Helping Blind and Partially Sighted People to Read: the Effectiveness of Low Vision Aids
Tom H Margrain
Aims: To substantiate the claim that low vision aids reduce the degree of disability associated with visual impairment.
Methods: An observational study of vision, ocular pathology, age, sex, and reading ability in new referrals to a low vision clinic. Reading ability was assessed both with the patients’ own spectacles and with an appropriate low vision aid.
Results: The reading performance and biographical characteristics of new referrals to a low vision clinic were recorded. Data were collected for 168 people over a 6 month period. Upon arrival at the clinic the mean functional visual acuity equated to 6/36 and 77% of patients were unable to read newsprint (N8). After a low vision assessment and provision of a suitable low vision aid, 88% of new patients were able to read N8 or smaller text.
Conclusions: The degree of visual impairment observed in new referrals to a low vision clinic is sufficient to prevent the majority from performing many daily tasks. Low vision aids are an effective means of providing visual rehabilitation, helping almost nine out of 10 patients with impaired vision to read.
Published courtesy of: Br J Ophthalmol 2000; 84: 919-921
Planning Low Vision Services in India A Population-based Perspective
Rakhi Dandona PhD, Lalit Dandona MD MPH, Marmamula Srinivas BA, Pyda Giridhar PhD, Rishita Nutheti MSc, Gullapalli N Rao MD
Objective: To access the prevalence and causes of low vision in a population in southern India for planning low vision services.
Design: Population-based, cross-sectional study.
Participants: A total of 10,293 persons of all ages from 94 clusters representative of the population of the Indian state of Andhra Pradesh.
Methods: The participants underwent a detailed eye examination, including measurement of visual acuity with logarithm of the minimum angle of resolution charts, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated using predefined criteria.
Main Outcome Measures: Low vision was defined as permanent visual impairment that was not correctable with refractive error correction or surgical intervention. The participants with best-corrected distance visual acuity <6/18 to perception of light or central visual field <10° because of an untreatable cause in both eyes were considered as having low vision. Results: Low vision was present in 144 participants, an age, gender, and urban-rural distribution adjusted prevalence of 1.05% (95% confidence interval, 0.82%-1.28%). The most frequent causes of low vision included retinal diseases (35.2%), amblyopia (25.7%), optic atrophy (14.3%), glaucoma (11.4%), and corneal diseases (8.6%). Multivariate analysis showed that the prevalence of low vision was significantly higher with increasing age, and there was a trend for higher prevalence with decreasing socioeconomic status. Extrapolating these data to the estimated 1014 million population of India in the year 2000, 10.6 (95% confidence interval, 8.4- 12.8) million people would have low vision. Conclusions: These data imply that there is a significant burden of low vision in this population, suggesting the need for low vision services. Published courtesy of: Ophthalmology 2002; 109: 1871-1878
Survey of Visual Impairment in an Indian Tertiary Eye Hospital
Peter Herse PhD FAAO, Vijaya K Gothwal BOpt
A retrospective survey of 4,122 consecutive patient records was performed in a tertiary care eye hospital in Hyderabad, India. Data collected included age, gender, visual acuity after completion of treatment and diagnosis. 62.8% of the patients were male. After completion of treatment, 10.8% had low vision (best corrected visual acuity <6/18 to 3/60 in the better eye) and 2.6% were blind (best corrected visual acuity <3/60 in the better eye). Most cases of low vision were found in the 50 to 70 year age group (42.9%). The most common visual acuity range after treatment amongst patients with vision loss was <6/18 to 6/60 (71%). The 4 main causes of low vision were cataract (21.4% of low vision group), glaucoma (14.0%), diabetic retinopathy (13.0%), and retinitis pigmentosa (10.7%). The 4 main causes of blindness were glaucoma (16.3% of blind group), diabetic retinopathy (13.2%), corneal opacities (11.6%) and retinitis pigmentosa (11.6%). It is suggested that patients with low vision at the conclusion of treatment be referred to a vision rehabilitation centre. Referral should be made in cases with a best corrected visual acuity <6/18 to 3/60 or with visual field loss to within 15° of fixation. Patients aged under 50 years of age are expected to achieve maximal rehabilitation success. Motivation and vocational requirements should be assessed in older or more complex cases before referral. The data of this study show that about 10% of patients seen at a tertiary care eye hospital in India could benefit from low vision rehabilitation. Published courtesy of: Indian J Ophthalmol 1997; 45: 189-193
Aetiology of Suppurative Corneal Ulcers in Ghana and South India, and Epidemiology of Fungal Keratitis
A K Leck, P A Thomas, M Hagan J Kaliamurthy, E Ackuaku, M John, M J Newman, F S Codjoe, J A Opintan C M Kalavathy, V Essuman C A N Jesudasan, G J Johnson
Background: A multicentre study was carried out in Ghana and southern India to determine the aetiology of suppurative keratitis in two regions located at similar tropical latitudes. Studies of fungal keratitis from the literature were reviewed.
Methods: Patients presenting at rural and urban eye units with suspected microbial keratitis were recruited to the study. Corneal ulceration was defined as loss of corneal epithelium with clinical evidence of infection with or without hypopyon. Microscopy and culture were performed on all corneal specimens obtained.
Results: 1090 patients were recruited with suspected microbial keratitis between June 1999 and May 2001. Overall the principal causative micro-organisms in both regions were filamentous fungi (42%): Fusarium species and Aspergillus species were the commonest fungal isolates. Pseudomonas species were most frequently isolated from cases of bacterial keratitis in Ghana but in India the commonest bacterial isolates were streptococci.
Conclusion: Infections of the cornea due to filamentous fungi are a frequent cause of corneal damage in developing countries in the tropics and are difficult to treat. Microscopy is an essential tool in the diagnosis of these infections. A knowledge of the ‘local’ aetiology within a region is of value in the management of suppurative keratitis in the event that microscopy cannot be performed.
Published courtesy of: Br J Ophthalmol 2002; 86: 1211-1215
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