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Results for “Persons with Visual Disabilities”

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PubMed2006

Utilization of eye care services in Victoria.

PURPOSE: To determine baseline eye care utilization by older Victorians in order to assess change in 2 years after an eye health promotion campaign. METHODS: A letter of invitation to participate was sent to all people aged 70-79 years in randomly selected Melbourne postcode areas. A questionnaire was designed to allow gathering of eye health-related information. Eye exams included autorefraction, frequency doubling technology and non-mydriatic fundus photography. Results were compared with the Melbourne Vision Impairment Project . RESULTS: A total of 1695 people with a mean age of 74 years were recruited. The overall proportion with visual impairment was 8% (134/1695), of which 27% (36/134) was due to non-refractive causes. Only 31% (11/36) of visually impaired people knew about low-vision services, of whom 20% (7/36) had used them. Of all people with diabetes, only 52% (96/184) had a dilated eye exam within the recommended 2 years (Melbourne Vision Impairment Project 44%). CONCLUSIONS: Compliance rates with recommendations for 2-yearly eye exams for people with diabetes have not improved since the last major eye health study in Victoria 10 years ago. The same is true for the rate of undiagnosed glaucoma, suggesting that messages about eye examinations need to be promoted for older people at high risk of vision loss, for example, those with diabetes and at risk of vision loss from glaucoma.

Aged↗
PubMed2006

Prevalence and causes of visual impairment in craniosynostotic syndromes.

BACKGROUND: To assess the prevalence and causes of visual impairment in patients with craniosynostotic syndromes of Apert, Crouzon, Pfeiffer, Saethre-Chotzen and craniofrontonasal dysplasia. METHODS: The medical records of patients who attended the Craniofacial Clinic at two large paediatric hospitals in Sydney, Australia between 1983 and 2004 were retrospectively reviewed. Presenting visual acuity (VA) was assessed using tests appropriate to age and cognition: 'fix and follow' in infants (<18 months old), Teller card acuity in preverbal children (18 months to less than 3 years old), Kay picture test or Sheridan-Gardiner test in children aged between 3 and less than 6 years and Snellen chart in those aged 6 years or older. Visual impairment was defined as the inability to fix and follow or presenting VA < 6/12 in the better eye. Amblyopia was defined as a two-line difference in VA between both eyes in the absence of an organic eye disease. RESULTS: Sixty-three patients with craniosynostotic syndromes were identified, of whom 55 had VA assessed at the first visit. Of these 55, 19 (35.5%) had bilateral visual impairment and 5 (9.1%) had unilateral visual impairment. Causes of visual impairment include amblyopia (16.7%), ametropia (25%), optic atrophy (16.7%) and exposure keratopathy (4.2%). Risk factors for amblyopia include strabismus (43.3%), astigmatism (> or =1.5 dioptres) (39.5%), hypermetropia (18.4%) and anisometropia (> or =1.5 dioptre difference between both eyes) (15.8%). Six of the 63 patients (9.5%) had papilloedema; those who were followed up showed gradual resolution of papilloedema following timely decompressive surgery. CONCLUSIONS: A high prevalence of visual impairment in patients with craniosynostotic syndromes was found, almost half of them due to potentially correctable causes, including amblyopia and ametropia. Optic atrophy remains an important cause of visual impairment. Further studies are needed to assess the timing and efficacy of intervention for modifiable causes of visual loss in craniosynostotic syndromes.

Adolescent↗
PubMed2005

The effect of relative distance enlargement on visual acuity in the visually impaired.

BACKGROUND: Prescribing magnification is typically based on distance or near visual acuity. This presumes a constant minimum angle of visual resolution with working distance and therefore enlargement of an object moved to a shorter working distance (relative distance enlargement). This study examines this premise in a visually impaired population. METHODS: Distance letter visual acuity was measured prospectively for 380 low vision patients (distance visual acuity between 0.3 and 2.1 logMAR) over the age of 57 years, along with near word visual acuity at an appropriate distance for near lens additions from +4 D to +20 D. Demographic information, the disease causing low vision, contrast sensitivity, visual field and psychological status were also recorded. RESULTS: Distance letter acuity was significantly related to (r = 0.84) but on average 0.1 +/- 0.2 logMAR better (1 +/- 2 lines on a logMAR chart) than near word acuity at 25 cm with a +4 D lens addition. In 39.8 per cent of patients, near word acuity was more than 0.1 logMAR worse than distance letter acuity. In 11.0 per cent of subjects, near visual acuity was more than 0.1 logMAR better than distance letter acuity. The group with near word acuity worse than distance letter acuity also had lower contrast sensitivity. The group with near word acuity better than distance letter acuity was less likely to have age-related macular degeneration. Smaller print size could be read by reducing working distance (achieved by using higher near lens additions) in 86.1 per cent, although not by as much as predicted by geometric progression in 14.5 per cent. DISCUSSION: Although distance letter and near word acuity are highly related, they are on average 1 logMAR line different and this varies significantly between individuals. Near word acuity did not increase linearly with relative distance enlargement in approximately one in seven visually impaired, suggesting that the measurement of visual resolution over a range of working distances will assist appropriate prescribing of magnification aids.

Aged↗
PubMed2006

Mobility performance of low-vision adults using an electronic mobility aid.

Visually impaired people rank obstacle location and identification as two of the most important mobility problems faced. Traditional mobility aids (the long cane) provide information about where an object is located but only within their limited (one metre) range. Although objects are located when traditional aids are used, it is unlikely that they are identified. The Bristol Mobility Aid (BMA) is an electronic travel aid that presents scene images to remaining residual vision in a number of view formats. Previous work has suggested visually impaired observers have better static object recognition using this aid. We investigated the mobility performance of subjects with retinitis pigmentosa using the BMA by determining the percentage preferred walking speed (PPWS), and the number of errors made with three different BMA headset views on an indoor mobility course. We found low-vision subjects had significantly reduced PPWS in two of the three headset views and interestingly, sighted subjects had significantly reduced PPWS when using the BMA in all three views. The numbers of errors made were significantly higher across all vision groups when the BMA was worn. We found that the BMA does not currently increase mobility in the visually impaired. Results are discussed in terms of modifications that could be made to the aid and methodological limitations.

Aged↗
PubMed2005

Availability of accessible publications: designing a methodology to provide reliable estimates for the Right to Read Alliance.

OBJECTIVES: To establish reliable estimates of the proportion of books available in formats accessible to visually impaired people; to recommend a practical method of updating the estimates. METHODS: The project had two stages. Stage one estimated the overall availability of all categories of books. The British National Bibliography (BNB) for 1999-2003 was chosen as the sampling frame. A sample of 2069 titles over the 5 years was selected using a systematic sample design. These titles were then checked for availability against the catalogues of four major producer/suppliers of materials in accessible formats. The second stage involved checking the availability of books in six genres; about 400 titles for each genre were examined. RESULTS: Of the titles selected for the overall estimate, 92 (4.4%) were found to be available in one or more accessible formats. Availability of titles in accessible formats varied greatly between categories. Adult fiction had the highest number of available publications (26.3%), least represented were cookery (1.9%) and gardening (1.8%). CONCLUSIONS: This study provided baseline figures and a methodology for the Right to Read Alliance to monitor their progress in campaigning for more books to be accessible to visually impaired people.

Blindness↗
PubMed1998

Do older drivers with visual and cognitive impairments drive less?

OBJECTIVE: To determine whether older drivers with poorer cognitive and/or visual function drive fewer miles or avoid driving in situations that pose higher crash risks, such as at nighttime, in rush hour traffic, or when weather conditions are bad. DESIGN: A cross-sectional data analysis conducted as part of a larger prospective study. SUBJECTS: A total of 3238 drivers aged 65 and older applying for renewal of their driver's license at one of eight participating North Carolina driver's license offices. MEASUREMENTS: Subjects were administered a battery of brief tests of cognitive and visual function, which included the Trail Making Test Parts A and B, the Short Blessed Orientation-Memory-Concentration test, and measures of high and low contrast visual acuity, contrast sensitivity, and peripheral vision. Participants were also asked to complete a brief driving survey containing questions about the number of miles they drove and whether they avoided driving under certain conditions, such as after dark or on busy, multi-lane roadways. Driver age and gender were covariates in the analyses. RESULTS: Results of multivariate logistic regression models show a clear pattern of reduced driving exposure--lower annual miles and greater avoidance of high-risk driving situations--associated with lower levels of cognitive and visual function. In general, the prevalence odds of reduced driving exposure were higher for the cognitive function variables than for the visual function variables, and higher for males than for females. Men who scored in the lowest quartile of performance on one of the cognitive tests were six to seven times more likely to report driving fewer than 3000 miles a year than were men scoring in the highest quartile, and women with low scores were one-and-one-half to two times more likely to report driving less than 3000 miles than women with higher scores. CONCLUSIONS: While the findings of this study are reassuring, they do not guarantee that all drivers with cognitive and visual impairments are limiting their driving exposure appropriately, and geriatricians and other health professionals should be encouraged to evaluate their patients' cognitive and visual fitness for driving and provide counsel where indicated.

Aged↗
PubMed1997

Visual impairment in Swedish children. III. Diagnoses.

PURPOSE: To gain an overview of the spectrum of diagnoses among Swedish visually impaired children. METHODS: An epidemiological study of all known visually impaired children was made by review of medical records. RESULTS AND CONCLUSION: In all we found 2373 children, 0-19 years of age, with an age-specific prevalence of 10.9/10,000. The two largest diagnostic groups included neuro-ophthalmological and retinal diseases. The most frequent disorders were cerebral visual impairment, non-hereditary optic atrophy, retinal dystrophy (when regarded as a general entity), congenital hypoplasia of the optic nerve and congenital cataract. Nystagmus secondary to brain disorder, albinism, congenital nystagmus, retinopathy of prematurity and high myopia were also found in a considerable number of patients. The leading diagnoses in children with WHO-defined childhood blindness were non-hereditary optic atrophy, cerebral visual impairment and retinopathy of prematurity. A large proportion of the children, especially in the groups with neuro-ophthalmological disorders and malformations of the posterior segment had additional impairments, emphasizing the importance of a multi-disciplinary approach when assessing multi-handicapped children.

Adolescent↗
PubMed2004

Evaluation of visual impairment in Usher syndrome 1b and Usher syndrome 2a.

PURPOSE: To evaluate visual impairment in Usher syndrome 1b (USH1b) and Usher syndrome 2a (USH2a). METHODS: We carried out a retrospective study of 19 USH1b patients and 40 USH2a patients. Cross-sectional regression analyses of the functional acuity score (FAS), functional field score (FFS) and functional vision score (FVS) related to age were performed. Statistical tests relating to regression lines and Student's t-test were used to compare between (sub)groups of patients. Parts of the available individual longitudinal data were used to obtain individual estimates of progressive deterioration and compare these to those obtained with cross-sectional analysis. Results were compared between subgroups of USH2a patients pertaining to combinations of different types of mutations. RESULTS: Cross-sectional analyses revealed significant deterioration of the FAS (0.7% per year), FFS (1.0% per year) and FVS (1.5% per year) with advancing age in both patient groups, without a significant difference between the USH1b and USH2a patients. Individual estimates of the deterioration rates were substantially and significantly higher than the cross-sectional estimates in some USH2a cases, including values of about 5% per year (or even higher) for the FAS (age 35-50 years), 3-4% per year for the FFS and 4-5% per year for the FVS (age > 20 years). There was no difference in functional vision score behaviour detected between subgroups of patients pertaining to different biallelic combinations of specific types of mutations. CONCLUSIONS: The FAS, FFS and FVS deteriorated significantly by 0.7-1.5% per year according to cross-sectional linear regression analysis in both USH1b and USH2a patients. Higher deterioration rates (3-5% per year) in any of these scores were attained, according to longitudinal data collected from individual USH2a patients. Score behaviour was similar across the patient groups and across different biallelic combinations of various types of mutations. However, more elaborate studies, preferably covering longitudinal data, are needed to obtain conclusive evidence.

Adolescent↗
PubMed2006

The key role of electrophysiology in the diagnosis of visually impaired children.

PURPOSE: To describe the outcome of specialized electrophysiology in visually impaired children. METHODS: We carried out a retrospective evaluation of 340 electrophysiological examinations performed in 298 children over a 3-year period (2001-2003), with regard to demographic data, referral pattern, degree of compliance, and diagnostic results. Electrophysiology was performed without sedation or anaesthesia. In electroretinograms, DTL electrodes were used in combination with online selection of responses. Visual evoked potentials testing was performed with seven active occipital electrodes. RESULTS: The mean age of the children was 7 +/- 5 years; 72 (24%) of the children were mentally as well as visually impaired. Main reasons for referral were suspected posterior segment disease, abnormal visual development, unexplained low vision, high myopia, and suspected albinism. Compliance was good in 302/340 (88%), partial in 24/340 (7%), and absent in 14/340 (4%) of the examinations. Of the 326 successful procedures, 215 (66%) showed abnormal results. Tapetoretinal dystrophy (22%), opticopathy (16%), congenital stationary night blindness (13%), and cone dystrophy (11%) were the most frequently established diagnoses. Albinism was confirmed in 14 of 24 suspected patients; additionally, unsuspected misrouting was found in six. In 26 (9%) of the patients, a previously established diagnosis was changed. CONCLUSIONS: In a specialized setting, electrophysiological examinations can be performed successfully in visually impaired children. The results are essential for the final ophthalmological diagnosis and have important consequences for rehabilitation.

Adolescent↗
PubMed2004

Visual acuity and the ability of the visually impaired to read medication instructions.

BACKGROUND/AIMS: Although medical information is often communicated in writing, little attention is given as to whether patients can read it--for example, the miniscule writing on the side of the medication bottles (equivalent to 6/6 reduced Snellen). The authors wished to determine a distance visual acuity threshold, using routine assessments of visual acuity (VA), beyond which patients are unable to read their instructions. METHODS: 180 patients, subgrouped according to the best line of Snellen acuity (from 6/9 to 6/60) achieved in either eye were recruited. Subjects were asked to read the printed manufacturer's instructions on the side of the drops box without magnification. RESULTS: Those subjects with best corrected VA of lower than or equal to 6/24 showed a significantly diminished ability to read the instructions on their eye drops bottles (p<0.001 for each comparison). When this group selected a font size of their choosing, the mode for preferred Arial font sizes were 16 for the 6/24 group, 18 for 6/36, and 22 for 6/60. CONCLUSION: This study documents the inability of patients with visual impairment to read the instructions on their bottle of eye drops. There is evidence of a distance VA threshold effect such that, although the majority of patients with 6/18 VA are able to read their instructions, patients whose VA is worse cannot. This latter group would benefit from a larger font size, a size of Arial 22 being sufficient. We recommend that all printed information for patients with visual acuities between 6/24 and 6/60 be printed in font Arial 22 or equivalent.

Adult↗
PubMed2005

How patients experience progressive loss of visual function: a model of adjustment using qualitative methods.

BACKGROUND: People with retinitis pigmentosa (RP) experience functional and psychological challenges as they adjust to progressive loss of visual function. The authors aimed to understand better the process of adjusting to RP in light of the emotional suffering associated with this process. METHODS: Adults with RP were recruited from the Foundation Fighting Blindness and the Wilmer Eye Institute in Baltimore. Focus groups and semistructured interviews addressed the process of adjusting to RP and were audiotaped and transcribed. The transcripts were analysed qualitatively in order to generate a model of adjustment. RESULTS: A total of 43 individuals participated. It was found that, on diagnosis, people with RP seek to understand its meaning in their lives. Mastering the progressive functional implications associated with RP is contingent upon shifting personal identity from a sighted to a visually impaired person. In this sample, six participants self identified as sighted, 10 self identified as in transition, and 27 self identified as visually impaired. This adjustment process can be understood in terms of a five stage model of behaviour change. CONCLUSIONS: The proposed model presents one way to understand the process of adjusting to RP and could assist ophthalmologists in meeting their moral obligation to lessen patients' suffering, which arises in the course of their adjustment to progressive loss of visual function.

Adaptation, Psychological↗
PubMed2005

The development of the Indian vision function questionnaire: questionnaire content.

AIM: To elicit problem statements describing the consequences of vision impairment as a first step towards the development of a vision related quality of life instrument for use in India METHODS: 46 focus groups were conducted in three regions of India. Separate focus groups were held for men and women and according to disease categories: cataract (24), glaucoma (six), diabetic retinopathy or macular degeneration (10), and "mixed low vision" (six). Facilitators followed a topic guide and sessions were audio taped and transcribed. Problem statements were extracted and coded and summarised into major problem domain areas. RESULTS: Nearly 5000 problem statements, an average of 15 statements per participant, were consolidated into 18 broad domain areas. The most important problem areas accounting for over 50% of all statements were ambulation, household or occupational activities, vision symptoms, and people recognition. A further quarter of statements related to difficulties with eating and drinking, psychological concerns, self care, reading, and watching television. Problem statements were similar across the disease groups, although rankings varied. CONCLUSIONS: The functional and psychological impacts described by visually impaired participants in India are similar to those reported in other population settings although the context and impact of problems vary.

Activities of Daily Living↗