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Visual function degrades with increasing age, in absence of frank disease, and affects both photopic and scotopic sensitivity. The mechanisms underlying these impairments may be related to biological (e.g., neural, optical) and environmental (e.g., smoking, dietary) factors. Recent evidence suggests that visual function may be improved following retinal carotenoid supplementation, both, in healthy and diseased eyes. Retinal carotenoids accumulate within the retina to form the macular pigment (MP) - a biomarker of antioxidant status of the eye and retinal disease risk. The objectives of this thesis were manyfold. First, the extent of vision loss (particularly scotopic sensitivity) in healthy ageing was examined. The results of this investigation showed that dark adaptation recovery slows with increasing age despite no significant change in visual acuity or fundus appearance. The technique described had excellent repeatability and correlated well with previous research. The potential link between MP and dark adaptation was also examined. The results showed that macular pigment optical density (MPOD) was correlated with a specific parameter of dark adaptation (S2) - a sensitive marker of functional degradation in normal ageing and retinal disease. The main part of this thesis sought to investigate the effect of MP augmentation on visual function in a large group of observers aged between 50 and 90 years old. The baseline data from this clinical trial revealed very interesting findings with regards to unhealthy lifestyle behaviours, health status and statin use. Subjects taking statins were identified (n = 25) and matched with 25 participants not using statins for age and body mass index. It was found that statin users had a higher proportion of males, higher prevalence of current smoking status and poorer general health (e.g. hypertension, high cholesterol and heart disease). Statin users also had significantly reduced MPOD, prolonged photostress recovery time, and deficits in a number of dark adaptation parameters. In a separate analysis of the whole group (n= 74, mean age 65.51), smokers were found to have reduced MPOD, slower S2, higher prevalence of high cholesterol and lower fruit and vegetable intake. MPOD was also reduced among obese subjects. The impact of MP augmentation on visual function in normal older subjects was assessed (n = 74, mean age 65.51) in a 12 month, randomized, double-blind, placebo-controlled study. Active formulation consisted of 20 mg lutein combined with vitamins and minerals. Data were collected at baseline, 6 months and 12 months. The results showed that, despite a 24% MPOD increase in the active group, there were no significant differences between the two groups over the three visits for any of the visual parameters. Given the increasing size of the older adult population in developed countries, research aimed at slowing or reversing age-related declines in vision is much needed both from an economical and psycho-social perspective. The results of the studies presented in this thesis show that lifestyle, health status and certain medications can adversely affect visual function in normal ageing. MP augmentation, however, had no effect on visual function. Further research is warranted, particularly paying close attention to subjects engaging in several unhealthy lifestyle/dietary behaviours, statin users and those with low MPOD and suboptimal visual function.

BACKGROUND- Motor vehicle crashes pose a serious public health problem. Many serious crashes are due to faulty driving by unfit operators, including several categories of neurological patients. Unfortunately, there seems to be little agreement among health professionals, driving experts, and state government on how to advise these individuals. REVIEW SUMMARY- This article reviews the question of driving in neurological patients. Decisions on driver fitness should be based on empirical observations of performance and not on criteria of age or medical diagnosis, which alone are unreliable predictors. Relevant data can be collected either on a road test or off-road, using different probes of vision and cognition, in the setting of a Department of Motor Vehicles office or medical clinic. The use of a driving simulator is also feasible. The predictive value of these performance assessments is a topic of active research. CONCLUSION- Understanding how performance data from off-road and on-road observations correlate with real-life crash risk is a key step toward developing safe, fair, and accurate means of predicting driver fitness. One potential benefit is the prevention of injury, and another is the preservation of mobility and independence of individuals whose licenses are being unduly revoked because of old age or illness.

Orientador: Fernanda Aparecida Cintra / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação / Made available in DSpace on 2018-08-08T04:07:37Z (GMT). No. of bitstreams: 1 Borges_SheiladeMelo_M.pdf: 637075 bytes, checksum: da2b46c5af56252ff050def17269c19e (MD5) Previous issue date: 2006 / Resumo: A prevalência da deficiência visual na população idosa é alta. A acuidade visual diminuída tem repercussões importantes na função visual e na capacidade funcional dos idosos. Objetivo - O objetivo do trabalho foi a avaliar a relação entre função visual e capacidade funcional em idosos em seguimento ambulatorial. Método - Foram entrevistados, por meio de instrumento próprio, 64 idosos em seguimento ambulatorial num hospital universitário. Os sujeitos foram divididos em dois grupos, conforme os valores obtidos na medida da AV: o grupo I composto pelos idosos com visão normal ou próxima do normal, e o grupo II formado por aqueles com baixa visão. Os dados foram submetidos à análise univariada, buscando-se as tendências da distribuição das diversas variáveis e os valores de posição e de dispersão de cada variável. Foram realizadas correlações bivariadas entre as variáveis, a fim de identificar as seguintes relações: 1. Entre os grupos (I e II) e os indicadores da condição visual (questões extraídas do instrumento NEI VFQ-25); 2. Entre os grupos (I e II) e a capacidade funcional (Medida da Independência Funcional ¿ MIF; Atividades Instrumentais de Vida Diária - AIVDs; Atividades Expandidas de Vida Diária ¿ AEVDs); 3. Entre indicadores da condição visual e a capacidade funcional. Na análise de covariância multivariada buscou-se verificar a influência das variáveis da função visual sobre as variáveis da capacidade funcional nos idosos. Resultados - Foram observadas diferenças significativas entre os idosos com visão normal ou próxima do normal (grupo I) e aqueles com baixa visão (grupo II), com respeito às variáveis: escolaridade (menor escolaridade no grupo II), indicadores da condição visual (menor auto percepção da visão, maior frustração, insegurança, limitação e dependência no grupo II), e AIVDs (menor escore ou maior dependência no grupo II). Observou-se, ainda, influência entre as variáveis da função visual (AV com os indicadores da condição visual), e entre AV com as AIVDs, sendo esta a única relação significativamente observada entre AV e os instrumentos de capacidade funcional utilizados nesse estudo. Conclusão ¿ houve influência da função visual na capacidade funcional nos idosos pesquisados / Abstact: The prevalence of visual deficiency in elderly people is high. The visual acuity reduced (VA) has important repercussions in the visual function and the functional capacity of the elderly. Objective - the objective is to evaluate the relation between the visual function and the functional capacity of the elderly in clinical segment. Method ¿ through own instruments, sixty-four elderly men and women were interviewed in clinical segment at an academic hospital. They were then divided into two groups in accordance to the values that were obtained through the measure of the VA: the first group consisted of elderly people with normal vision or close to the normal, and the second group was formed of those with low vision. The data were sent to the univariate analysis, looking for the tendencies of distribution of the diverse variables and the values of the position and dispersion of each variable. Bivariate correlations were made between the variables in order to identify the following relations: among the groups (I and II) and the indicators of visual condition (questions extracted from the NEI VFQ-25 instrument); among the groups (I and II) and the functional capacity (Functional Independence Measure ¿ FIM; Instrumental Activities of the Daily Life - IADL; Expanded Activities of Daily Life¿ EADL); among the indicators of the visual condition and the functional capacity. In the co-variance multivaried analysis to verify the influence of the variables of the visual function above the functional capacity of the elderly. Results ¿ significant differences between the elderly with normal vision or close to the normal (group I) and those with low vision (group II) were found: 1.educational level (lower in the second group); 2.indicators of the visual condition (lower autoperception of the vision, higher frustration, insecurity, limitation and dependence in the second group); 3.and IADL (lower score or higher dependence in the second group) It was also noticed the influence among the variables of the visual function (VA with the indicators of the visual condition), and between VA with the IADL, being this the only relation significantly observed between VA and the instruments of functional capacity utilized in this study. Conclusion ¿ the visual function has influence on the functional capacity of the elderly examined. / Mestrado / Mestre em Gerontologia

In contrast to mammals, zebrafish possess a high regenerative capacity even within the central nervous system including the retina. In the retina, lesions result in a loss of neurons and the subsequent activation of Müller glia, the retinal stem cells. Müller glia-derived progenitors differentiate into all types of retinal neurons. Eventually the anatomical tissue architecture is restored within a few weeks or months depending on the degree of lesion. However, little is known about how retinal lesions impair vision functionally, as well as how and to what extent visual function is restored during the course of regeneration, in particular in adult animals. Here, quantitative behavioral assays were applied to assess visual function during homeostasis and regeneration in adult zebrafish. While the dark-light preference test has been identified to be too variable to assess visual function, a novel visiondependent social preference test as well as an automated two level OKR-based vision test have proved to be more suitable. Two different lesion paradigms have been compared in this study: light-induced lesions that target photoreceptor cells and neurotoxin-mediated lesions that act in a concentration-dependent manner either affecting only inner retinal neurons or all retinal cell types. It could be shown that visual function was significantly impaired after light lesion but fully though gradually recovered within 28 days. Vision for easy conditions with high contrast and low level of detail, as well as color vision, was restored around 7–10 days post lesion while vision under more demanding conditions - with low contrast and high level of detailwas regained only from 14 days post lesion onwards. The corresponding retinal morphology was monitored in vivo using optical coherence tomography and revealed a close correlation between structure and function. Injection of neurotoxins resulted in a multitude of morphological changes that impeded the analysis of functional recovery. In general, restoration of visual function after neurotoxin-mediated lesion was limited and highly dependent on the initial degree of damage. As suggested by the behavioral studies, visual functions are, at least partially, restored after lesion. However, no conclusions can be drawn on the restoration of the underlying retinal circuitry. Hence, large-scale electrophysiological recordings using multielectrode arrays have been established for the adult zebrafish retina allowing the recording of spontaneous and light-driven activity. This technique can be exploited to analyze the restoration of signal processing of the retina in future studies. In addition, the established tools can be applied to characterize visual mutants and models of retinal degenerative diseases both morphologically and functionally as exemplarily demonstrated here for the blind atoh7 mutant. It was shown that the adult atoh7mutant largely resembles the larval phenotype and displays distinct alterations in optic tectum structure as well as impairments of social behavior. Altogether, the established vision-dependent behavioral assays suggest that the degree and kinetics of functional recovery are highly dependent on the lesion paradigm as well as quality of morphological restoration. In combination with the established multielectrode array recordings, the field is provided with new readouts to study functional recovery that can be used in addition to existing criteria to assess regeneration of the adult zebrafish retina. The established toolbox can furthermore be exploited to analyze retinal function not only in a regeneration context but also in visual mutants, disease models or ageing. Eventually, a deeper understanding of the regenerative processes in zebrafish will provide new perspectives for the development of therapies for retinal degenerative diseases.

Glaucoma is the leading cause of irreversible blindness worldwide but the effect of glaucoma on patients’ vision under suprathreshold conditions relevant to their natural visual environment is poorly understood. This project aimed to investigate and further understand the effects of glaucoma on three aspects of suprathreshold vision; apparent contrast of suprathreshold stimuli, detection and discrimination of image blur and crowding of peripheral vision. Psychophysical methods were employed to assess these three visual functions by measuring contrast matches of Gabor stimuli, blur detection and discrimination thresholds of edge stimuli and crowding ratios of Vernier targets. These measures were obtained from glaucoma observers tested within and outside of visual field defects and the data compared with healthy controls. Contrast matching ratios were similar between glaucoma and healthy age similar controls despite sensitivity loss in the glaucoma group. Blur detection and discrimination thresholds were similar between glaucoma observers’ tested within and outside of visual field defects and age-similar controls, though thresholds were slightly elevated for high contrast stimuli in the glaucoma visual field defect group. Crowding ratios were similar between participants with glaucoma and healthy young controls. The results demonstrate that aspects of suprathreshold visual function can be maintained in early glaucoma despite sensitivity loss at threshold. The results provide empirical evidence as to the asymptomatic nature of the disease in its early stages. It appears that in early glaucoma, there may be compensatory mechanisms at work within the visual system under suprathreshold conditions that can overcome loss of sensitivity at threshold. / The College of Optometrists

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No description available.

Background: Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany. Methods: Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies. Results: The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL −0.19 (0.006), ACD −0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (−0.66 (< 0.001)), ACD (−0.52 (< 0.001)) and ACV (−0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = −0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF −0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age. Conclusion: Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research. Trial registration: ClinicalTrials.gov # NCT01173614 July 28, 2010