luminance contrast of the sinusoidal grating spatial frequencies of 0.2 cpd, 0.5 cpd, 1.0 cpd, 2.0 cpd, 4.2 cpd and 8.9 cpd with an average luminance of 34.4 cd / m². There was a reduction in the contrast sensitivity function (CSF) of the CC group compared to the control group and there was no correlation between the duration of deprivation and the impairment in the SC
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Prado, Rodrigo Bueno do. "Estudo prospectivo do desenvolvimento biométrico de olhos com catarata congênita e do desenvolvimento /". Botucatu, 2014. http://hdl.handle.net/11449/113881.
Testo completoAbstract (sommario):
Orientador: Antônio Carlos Lottelli RodriguesBanca: Carlos Roberto Padovani
Banca: André Messias
Resumo: OBJETIVO. Avaliar o comprimento axial (AL), profundidade da câmara anterior (ACD) e espessura do cristalino (LT) de olhos de crianças a termo com catarata congênita e do desenvolvimento não complicada e fornecer estimativas específicas por idade. MÉTODO. Estudo retrospectivo de crianças submetidas à facectomia entre junho de 2011 e janeiro de 2014. Foram incluídas crianças com catarata não complicada sem patologias oculares e idade inferior a dez anos. Dados biométricos foram obtidos com biômetro de imersão. Procedeu-se a análise estatística dos dados e a regressão linear com o logaritmo da idade para modelar a relação do AL com a idade. RESULTADOS. Todos os olhos de 41 crianças foram incluídos na análise, com média de idade de 37,3 meses. A idade teve relação significativa com as medidas de AL (p<0,01). Eram 23 do sexo masculino (56%). Tiveram média de idade de 32,1 meses no sexo masculino e 44 meses no feminino, com baixa relação de AL segundo o sexo (p>0,05). As médias e desvio padrão de AL em olhos com catarata unilateral (n=16) e um dos olhos aleatoriamente selecionado (n=25) nos casos bilaterais foram de 20,37 mm ± 2,11 e 20,54 mm ± 1,97 respectivamente. Medidas de AL tiveram relação linear positiva com ACD e LT. Olhos com catarata unilateral tiveram AL menor que olhos sadios contralaterais. CONCLUSÃO. Medidas de AL alteram significativamente com a idade, principalmente nos 6 primeiros meses. O estudo prediz valores de AL nas diversos grupos etários, contribuindo para o cálculo do poder de lente intraoculares em crianças
Abstract: PURPOSE. To evaluate the axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) of eyes of full-term infants with congenital and development cataracts uncomplicated and provide specific estimates by age. METHOD. Retrospective study of children undergoing cataract surgery between June 2011 and January 2014. Children with uncomplicated cataract without ocular pathologies and less than ten years old were included. Biometric data were obtained with immersion biometer. Proceeded to statistical analysis and linear regression with logarithm of age to model the relationship of AL with age. RESULTS. All eyes of 41 children were included in the analysis, with a mean age of 37.3 months. Age had a significant relationship with measures of AL (p< 0.01). 23 were male (56%). Had a mean age of 32.1 months for males and 44 months in females, with low ratio of AL according to gender (p>0.05). The mean and standard deviation of AL in eyes with unilateral cataract surgery (n=16) and randomly selected one eye in bilateral cases (n=25) were 20.37 ± 2.11 mm and 20.54 mm ± 1.97 respectively. AL measures had a positive linear relationship with ACD and LT . Eyes with unilateral cataract had smaller AL than the contralateral healthy eyes. CONCLUSION. AL measures change significantly with age, especially in the first six months. The study predicts values of AL in various age groups, contributing to the calculation of intraocular lens power in children
Mestre
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Rosha, Deepinder Singh. "Chemoprophylaxis for the prevention of endophthalmitis after cataract surgery: patterns of use and economic costs". Thesis, Curtin University, 2006. http://hdl.handle.net/20.500.11937/2135.
Testo completoAbstract (sommario):
Objectives: The objectives of study were to (i) examine the regional differences in methods of performing cataract surgery across different jurisdictions in Australia and New Zealand (ii) identify risk factors for post-operative endophthalmitis and (iii) explore the implication of changes in surgical practice on the number of cases of post-operative endophthalmitis and resultant net cost to health system. Methods: Cataract surgeons across Australia and New Zealand were surveyed about their demographics, surgical techniques, use of pre- and post-operative antibiotics and antiseptics and cases of post-operative endophthalmitis. Statistical analysis was conducted to determine the regional variations in the use of methods of chemoprophylaxis and surgical practices. Multivariate Poisson regression was performed to identify factors associated with the incidence of post-operative endophthalmitis. A cost analysis was conducted to determine the impact of an increased use of chemoprophylatic treatment on the number of cases of post-operative endophthalmitis and net cost savings to the health system from its use. In addition, the results of the current survey of surgical practices of cataract surgeons was compared with those from an earlier survey conducted approximately 10 years ago. Result: The response to the survey of ophthalmologists was 82%, but after excluding ophthalmologists who did little or no cataract surgery, the study sample comprised 540 participants of the 896 who were initially sent the survey. Participating cataract surgeons reported 162,120 cataract surgeries and 92 cases of post-operative endophthalmitis, an incidence rate of 0.056%. Regional variations were found in the methods of chemoprophylaxis and surgical techniques.Chloramphenicol was the most frequently used topical antibiotic in Australia, while neomycin was used by majority of cataract surgeons in New Zealand. The only notable change found over the past decade was a sharp fall in use of subconjunctival antibiotics from 75% to 45% in the current survey. A slight increase in use of post-operative topical antibiotics was noticed. Subconjunctival injection of antibiotics was the only form of chemoprophylaxis associated with a reduction in incidence of endophthalmitis. Results from this survey indicated that cataract surgeons routinely using corneal or limbal incisions had an incidence of endophthalmitis considerably higher than those surgeons routinely using scleral wounds, whilst surgeons routinely using temporally sited wounds had almost half the incidence of endophthalmitis compared to surgeons using superior wounds. The cost implications of subconjunctival gentamycin injection for chemoprophylaxis were examined. Additional costs of subconjunctival antibiotics were subtracted from the reduced cost of treating fewer cases endophthalmitis. There would potentially be a net saving to the Australian health system of $ 110,354 if all cataract surgeons used subconjunctival chemoprophylaxis. Conclusion: Regional variation in chemoprophylaxis and surgical techniques did not entirely explain differences in post-operative endophthalmitis incidence. Subconjunctival antibiotics would only need to reduce the incidence of endophthalmitis by 15% for it to be cost-effective.
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Hamam, Abdelwahab. "A three-dimensional haptic cataract tele-surgery simulation". Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27519.
Testo completoAbstract (sommario):
Medical simulations are becoming more advanced and more reliable in training medical students and new surgeons. Especially in the context of delicate surgeries, such as cataract surgery, the medical community is shifting from traditional medical training to sophisticated virtual reality simulations. In this thesis, we present a simulation built in a three-dimensional environment that aids in training medical residents to perform cataract surgeries. The application utilizes haptic devices as a means of interaction, which enriches the application by providing a sense of touch and force-feedback to users. In addition, we discuss our modeling of the environment and the decisions undertaken in the design. We also compare this 3D application with similar applications in terms of functionality but with different user interfaces, and mention what was the eye surgeon's reaction towards each interface in the training simulation. Finally, we conclude with future modifications of the application and describe a future direction.