Overview: Optical concepts as they relate to the ophthalmologic correction of vision in corneal laser vision correction and intraocular lens design was examined. Purpose: The interaction between the excimer laser and residual corneal tissue in laser vision correction produces unwanted side effects. Understanding the origin of these artifacts can lead to better procedures. Furthermore, accommodating intraocular lenses offer a potential for eliminating presbyopia. Understanding the properties of a new accommodating intraocular lens incorporating a deformable interface may lead to advances in cataract surgery. Introduction: Corneal surface irregularities following laser refractive procedures are commonly seen. They regularly result in a patient’s decreased best corrected visual acuity and decreased contrast sensitivity. These changes are only seen in biologic tissue and the etiology has been elusive. A thermal response has been theorized and was investigated in this research. In addition, intraocular lenses using a mechanically deforming interface to change their power in order to duplicate natural accommodation have been developed. The deforming interface(s) induce optical aberrations due to irregular deformations. Design efforts have centered on minimizing these deformations. Both of the ophthalmic applications have been analyzed using finite element analysis (FEA) to understand their inherent optical properties. Methods: FEA modeling of thermal theory has been applied to verify that excimer laser induced collagen contraction creates corneal surface irregularities and central islands. A mathematical model which indicates the viability of the theory was developed. The modeling results were compared to post ablation changes in eyes utilizing an excimer (ArF 193 nm), as well as non-ablative thermal heating in eyes with a CO₂ laser. Addition modeling was performed on an Intraocular lens prototype measuring of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio. Prototype verified mathematical models were utilized to optimize optical and mechanical design parameters to maximize the image quality and minimize the required force. Results: The predictive model shows significant irregular central buckling formation and irregular folding. The amount of collagen contraction necessary to cause significant surface changes is very small (0.3%). Uniform scanning excimer laser ablation to corneal stroma produces a significant central steepening and peripheral flattening in the central 3mm diameter. Isolated thermal load from uniform CO₂ laser irradiation without ablation also produces central corneal steepening and paracentral flattening in the central 3mm diameter. The iterative mathematical modeling based upon the intraocular lens prototype yielded maximized optical and mechanical performance through varied input mechanical and optical parameters to produce a maximized visual Strehl ratio and a minimized force requirement. Conclusions: The thermal load created by laser irradiation creates a characteristic spectrum of morphologic changes on the porcine corneal stromal surface which correlates to the temperature rise and is not seen inorganic, isotropic material. The highly similar surface changes seen with both lasers are likely indicative of temperature induced transverse collagen fibril contraction and stress re-distribution. Refractive procedures which produce significant thermal load should be cognizant of these morphological changes. The optimized intraocular lens operates within the physiologic constraints of the human eye including the force available for full accommodative amplitude using the eye’s natural focusing feedback, while maintaining image quality in the space available. Optimized optical and mechanical performance parameters were delineated as those which minimize both asphericity and actuation pressure. The methodology combines a multidisciplinary basic science approach from biomechanics, optical science, and ophthalmology to optimize an intraocular lens design suitable for preliminary trials.

Mode of access: World Wide Web. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 86-97). / Electronic reproduction. / Also available by subscription via World Wide Web / xv, 97 leaves, bound ill. 29 cm

Orientador: Antônio Carlos Lottelli Rodrigues / Banca: Wallace Chamon Alves de Siqueira / Banca: Carlos Roberto Padovani / Resumo: OBJETIVO: Estabelecer, para olhos com catarata congênita e do desenvolvimento, modelos matemáticos para o cálculo da taxa de crescimento axial diário (TCA) e cálculo do comprimento axial (Axl) em qualquer idade futura, a partir da idade e do Axl medido, no momento da cirurgia. MÉTODOS: Estudo retrospectivo de crianças submetidas à facectomia com implante de LIO entre janeiro de 2011 a 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 estabeleceu-se fórmulas matemáticas para cálculo da TCA e Axl. RESULTADOS: Foram operados 54 olhos de 33 crianças sendo 19 masculinos (57,58%) e 14 femininos (42,42%). Dos 33 casos analisados, 12 eram cataratas unilaterais (36,37%) e 21 eram cataratas bilaterais (63,63%). Nos casos de catarata bilateral utilizou-se apenas os dados do olho direito de cada criança. A amostra foi dividida em 3 grupos (cataratas unilaterais e bilaterais, cataratas unilaterais, cataratas bilaterais) e para cada grupo foi estabelecido uma fórmula matemática para cálculo da TCA e Axl. CONCLUSÕES: O presente estudo propõe uma nova maneira de abordagem no cálculo da LIO, não baseada em resultados refracionais pós-operatório mas em uma taxa de crescimento diário (TCA). As equações geradas permitem estabelecer a taxa de crescimento diária em qualquer idade e principalmente a permitem "prever" Axl futuro a partir de um Axl inicial medido. Não é possível concluir pelo presente estudo que o método proposto é superior a outros métodos de estimação do crescimento ocular. Estudos comparativos entre eles serão necessários para avaliar esta precisão / Abstract: PURPOSE: Establish, for the eyes with congenital and development cataract, mathematical models to calculate the daily axial growth rate (AGR) and calculation of the axial length (Axl) in any future age, from the age and Axl measured at the time of surgery. METHODS: Retrospective study of children undergoing cataract extraction with IOL implantation between January 2011 and January 2014. We included children with uncomplicated cataract without eye diseases and the age of ten years. Biometric data were obtained with plunge biometer. We carried out the statistical analysis of data and established mathematical formulas to calculate the AGR and Axl. RESTULTS: Were operated on 54 eyes of 33 children, 19 male (57.58%) and 14 female (42.42%). Of the 33 cases analyzed, 12 were unilateral cataracts (36,37%) and 21 were bilateral cataracts (63.63%). In cases of bilateral cataracts was used only the right eye of the data of every child. The sample was divided into 3 groups (unilateral and bilateral cataracts, unilateral cataracts, bilateral cataracts) and for each group was established a mathematical formula to calculate the AGR and Axl. CONCLUSIONS: This study proposes a new way to approach the calculation of IOL, not based on postoperative refractive results but on a daily growth rate (AGR). The generated equations for establishing the daily growth rate at any age and especially to allow "predict" Axl future from a measured initial Axl. Can not complete with this study that the proposed method is superior to other methods of estimation of eye growth. Comparative studies between them will be needed to assess this accurately / Mestre

Katarakt är en grumling i ögats lins som leder till nedsatt syn. Detta tillstånd är fortfarande en av de främsta orsakerna till nedsatt syn i hela världen och kataraktoperationer är därför en av de vanligaste operationerna inom ögonkirurgi. Patienter upplever att den information de får om det kirurgiska ingreppet ofta är bristfällig. Det är komplext att ge information inför en ögonoperation. Syftet med denna integrativa litteraturstudie var att belysa faktorer som bidrar till patientnöjdhet i samband med kataraktoperationer. Datainsamling gjordes i specifika databaser som CINAHL, PubMed och SienceDirect, vilka innehåller flest tidskriftsartiklar från området medicin och omvårdnad. En analys av tio artiklar genomfördes. Litteraturstudien resulterade i tre kategorier av patientnöjdhet: Information, Hälso-och sjukvårdspersonalens bemötande och Trygghet. Många olika faktorer bidrar till patientnöjdhet. De viktigaste faktorerna är att få en individuell och patientanpassad information om kataraktoperationen, att hälso-och sjukvårdpersonalen har ett respektfullt och vänligt bemötande mot patienten samt att kunna känna trygghet. Resultatet visade också att ögonsjuksköterskan har en viktig roll när det gäller att stödja och informera patienter i samband med kataraktoperationer. Genom att förstå patienters upplevelser kan ögonsjuksköterskan hjälpa och bemöta dem på ett bättre sätt. I utbildningen till ögonsjuksköterskor bör resultatet i denna litteraturstudie kunna användas men det rekommenderas att större studier görs om patientupplevelser vid kataraktoperationer i Sverige. / A cataract is a clouding oft he lens of the eye that leads to impaired vision. This condition remains one of the main causes of vision impairment worldwide. Cataract surgery is amongthe most common eye interventions all over the world. Patients often consider that the information they receive about the surgical procedure is inadequate. It is difficult to provide information about eye surgery. The aim of this integrative literature review was to highlight factors that contribute to patient satisfaction in cataract surgery. Data collection took place in databases such as CINAHL, PubMed and SienceDirect, which mainly contain scientific articles from the field of medicine and nursing. The study includes an analysis of ten articles. The literature review resulted in three categories of patient satisfaction: Information, Healthcare professionals`response and Safety. Many different factors that contribute to patient satisfaction. The most important factors are to get individual and patient information about cataract surgery, respectful and friendly encountering by the healthcare professionals and being able to feel safe. The result revealed even that the ophthalmic nurse has an important role in supporting and informing the patient in the context of cataract surgery. Ophthalmology nurses can encounter patients in a more professional manner if they understandpatients` experiences. In the education of ophthalmology nurses, the result of this  literature study should be able to be used, but it is recommended that greater studies be done on patient experience in cataract surgery in Sweden.

Made available in DSpace on 2015-12-10T14:23:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-30. Added 1 bitstream(s) on 2015-12-10T14:30:03Z : No. of bitstreams: 1 000849018.pdf: 133262 bytes, checksum: 79e5100459efce332b6b39f84987e89f (MD5) / OBJETIVO: Estabelecer, para olhos com catarata congênita e do desenvolvimento, modelos matemáticos para o cálculo da taxa de crescimento axial diário (TCA) e cálculo do comprimento axial (Axl) em qualquer idade futura, a partir da idade e do Axl medido, no momento da cirurgia. MÉTODOS: Estudo retrospectivo de crianças submetidas à facectomia com implante de LIO entre janeiro de 2011 a 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 estabeleceu-se fórmulas matemáticas para cálculo da TCA e Axl. RESULTADOS: Foram operados 54 olhos de 33 crianças sendo 19 masculinos (57,58%) e 14 femininos (42,42%). Dos 33 casos analisados, 12 eram cataratas unilaterais (36,37%) e 21 eram cataratas bilaterais (63,63%). Nos casos de catarata bilateral utilizou-se apenas os dados do olho direito de cada criança. A amostra foi dividida em 3 grupos (cataratas unilaterais e bilaterais, cataratas unilaterais, cataratas bilaterais) e para cada grupo foi estabelecido uma fórmula matemática para cálculo da TCA e Axl. CONCLUSÕES: O presente estudo propõe uma nova maneira de abordagem no cálculo da LIO, não baseada em resultados refracionais pós-operatório mas em uma taxa de crescimento diário (TCA). As equações geradas permitem estabelecer a taxa de crescimento diária em qualquer idade e principalmente a permitem prever Axl futuro a partir de um Axl inicial medido. Não é possível concluir pelo presente estudo que o método proposto é superior a outros métodos de estimação do crescimento ocular. Estudos comparativos entre eles serão necessários para avaliar esta precisão / PURPOSE: Establish, for the eyes with congenital and development cataract, mathematical models to calculate the daily axial growth rate (AGR) and calculation of the axial length (Axl) in any future age, from the age and Axl measured at the time of surgery. METHODS: Retrospective study of children undergoing cataract extraction with IOL implantation between January 2011 and January 2014. We included children with uncomplicated cataract without eye diseases and the age of ten years. Biometric data were obtained with plunge biometer. We carried out the statistical analysis of data and established mathematical formulas to calculate the AGR and Axl. RESTULTS: Were operated on 54 eyes of 33 children, 19 male (57.58%) and 14 female (42.42%). Of the 33 cases analyzed, 12 were unilateral cataracts (36,37%) and 21 were bilateral cataracts (63.63%). In cases of bilateral cataracts was used only the right eye of the data of every child. The sample was divided into 3 groups (unilateral and bilateral cataracts, unilateral cataracts, bilateral cataracts) and for each group was established a mathematical formula to calculate the AGR and Axl. CONCLUSIONS: This study proposes a new way to approach the calculation of IOL, not based on postoperative refractive results but on a daily growth rate (AGR). The generated equations for establishing the daily growth rate at any age and especially to allow predict Axl future from a measured initial Axl. Can not complete with this study that the proposed method is superior to other methods of estimation of eye growth. Comparative studies between them will be needed to assess this accurately

Made available in DSpace on 2014-11-10T11:09:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-19Bitstream added on 2014-11-10T11:57:31Z : No. of bitstreams: 1 000789734.pdf: 694158 bytes, checksum: 375636a369a19e27c6049147bd6c8934 (MD5) / Objetivo: Avaliar a reprodutibilidade, complicações intra e pós-operatória e resultados refracionais da técnica de implante primário de LIO seguido de capsulotomia posterior e vitrectomia anterior via pars plana/plicata para tratamento da catarata congênita e do desenvolvimento. Pacientes e métodos: Crianças portadoras de catarata congênita e do desenvolvimento, uni ou bilateral com indicação de tratamento cirúrgico com idades de zero a 12 anos. Foram excluídos olhos com diâmetro corneano horizontal menor que 10 mm ou outras alterações. Resultados: 50 olhos operados de 35 crianças sendo 18 masculinos (51,42%) e 17 femininos (48,58%). A idade variou de 2 meses a 12 anos. 20 olhos eram de crianças com menos de 1 ano de idade. 19 casos (76%) apresentaram catarata bilateral e 12 casos unilaterais (24%). Nenhuma complicação intra-operatória foi observada. Em relação a complicações pós-operatórias observou-se opacidade do eixo visual e necessidade de re-intevenção 6 olhos (12%), 4 olhos de crianças operadas com menos de 1 ano de idade (20% das crianças desta faixa etária) e 2 olhos de crianças maiores de 1 ano de idade (6,67% das crianças desta faixa etária). Conclusão: A técnica utilizada mostrou ser reprodutível, com complicações pósoperatórias leves e resultados refracionais adequados / Purpose: Evaluated the reproducibility, intraoperative and postoperative complications and refractive results by technique of primary IOL implantation followed by posterior capsulotomy and anterior vitrectomy via pars plana / plicata for treatment of congenital cataracts and development. Patients and methods: Children with congenital cataract and development, unilateral or bilateral with surgical indication aged zero to 12 years. Eyes less than 10 mm horizontal corneal diameter or other changes were excluded. Results: 50 eyes of 35 children and 18 males (51.42 %) and 17 female (48.58 %) . The age ranged from 2 months to 12 years. 20 eyes were of children under 1 year of age. 19 cases (76 %) had bilateral cataracts and 12 unilateral cases (24 %). No intraoperative complications were observed. Regarding postoperative complications, observed opacity of the visual axis and need to surgery in 6 eyes ( 12 % ) , 4 eyes operated under 1 year of age ( 20 % of children in this age group ) and 2 eyes older than 1 year of age ( 6.67 % of children in this age group ). Conclusion: The technique was shown to be reproducible, with mild postoperative complications and appropriate refractive results

Orientador: Antônio Carlos Lotelli Rodrigues / Banca: Silvan Artioli Schellini / Banca: José Honório Palma da Fonseca / Resumo: Objetivo: Avaliar a reprodutibilidade, complicações intra e pós-operatória e resultados refracionais da técnica de implante primário de LIO seguido de capsulotomia posterior e vitrectomia anterior via pars plana/plicata para tratamento da catarata congênita e do desenvolvimento. Pacientes e métodos: Crianças portadoras de catarata congênita e do desenvolvimento, uni ou bilateral com indicação de tratamento cirúrgico com idades de zero a 12 anos. Foram excluídos olhos com diâmetro corneano horizontal menor que 10 mm ou outras alterações. Resultados: 50 olhos operados de 35 crianças sendo 18 masculinos (51,42%) e 17 femininos (48,58%). A idade variou de 2 meses a 12 anos. 20 olhos eram de crianças com menos de 1 ano de idade. 19 casos (76%) apresentaram catarata bilateral e 12 casos unilaterais (24%). Nenhuma complicação intra-operatória foi observada. Em relação a complicações pós-operatórias observou-se opacidade do eixo visual e necessidade de re-intevenção 6 olhos (12%), 4 olhos de crianças operadas com menos de 1 ano de idade (20% das crianças desta faixa etária) e 2 olhos de crianças maiores de 1 ano de idade (6,67% das crianças desta faixa etária). Conclusão: A técnica utilizada mostrou ser reprodutível, com complicações pósoperatórias leves e resultados refracionais adequados / Abstract: Purpose: Evaluated the reproducibility, intraoperative and postoperative complications and refractive results by technique of primary IOL implantation followed by posterior capsulotomy and anterior vitrectomy via pars plana / plicata for treatment of congenital cataracts and development. Patients and methods: Children with congenital cataract and development, unilateral or bilateral with surgical indication aged zero to 12 years. Eyes less than 10 mm horizontal corneal diameter or other changes were excluded. Results: 50 eyes of 35 children and 18 males (51.42 %) and 17 female (48.58 %) . The age ranged from 2 months to 12 years. 20 eyes were of children under 1 year of age. 19 cases (76 %) had bilateral cataracts and 12 unilateral cases (24 %). No intraoperative complications were observed. Regarding postoperative complications, observed opacity of the visual axis and need to surgery in 6 eyes ( 12 % ) , 4 eyes operated under 1 year of age ( 20 % of children in this age group ) and 2 eyes older than 1 year of age ( 6.67 % of children in this age group ). Conclusion: The technique was shown to be reproducible, with mild postoperative complications and appropriate refractive results / Mestre

Abstract This study was undertaken to identify mechanisms of adhesion of intraocular lenses (IOLs) to the capsular bag after cataract surgery and IOL implantation. It was also done to challenge the sandwich theory presented for posterior capsular opacification (PCO): If the IOL is made of a bioactive material it would allow a single lens epithelial cell layer to bond both to the IOL and the posterior capsule at the same time. This would produce a sandwich pattern including the IOL, the cell monolayer and the posterior capsule. The sealed sandwich structure would prevent further epithelial ingrowth. The degree of bioactivity of the IOL could explain the basic difference in the incidence of PCO and capsulotomy rates with different IOL materials. The sandwich theory was put forward on the basis of a search for a keratoprosthesis material, which would allow maximal adhesion of the prosthesis to corneal tissue. Titanium and glass-ceramic coated titanium were found to develop better adhesion than poly (methyl methacrylate) (PMMA). The adhesion of PMMA to the corneal stromal tissue was loose, and down growth of corneal epithelial cells was seen around the prosthesis. The differences between various IOL materials were first tested with rabbit corneal tissue cultures. There was better adhesion of corneal tissue to soft, hydrophobic acrylate than to PMMA, heparin surface modified (HSM)-PMMA, silicone or hydrogel IOLs. To assess differences in protein adhesion to IOL surfaces, different IOLs were incubated for 24 hours with radioactive iodine labeled fibronectin. Soft hydrophobic acrylate (AcrySof®) showed the highest binding of fibronectin, and the differences relative to all the other materials were significant (p < 0.01-0.001), except to PMMA (p = 0.31). The sandwich theory and the results with rabbit corneal tissue cultures and the protein adhesion study in vitro were evaluated against the results found in pseudophakic autopsy eyes. Altogether, 70 autopsy eyes were analyzed. From 38 autopsy eyes containing PMMA, silicone, soft hydrophobic acrylate or hydrogel IOLs histological sections were prepared from the capsular bag and immunohistochemical analyses were performed for fibronectin, vitronectin, laminin and collagen type IV. A total of 152 specimens were analyzed. From 32 autopsy eyes containing IOLs made of PMMA, silicone, acrylate or hydrogel, IOLs were explanted from the capsular bag and immunohistochemical analysis was done on both sides of the IOLs for fibronectin, vitronectin, laminin or collagen type IV. Soft hydrophobic acrylate IOLs had significantly more adhesion of fibronectin to their surfaces than PMMA or silicone IOLs. Also, more vitronectin was attached to acrylate IOLs than to the other IOL materials. Silicone IOLs had more collagen type IV adhesion in comparison to the other IOL materials studied. In histologic sections a sandwich-like structure (anterior or posterior capsule-fibronectin-one cell layer-fibronectin-IOL surface) was seen significantly more often in eyes with acrylate IOLs than in PMMA, silicone or hydrogel IOL eyes. These studies support the sandwich theory for posterior capsule opacification after cataract surgery with IOLs. The results suggest that fibronectin may be the major extracellular protein responsible for the attachment of acrylate IOLs to the capsular bag. This may represent a true bioactive bond between the IOL and the lens epithelial cells, and between the IOL and the capsular bag. This may explain the reason for clinical observations of less posterior capsular opacification and lower capsulotomy rates with the soft hydrophobic acrylate material of AcrySof® IOLs compared to the other IOL materials studied.

In this retrospective study, medical records of 47 consecutive patients (94 eyes) who underwent simultaneous bilaterale small-incision cataract surgery between januar 2010 and December 2015 in outreach surgical camps in rural Cameroon were reviwed. At the 4 week follow-up, 84,04% of the eyes showed increased visual acuity of one line or more. No cases of post operative endophtalmitis were recorded. Under the strict observation of endophtalmitis prophylaxis, simultaneous bilaterale small-incision cataract surgery is an option to reduce the cataract blindness backlog in rural areas of developing countries.

Yes / Large changes in spectacle prescription can increase falls risk in older people. We investigated the effect of induced astigmatism (a common cause of distorted or blurred vision in older people) on locomotor stepping patterns to determine whether the orientation of astigmatic changes could have differential effects on gait safety when negotiating steps and stairs. Methods 10 older adults (mean age 76.0±6.4 years) walked up to and stepped onto a raised block whilst wearing their spectacle prescription and when blurred with ±3.00D cylinders at axes 45°, 90°, 135° and 180°. Gait measurements included foot placement before the block, toe clearance over the block edge and foot placement on the block. Results Induced astigmatism with axes at 90°, providing magnification in the horizontal meridian only, caused no change in stepping pattern. Induced astigmatism with axes at 180° caused foot placement changes in the anterior or posterior direction according to whether magnification was positive or negative in the vertical meridian (block perceived higher or lower respectively). Induced astigmatism with axes oblique at 45° and 135° (causing the block to be perceived as a parallelogram sloping downwards either to the right or left) caused gait changes in the anterior and posterior, vertical and lateral directions. Changes in lateral foot placement appeared to be an attempt to maintain constant foot clearance levels over the block edge by stepping over the perceived ‘lower’ side of the ‘sloping’ block. Conclusions Astigmatic changes with oblique axes had the greatest effect on gait. Clinicians, including optometrists, physiotherapists, occupational therapists and nurses should counsel older patients about the effects of astigmatism on gait safety. Furthermore, partial prescribing of astigmatic corrections should be considered to reduce the risk of falling.