Yes / Background: The aim was to profile transient accommodative axial length changes from early adulthood to advanced presbyopia and to determine whether any differences exist between the responses of myopic and emmetropic individuals. Methods: Ocular biometry was measured by the LenStar biometer (Haag-Streit, Switzerland) in response to zero, 3.00 and 4.50 D accommodative stimuli in 35 emmetropes and 37 myopes, aged 18 to 60 years. All results were corrected to reduce errors arising from the increase in crystalline lens thickness with accommodation. Accommodative responses were measured sequentially by the WAM 5500 Auto Ref/Keratometer (Grand Seiko, Hiroshima, Japan). Results: Axial length increased significantly with accommodation (p < 0.001), with a mean corrected increase in axial length of 2 18 μm and 8 16 μm observed at 3.00 and 4.50 D, respectively. The magnitude of accommodative change in axial length was not dependent on refractive error classification (p = 0.959); however, a significant reduction in the magnitude and variance of axial length change was evident after 43 to 44 years of age (p < 0.002). Conclusion: The negative association between transient increase in axial length and age, in combination with reduced variance of data after age 43 to 44 years, is consistent with a significant increase in posterior ocular rigidity, which may be influential in the development of presbyopia. / DL received funds from the College of Optometrists, UK

Objetivo: Estudar maneiras distintas de se corrigir a presbiopia durante a facoemulsificação, através da avaliação do desempenho visual de quatro diferentes modelos de lentes intraoculares; assim como determinar a influência da pupila na recuperação visual e comparar a independência ao uso de óculos após o implante bilateral. Casuística e Métodos: Estudo prospectivo, consecutivo, randomizado que avaliou 60 pacientes (120 olhos) divididos em quatro grupos: lentes multifocais Restor +3, Restor +2.5, monovisão com a lente SN60WF e a pseudoacomodativa Crystalens XO. Foram incluídos pacientes que apresentavam catarata nuclear NI, NII ou cortical similar, que foram submetidos à avaliação oftalmológica completa no pré- operatório e com 1, 3 e 12 meses após a cirurgia. Antes do procedimento, os seguintes exames foram realizados: biometria óptica (Lenstar 900), microscopia especular, avaliação da região macular e das camadas de fibras nervosas por meio de Tomografia de Coerência Óptica (OCT), avaliação da sensibilidade ao contraste (Software Macular Mapping Test) e pupilometria dinâmica (ISCAN INC). As cirurgias foram realizadas por dois cirurgiões, em caráter ambulatorial. Durante o seguimento, nas visitas de 1, 3 e 12 meses após a cirurgia, foram realizadas medidas de acuidade visual longe e perto, mono e binocular, curva de desfoco monocular e pupilometria; e foi aplicado um questionário de satisfação baseado do Visual Functioning Questionnaire - 25 (VFQ 25), assim como medidas de sensibilidade ao contraste. Resultados: Dos 120 olhos selecionados, 114 foram operados, 106 avaliados com um mês de cirurgia, 100 com três meses e 45 pacientes (90 olhos) chegaram a última avaliação com um ano de follow-up. As médias da acuidade visual para longe sem correção binocular foram de 0,09 ± 0,04; 0,09 ± 0,03 e 0,11 ± 0,03 logMar para as lentes Restor +2.5, Restor +3 e SN60WF, respectivamente. Entre elas não se observou diferença significativa. Já para a lente Crystalens XO, a média foi de 0,24 ± 0,04 logMar, constatando-se sua inferioridade para longe de forma significativa estatisticamente em relação às demais. Este resultado foi atribuído à pobre previsibilidade refracional da lente pseudoacomodativa (-1.33 ± 1.37 dpt). Para perto, não houve diferença entre os grupos Restor +3 e monovisão, e as lentes Restor +2.5 e Crystalens apresentaram piores resultados que as duas primeiras, de forma significativa. As médias para perto, em logMar foram de 0,08 ± 0,01; 0,17 ± 0,04; 0,22 ± 0,04 e 0,23 ± 0,07 para as lentes Restor +3, SN60WF, Restor +2.5 e Crystalens, respecivamente. A curva de desfoco das lentes multifocais Restor +3 e Restor +2.5 apresentou dois picos de acuidade visual máxima; o primeiro vértice próximo a zero e o segundo em -2.5 dpt para a Restor +3 e -2 dpt para a Restor +2.5. O segundo vértice da Restor +3 foi mais acentuado em relação ao da Restor +2.5. Já o modelo Crystalens apresentou a curva de desfoco com um pico de acuidade visual máxima, semelhante às lentes monofocais SN60WF, ambas com vértice próximo ao equivalente esférico programado. A partir da curva de desfoco, somando-se as acuidades visuais entre os dois picos de melhor visão, foi criado um índice, denominado Índice de Multifocalidade. O intuito foi criar um indicador de qualidade de visão longe, intermediário e perto para as diversas lentes. O modelo Restor +3 obteve o melhorResumo índice entre as lentes estudadas, porém não mostrou diferença significativa em relação à Restor +2.5, que, por sua vez, não evidenciou diferença quanto à Crystalens. A lente SN60WF teve o pior índice. Já em relação a pupila, não houve interferência de sua amplitude de contração no pré-operatório com as acuidades visuais longe e perto após a cirurgia. Contudo, o tamanho da pupila contraída demonstrou correlação com o índice de multifocalidade. A avaliação da sensibilidade a estímulos de baixo contraste (10%) no campo visual central (8 graus) não foi diferente entre os grupos, tanto no pré quanto no pós-operatório. E em relação à presença de halos e glare, os grupos Restor +3 e +2.5 apresentaram incidência de 26% e 43%, respectivamente; já no grupo SN60WF não houve relato. A satisfação com a performance visual para longe foi de 78% no grupo Crystalens, 80% no grupo monovisão e 90% para as multifocais Restor +3 e Restor +2.5. Para perto, 100 % dos usuários da Restor +3, 80% da monovisão, e 50% dos grupos Restor +2.5 e Crystalens estavam satisfeitos. Finalmente, entre as maneiras distintas de se corrigir a presbiopia na facoemulsificação, o grupo Restor +3 atingiu 93% de independência do uso de óculos após a cirurgia. Inesperadamente e de acordo com os resultados, o modelo Restor +2.5 demonstrou baixa probabilidade de independência (14%). Para a monovisão e Crystalens, 30% e 50%, respectivamente. Conclusões: Tanto a lente multifocal Restor +3 quanto a monovisão com a SN60WF foram eficazes de forma semelhante na correção da presbiopia, porém o modelo Restor +3 proporcionou maior probabilidade de independência ao uso de óculos. Os modelos Restor +2.5 e a Crystalens XO pseudoacomodativa foram inferiores que as duas primeiras, pela lente multifocal Restor +2.5 apresentar resultados aquém do previsto para perto, com baixa independência do uso de óculos; e a Crystalens mostrar imprevisibilidade refracional biométrica, comprometendo a visão de longe dos usuários. A respeito da dinâmica pupilar, as medidas do pré e pós-operatório não evidenciaram interferência no desempenho visual das lentes multifocais, monovisão e pseudoacomodativa; exceto no índice de multifocalidade, onde as pupilas contraídas apresentaram correlação com os resultados. / Objective: Study different ways of correcting presbyopia in phacoemulsification by comparing visual performance of four different models of intraocular lenses; as well as to determine the influence of the pupil on visual recovery and to compare the independence of glasses after bilateral implant. Casuistic and Methods: Prospective, consecutive, randomized study with 60 patients (120 eyes) divided into 4 groups: Restor +3 and Restor +2.5 multifocal lenses, monovision with SN60WF and Crystalens XO pseudoacommodative lens. Patients who had nuclear NI, NII or similar cortical cataract were submitted to a complete ophthalmologic evaluation in the preoperative period and at 1,3 and 12 months after surgery. Before procedure, the following tests were performed: optical biometry (Lenstar 900), specular microscopy, analyse of macular region and nerve fiber layers with Optical Coherence Tomography (OCT), contrast sensitivity (MMTest Software) and pupilometry dynamics (ISCAN INC). Surgeries were performed by two surgeons. During the follow-up, visits of 1, 3 and 12 months were measured far and near, mono and binocular visual acuity, defocous curve, pupilometry, satisfaction questionnaire was applied based on Visual Functioning Questionnaire - 25 (VFQ 25) as well as a contrast sensitivity measurements (Macular Mapping Test). Results: Of the 120 eyes selected, 114 were operated, 106 were evaluated at 1 month of surgery, 100 at 3 months, and 45 pacients (90 eyes) achieve the last evaluation at 1 year follow-up. The mean visual acuity for far without binocular correction was 0.09 ± 0.04; 0.09 ± 0.03 and 0.11 ± 0.03 logMar for the lenses Restor +2.5, Restor +3 and SN60WF respectively. Between them there was no difference. For the Crystalens XO lens, the mean was 0.24 ± 0.04 logMar, showing its inferiority statistically significantly different than the others. This result was attributed by the poor refractive predictability of the pseudoacommodative lens (-1.33 ± 1.37 dpt). For close, there was no difference between the Restor +3 and monovision groups, and the Restor +2.5 and Crystalens lenses were worse than the first with statistical significance . The means for near were 0,08 ± 0,01; 0.17 ± 0.04; 0.22 ± 0.04 and 0.23 ± 0.07 for the Restor +3, SN60WF-, Restor +2.5 and Crystalens lenses. The defocous curve of the multifocal lenses Restor +3 and Restor +2.5 had 2 peaks of maximum visual acuity, the first in zero and the second close to -2.5 dpt for Restor +3 and -2 dpt for Restor +2.5. The second vertex of Restor +3 was more pronounced than Restor +2.5. The Crystalens group presented a defocous curve with only 1 peak of maximum visual acuity, as well as the SN60WF monofocal lenses, both with a vertex near the programmed spherical equivalent. From the defocous curve, adding the visual acuity between the two best view peaks, an index was created, called Multifocality Index. The aim was to create a far, intermediate and close quality index for the various lenses. Restor +3 obtained the best index, but that was no significantly different than Restor +2.5, which had no difference with Crystalens. SN60WF achieved the worst index. Regarding the pupil, did no notice interference of its preoperative contraction amplitude with the visual acuities far and near after the surgery. However, the size of contracted pupil had a statistically significant correlation with the multifocality index. The sensitivity to low contrastAbstract stimuli (10%) in the central visual field (8 degrees) was no different between the groups, both in the pre and postoperative periods. About presence of halos and glare, the multifocal lenses Restor +3 and Restor +2.5 showed 26% and 43% respectively. No cases were reportaded with model SN60WF. The satisfaction with the far visual performance was 78% in the Crystalens group, 80% for monovision and 90% in the multifocal lenses Restor +3 and +2.5. For near, 100% of Restor +3 users, 80% of monovision, and 50% of Restor +2.5 and Crystalens groups were satisfied. Finally, among the distinct ways of correcting presbyopia in phacoemulsification, the Restor +3 group showed that 93% of their users achieved independence of the glasses after surgery. Unexpectedly and according to the visual results, the Restor +2.5 model showed a low probability of independence, 14%. For monovision and Crystalens, 30% and 50% respectively. Conclusions: Both Restor +3 and monovision with SN60WF were similarly effective for correction of presbyopia, but the Restor +3 model provides a greater probability of independence from wearing glasses. The Restor +2.5 and pseudoacommodative models Crystalens XO were worst than the first two, because the multifocal Restor +2.5 presented results below the predicted for near, with low independence of the use of glasses; and model Crystalens unexpected biometric refractive unpredictability, compromising the view from far away from users. Regarding the pupillary dynamics, the pre and postoperative measurements showed no interference in the visual performance of multifocal, monovision and pseudoacommodative lenses; except in the multifocality index, where pupils contracted had a correlation with the results.

The goal of this project was to develop techniques and instrumentation to measure the elastic properties of the lens and lens capsule in situ and their changes with age using Atomic Force Microscopy (AFM). The studies include the construction, characterization, and calibration of laboratory-based Atomic Force Microscope (AFM) to measure mechanical properties of ophthalmic tissues. Atomic Force Microscopy is a nanoscale imaging technique that has been applied to mechanical property measurement through nanoindentation. Young's modulus of elasticity is determined by monitoring the cantilever deflections when it contacts the sample. The studies also include the development of tissue preparation techniques to enable measurement of the lens elasticity using AFM. This study found that lens capsule elasticity decreases with age, outer lens cortex elasticity remains constant with age, and the inner lens cortex is stiffer than the outer lens cortex. The effect of the changing biometry and mechanical properties with age was investigated by developing a mathematical model of accommodation. These changes will be the limiting factor to accommodative amplitude. Changes in lens capsule mechanical properties will affect the maximal accommodative amplitude in older eyes.

The goal of this project is to obtain quantitative images of the lens and the ciliary body to validate EVAS-II (Second generation Ex Vivo Accommodation Simulator). To accomplish this goal it was necessary to develop methods, instrumentation and image processing techniques to acquire 3D images in EVAS-II, using UBM (Ultrasound Bio Microscope), and to apply these techniques to non-human primate eyes. The lens studies included measurement of speed of sound in the lens to reconstruct accurate images of the lens, development of instrumentation to measure the un-distorted lens shape and development of a mathematical model to quantify the whole lens shape. Speed measurements showed that the speed of sound exhibits a gradient profile in the equatorial plane, similar to refractive index and protein distributions in the lens. Lens shape measurements showed that the UBM can be used to accurately measure thickness, diameter, cross-sectional area, volume and surface area of the lens. The ciliary body studies included development of instrumentation and algorithms to obtain 3-D images of tissue in EVAS-II and development of methodology to quantify ciliary body movement during stretching. Studies showed that the accommodation process in young baboon eyes in EVAS-II is comparable to the in vivo process in rhesus monkeys. The UBM can be used to obtain reliable quantitative information about the lens and the ciliary body. 3-D UBM enables monitoring of ciliary body motion of the entire accommodative apparatus.

No description available.

No description available.

Introduction: The aim of the present study was to determine adaptive gait changes in long-term wearers of monovision correction contact lenses by comparing gait parameters when wearing monovision correction to those observed when wearing binocular distance correction contact lenses. Methods: Gait and toe clearance parameters were measured in eleven participants (53.5 ± 4.6 years, median monovision wearing time 5 years) as they repeatedly walked up to and onto a raised surface with either monovision or distance correction. Results: Compared to distance correction, monovision resulted in a large reduction in stereoacuity from 17¿ to 87¿, a slower walking velocity (p = 0.001), a reduced horizontal toe clearance of the step edge (p = 0.035) and, for trials when monovision correction occurred first, a 33% greater variability in vertical toe clearance (p = 0.021). Variability in some gait data was large due to certain study design features and learning effects. Conclusion: A slower walking velocity with monovision correction suggests participants became more cautious, likely as a result of the significantly reduced stereoacuity. The decreased horizontal toe clearance and increased vertical toe clearance variability suggests that monovision correction may cause a greater likelihood of hitting step edges and tripping during everyday gait. Recommended study design features are suggested for future adaptive gait studies to increase the precision of the data and to attempt to minimize the effects of learning from somatosensory feedback.

INTRODUÇÃO: A presbiopia pseudofácica, imposta pela extração do cristalino e implantação de uma lente intraocular monofocal, representa uma relativa limitação da cirurgia de catarata moderna. Diversos métodos para compensação de tal fenômeno já foram descritos. Nesse estudo, avaliamos a eficácia de um implante intraocular estenopeico em promover ampliação da profundidade de foco, e seu impacto no desempenho visual. MÉTODOS: Foram selecionados 10 pacientes hígidos, com boa saúde ocular, previamente submetidos a cirurgia de catarata bilateral com implante de lente intraocular monofocal, os quais apresentavam limitação da acuidade visual para perto. Os pacientes foram submetidos a implantação monocular do diafragma intraocular estenopeico XtraFocus®, no sulco ciliar. As variáveis avaliadas foram acuidade visual, refração subjetiva, sensibilidade ao contraste, amplitude de pseudoacomodação (curva de defocus), estereopsia, campimetria computadorizada, teste de efeito Pulfrich, e avaliação subjetiva do desempenho visual, através da aplicação de questionário. RESULTADOS: Houve significativa melhora da acuidade visual para perto, com 7 pacientes alcançando acuidade visual sem correção para perto de 20/30, no olho operado. Não houve impacto significativo na refração subjetiva, sensibilidade ao contraste e estereopsia. A perimetria computadorizada evidenciou redução de sensibilidade retiniana difusa, no olho operado. A percepção subjetiva do desempenho visual após o tratamento foi favorável, com impacto positivo nas atividades diárias. Não foi observada indução de efeito Pulfrich. CONCLUSÕES: O implante estenopeico estudado foi capaz de promover ampliação da profundidade de foco, com aprimoramento da acuidade visual para perto. O implantação cirúrgica se mostrou segura, sem ocorrência de eventos adversos significativos. Os resultados sugerem que uma maior independência de óculos pode ser alcançada caso a técnica seja aplicada em pacientes portadores de miopia de pequena magnitude. Este achado está em conformidade com trabalhos prévios envolvendo dispositivos estenopeicos. Apesar da limitação à entrada de luz imposta pelo orifício estenopeico, a percepção de luminosidade não é proporcionalmente impactada. Entretanto, em condições de baixa luminosidade, pode haver uma percepção monocular de escuridão / INTRODUCTION: Pseudophakic presbyopia, imposed by crystalline lens extraction and implantation of an artificial monofocal intraocular lens (IOL), represents a relative limitation of modern cataract surgery. Several methods of compensation of this phenomenon have been proposed. In this study, we evaluate the efficacy of a pinhole intraocular implant in promoting depth of focus extension, and its impact in visual performance. METHODS: A selection of 10 healthy patients, with no ocular comorbidity, previously submitted to bilateral cataract surgery and monofocal IOL implantation, presenting with near vision limitation, was carried out. Patients underwent monocular implantation of the XtraFocus® pinhole implant, in the ciliary sulcus. Outcome variables were visual acuity, subjective refraction, contrast sensitivity, amplitude of pseudoaccommodation (defocus curve), stereoacuity, automated perimetry, Pulfrich effect testing and subjective visual performance evaluation with a questionnaire. RESULTS: A significant improvement in near visual acuity was observed, with 7 patients reaching 20/30 uncorrected near visual acuity, in the operated eye. There was no significant impact in subjective refraction, contrast sensitivity and stereoacuity. Automated perimetry revealed a reduction of overall retinal sensitivity, in the operated eye. Subjective assessment of visual performance was favourable, with positive impact in daily activities. Induction of Pulfrich effect was not observed. CONCLUSIONS: The pinhole implant evaluated in this study was able to provide depth of focus extension, and enhance near visual acuity. Surgical implantation was safe, with no occurrence of significant adverse events. Results suggest that a greater level of spectacle independence may be achieved if this approach is combined with low levels of myopia. This finding is in accordance with other studies involving small aperture optics. In spite of the reduction of light entrance caused by the pinhole implant, the overall brightness sensation is not proportionally impaired. However, under low light conditions, a monocular darkening perception can occur

Presbyopia is the progressive decrease in accommodative ability with age, and it implies a major loss of visual function. Presbyopia is the only condition of the eye which affects everyone who lives beyond 50 years of age. As part of a joint effort, the Ophthalmic Biophysics Center at the Bascom Palmer Eye Institute and the Vision Cooperative Research Centre at the University of New South Wales, developed two different ex-vivo accommodation simulators (EVAS) to examine the mechanisms of accommodation and presbyopia, and to test and validate new ophthalmic surgical procedures such as lens refilling. The purpose of this thesis is to mechanically and optically calibrate the second generation instrument (EVASII), and to compare it to the first generation design (EVASI). To validate the optical measurements of EVASII, an optical calibration has been performed, yielding a lens power measurement system with a mean accuracy of ±0.56D. To enhance the optical capabilities and tissue dissection options, the mechanics of mounting the tissue has been improved by using magnetic mounts, and the mechanical calibration of EVASII, yielded a force measurement system with a mean uncertainty of ±0.81g Also, a comparison of EVASII and EVASI has been performed, showing that the results of the two systems are significantly different; however, both systems successfully simulate accommodation. Thus, general trends concerning efficacy and optimization of surgical procedures as well as age related accommodative changes can be compared for each individual system.

Background: The World Health Organization estimates that there are 517 million people in the world who are visually impaired due to uncorrected presbyopia. Equal sphere ready-made bifocal and single vision reading spectacles are an inexpensive alternative to custom made spectacles. Methods: A visual satisfaction questionnaire was administered before patients were examined at an outreach clinic and again after ready-made bifocals or reading spectacles were dispensed. The results of both sets of questions along with presenting acuities, corrected acuities, refractive data, and willingness to pay were analyzed. Results: There was an unmet need of 38% (of the 338 subjects that needed glasses only 208 had them). There was no gender bias; the unmet need was higher in the rural areas (47% rural, 36% urban). Those who could not read were 3.4 times less likely to have the glasses they needed than the literate. Unmet need decreased with every level of education. Those without any schooling showed 77% prevalence of unmet need and those with university education had an unmet need rate of 32%. Ready-made spectacles were dispensed to 89.5% of those examined. The ready-made bifocals were very well accepted, with the percentage of subjects giving the highest satisfaction rating improving from a presenting value of 11% to 89.4% with the bifocals at distance and from 6.6% to 89.4% at near. Distance visual acuity of 20/40 or better improved from the presenting value of 60% to 84.5% and near vision of 20/40 or better improved from the presenting value of 44% to 97%. With ready-made single vision readers, functionally good near vision (20/40 or better) improved from a presenting value of 38% to 97%. The highest ranking for near satisfaction improved from 6.3% to 86.6%. The subjects indicted that they would be willing to pay US$18.39 to replace the bifocals and US$16.67 to replace the readers. Conclusion: There is a high unmet need for vision correction in the population over age 35 in Nicaragua. Dissatisfaction with distance and near vision is very high. Although custom made glasses are ideal, ready-made bifocals and ready-made single vision readers are an acceptable and affordable alternative.