Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 129-137). Available also in a digital version from Dissertation Abstracts.

Purpose: The prevalence of age-related visual impairment is projected to increase as the Canadian population ages. As a result, the demand for low vision service is also projected to increase. However, there is a lack of healthcare planning regarding vision rehabilitation in Canada. The current study is the first study that describes optometric low vision services across Canada. The primary purposes of this study were to determine the provision of low vision services by optometrists in Canada, the barriers to providing low vision services and the pattern and perception of referrals to specialised low vision services. The secondary purposes of this study were to examine regional differences in low vision practice and referral patterns, and to identify predictive factors associated with the extent of optometric low vision care. Methods: Practising optometrists across Canada (n=1839 or 40.5% of the Canadian optometric population) were randomly sampled so as to obtain approximately equal responses from the Western Provinces, Ontario, Quebec and the Eastern provinces. Between October 2010 to January 2011, optometrists were invited to participate in a 30-item questionnaire that included questions on personal profile, primary practice profile, types of patients seen, levels of low vision services offered, patterns of referral and barriers to provision of low vision care. Descriptive statistics were used to describe the current landscape of optometric low vision care. Chi-square analyses were used to identify any regional differences in pattern of low vision provision and/or referrals. Multivariate logistic regression was used to determine the predictive factors associated with the extent of optometric low vision care. Written comments on low vision education and provision of low vision services were first coded to represent relevant categories of information emerging from the written data. Then the patterns of coding were grouped into common themes. Results: A total of 459 optometrists responded (24.8%). Optometrists estimated that 1% (range 0-100%) of their patients were patients with low vision, yet also estimated that 10% of their patients had a best corrected visual acuity of ???6/12. Almost three-quarters of respondents would manage a hypothetical patient with minimal visual disabilities and simple visual goals with high-powered additions and lighting; however, the proportion of those who would manage with the same patient with magnifiers and filter lenses dropped to 43%. The most frequently cited barriers to providing more extensive low vision services were found to be related to financial non-viability, lack of affordability by the patient and the time-consuming nature of conducting a low vision assessment. The percentage of respondents who cited no interest in low vision was 33.5%. Many respondents would like to see more continuing education on low vision, preferably through a hands-on approach. The most frequent site of referral was CNIB (81.9%), although most of the respondents (57.1%) rarely (0-5% of the time) or almost never (0-25% of the time) received a written report from the low vision service providers. Chi-square analyses revealed that optometrists in Quebec tended to refer eligible patients to government-sponsored vision rehabilitation centres, while optometrists in Eastern provinces tended to manage patients on their own. The predictive factors associated with the extent of optometric low vision care were advanced years of practice (16+ years), having local low vision optometrists/ophthalmologists within one-day???s travel, working in a practice within a population of less than 50,000 and working in a non-solo practice. Conclusions: This study documents that optometrists may be undertaking more low vision (LV) in patients with relatively good vision than they tend to label as LV. Vision rehabilitation is of interest to a large portion of optometrists across Canada. To translate the interest into practice, barriers identified by the current study must be addressed.

Thesis (Ph.D.)--University of Melbourne, Centre for Eye Research Australia, Dept. of Opthalmology 2010. / Typescript. Includes bibliographical references (p. 251-274)

This collection of essays is both a personal chronicle of vision loss and an investigation into the human eye. Delving into the history of corrective lenses, eye contact, crying, ocularcentrism, the typewriter, Mr. Magoo, and off-label drug use, these essays examine the wide variety of ways we relate to eyeballs, vision, and blindness.

This research was designed to address important issues for the effective prescription of, and training in the use of, magnifiers for reading patients with visual impairment. The emphasis was on the development of simple methods of assessment and training that could be easily implemented, at no great cost, by low vision practitioners in clinical practice. To ensure that the results would be widely applicable, the research focused on subjects with age-related macular degeneration (AMD) using stand magnifiers (being the most common cause of low vision and the most commonly prescribed magnifiers respectively). From this research, modifications to the current methods of reading rehabilitation are suggested to more effectively improve low vision reading for the millions of people with low vision around the world. The magnification and reading performance achieved with the magnifier determined by the fixed acuity reserve method was as valid as that achieved with the magnifier determined by the individual acuity reserve method. The fixed acuity reserve is a simpler method to calculate the required magnification, as it requires only near visual acuity and the patient's goal reading task. This method was primarily used to select the appropriate illuminated stand magnifiers for the subjects participating in the subsequent studies and is recommended for use as the starting point in clinical low vision practice. The main study of this thesis was a longitudinal investigation of the benefit of large print reading practice on reading performance with stand magnifiers. Instead of the intensive training programs on magnifier use which have been suggested by previous studies, this study aimed to investigate the effect of simple large print reading practice, under either full or restricted field of view (the latter simulated by a practice stand), on reading rate with stand magnifiers for subjects with AMD. The experimental hypothesis was that reading practice prior to the prescription of stand magnifiers would improve reading performance with the stand magnifiers for subjects with AMD. As previous studies have shown, reading rate reduced when a stand magnifier was first introduced. One week of reading practice on large print, with or without a reduced field of view, gave an improvement in reading rate with the stand magnifier for passages of text (such that the reading rates with and without magnifiers were not significantly different). There was a suggestion that this practice may give a more rapid improvement in reading rate than that achieved by the control subjects who did not do any large print reading practice, but this did not reach statistical significance. Even very brief reading with the stand magnifiers by the control subjects gave some improvement in reading rate. Therefore, home or in-office reading practice on large print or with magnifiers is recommended for patients with AMD before magnifiers are prescribed. Subjects who had neither reading practice nor exposure to the magnifier prior to its prescription required two weeks practice using their stand magnifiers to achieve their maximum reading rate. This suggests that home practice in using stand magnifiers is beneficial and a follow up visit is recommended two weeks after the provision of a magnifier to assess any change in reading rate. If no improvement in the magnifier reading rate is found or the rate is less than the reading rate on large print without a magnifier, further investigations of the patients' vision and/or their magnifier manipulation strategy are necessary. In the last study, a simple method aimed at alleviating difficulties with magnifier manipulation and navigation, the attachment of a line guide to the base of the stand magnifier, was investigated using both objective methods (recording magnifier movements and reading rate measures) and subjective methods (simple questionnaire). Although there was no improvement in the objective measures of reading or navigation performance with the line guide, more than half of the subjects with low vision preferred to have the line guide on their stand magnifiers. This suggests that the objective measures might not be sensitive enough to predict the subjective response, or that other factors that were not measured in this study influenced subjects' preferences in selecting the line guide (e.g., psychological support provided by the line guide in reading orientation). Clinically, the subjective response of patients to the use of low vision aids as well as their motivation are important criteria for success in low vision rehabilitation. There was a tendency for less experienced users to prefer the line guide to assist their use of the stand magnifier for reading. Therefore, a line guide could be offered as a preliminary training aid when stand magnifiers are first prescribed for AMD patients. Possible improvements to the design of the line guide were identified. Further research is required to assess the benefits of this or similar devices for new magnifier users and to understand the difficulties that people with visual impairment have with page navigation in order to determine improved methods of training navigation strategies. The unique contribution of this study to the field of low vision rehabilitation is that the benefit of short-term reading practice, on large print or with magnifiers, as simple, cheap methods of enhancing reading performance with stand magnifiers was demonstrated. The results of this study have led to the development of recommendations for assessing and training AMD patients who are prescribed stand magnifiers.

Quality of life (QoL) questionnaires have been suggested as the most appropriate way to measure the effectiveness of low vision rehabilitation. However, several research studies have not been able to detect differences in effectiveness between rehabilitation strategies. The hypothesis of this study is that there are other factors, unrelated to vision, influencing the scores obtained in these questionnaires and masking the changes achieved by rehabilitation. The suggestion is that patients' realistic acceptance of, and successful adaptation to, their visual loss is influenced by psychosocial factors such as; personality, religious beliefs, social support, general health (i.e. mental and physical), understanding of their eye condition, level of education, and financial status. Concurrently, a parallel study was conducted with children. As with the adult arm, the aim of the study was to understand whether quality of life, and social behaviour and relationships in children with a visual impairment were related to the vision loss, vision rehabilitation, or non-visual factors. Patients attending the Manchester Royal Eye Hospital low vision clinic between May 2009 and August 2010, were recruited: 448 patients between 18 and 96 years old, with best-corrected binocular visual acuity smaller or equal to6/18, and 62 children between 5 and 16 years old. Telephone delivery of previously validated questionnaires was used with adult patients and parents of child patients; face-to-face interviews were completed by children. Both studies showed how psychosocial factors were stronger determinants of quality of life in people with low vision, than traditional low vision rehabilitation using optical aids. In the case of adults, physical and mental health appeared to be major predictors of quality of life, adaptation to the vision loss and participation restriction. In the case of children, visual acuity at distance and near, contrast sensitivity (CS), age, and parents' coping strategies appeared to determine quality of life and children behaviours. The final element of this work was a pilot study to attempt to address issues causing poor quality of life. Seventy-one participants who scored low in the Low Vision Quality of Life Questionnaire (LVQOL-25) (i.e. below 62.5) were given the opportunity to enrol for the Expert Patient Programme, which is a self-management programme aimed at adults with chronic health problems or disabilities. Only 2 participants expressed an interest in the programme, and none of them actually took part.

No description available.

The number of individuals facing vision loss as adults is increasing, and the need for these adults to have access to training and skills to aid in their adjustment process is prevalent. Guided by the tenets of connectivism, this phenomenological study examined current trends in social networking and the possibilities that are available to adults adjusting to low vision by using technology as a means for continued learning, social interaction, and professional connections. The main research question focused on the participants' perception of the adjustment process and their ability to learn and use technology. Data were collected through semi-structured interviews of 10 adults who had low vision and had attended some form of intervention. The experiences were recorded through the use of reflection that included memoing and inductive coding where themes emerged during the field process. NVivo software was utilized to clarify and present details about themes and patterns presented during the interview discussions. These themes detailed the participants' feelings of confidence and self expressed level of skills needed to use technology; the barriers to using technology, such as cost and time; and benefits of staying connected with technology. The findings from this study suggested that the ability to stay connected and to access information outweighed the barriers, although the participants expressed frustration with technological issues. The study contributed to an area of research that supports the benefits of continued training for adults adjusting to low vision. A process of training could be implemented that would involve general technology as well as assistive technology assisting individuals with continued success in their daily lives.

This study evaluated whether cortical reorganization occurs in response to macular degeneration (MD), a progressive disorder of the retina that results in central vision loss. Past research has observed the ability of V1 to adapt to retinal damage, demonstrating that deafferented cortex is activated by the stimulation of intact retinal areas. It is still unclear, however, if and to what degree cortical reorganization is associated with specific forms of macular degeneration. This study evaluated the retinal health of MD participants (both age-related and juvenile) as well age-matched controls with computerized microperimetry. Contrast-reversing stimuli were then presented to different parts of the visual field while participants were scanned with functional magnetic resonance imaging (fMRI). For MD participants, stimulation of peripheral retinal areas elicited activation in deafferented cortex. This activation occurred for retinal areas adapted for eccentric viewing (preferred retinal locations), but not in preserved retina at the same eccentricity. These findings add to the scientific knowledge of plasticity in sensory systems by supporting an experience driven understanding of cortical reorganization. They could also have a meaningful impact on how macular degeneration is treated by informing the design of therapeutic training regimes.

No description available.