Causes of severe visual impairment and blindness in schools for visually handicapped children in Iran.
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AIMS: This survey was conducted on children in schools for the blind in Tehran (from 2002 to 2003) to determine the causes of severe visual impairment and blindness and to identify preventable and treatable conditions. METHODS: The study was performed on 362 students at different grades in three schools for the blind. Patient sex, age, family history of blindness or low vision, visual acuity, causes of blindness, and treatable and preventable conditions were studied. RESULTS: Of the 362 cases, 210 (58%) were boys and 152 (42%) were girls. Mean age was 13.5 (SD 4) years. Severe visual loss was seen in 80.9%. Retinal diseases were the most common cause for low vision (51%); cataract, optic nerve atrophy, corneal and anterior segment diseases, glaucoma, anophthalmia, and globe malformations were other major causes of blindness. Treatable aetiologies and positive family history of blindness were seen in 25.7% and 36% of the patients, respectively. The incidence of preventable diseases, excluding familial disorders, was low. CONCLUSION: In addition to the prevention and treatment of some conditions, premarital genetic counselling and family planning control in families with inherited diseases could decrease the number of blind children in the future in Iran. (+info)
Prevalence and burden of self-reported blindness and low vision for individuals living in institutions: a nationwide survey.
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BACKGROUND: The prevalence of self-reported low vision (LV) and blindness, and their associated disabilities, handicaps and socio-economic consequences for individuals living in institutions are poorly documented. METHODS: 2,075 institutions were selected at random and eight individuals were picked at random from the list of residents. Three groups of individuals were defined: blind, LV, and a control group (CG). These were compared after adjustment for age and co-morbidities. Of the 15,403 individuals, 14,603 interviews (94.9%) were completed. RESULTS: The prevalence of blindness was 1.6% and the LV 13.4%. Blind individuals needed assistance more often (OR: 2.65 to 11.35) than CG members while the assistance required by LV individuals was similar to that for the CG. Blind individuals required institution adaptation (building and furniture changes) more often than the CG. Blind (57.9%) and LV individuals (35.4%) were more often registered for social allowances. Monthly social allowances were EUR 86 higher for blind than LV individuals. Monthly family incomes were found to be similar between the three groups (from EUR 782 to 797). Social and demographic data, institution description, income, handicaps, disabilities, social allowances and details of daily activities were collected interviews. CONCLUSION: The results demonstrate the impact of self-reported blindness and LV on daily life for patients living in institutions. (+info)
Postoperative intensity-modulated radiotherapy in sinonasal carcinoma: clinical results in 39 patients.
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BACKGROUND: Carcinoma of the paranasal sinuses is rare. Standard therapeutic modalities consist of surgery and radiotherapy (RT). Because of the often advanced stage and the vicinity of optic structures, RT-induced ocular toxicity is a feared side effect of conventional RT. Intensity-modulated radiotherapy (IMRT) is a relatively new technique, which is implemented with the hypothesis that, compared with conventional RT, it would result in a lower rate of ocular toxicity for an equal local control (LC). METHODS: Between 1998 and 2003, 39 consecutive patients received postoperative irradiation by means of IMRT for an adenocarcinoma (n = 31) or squamous cell carcinoma (n = 8) of the paranasal sinuses (n = 36) or nasal cavity (n = 3). T-classification was T2 in 41%, T3 in 15%, T4a in 23%, and T4b in 21% of patients. Invasion through the cribriform plate was seen in 11 patients. Orbital invasion was present in 36% of patients. The median delivered dose was 70 gray (Gy) (range, 60-70 Gy). The authors compared the overall survival (OS) and LC of the patients with a historic cohort (HC) (n = 30), treated with conventional or 3-dimensional conformal RT. RESULTS: The median follow-up was 31 months. The actuarial OS rates were 68% at 2 years and 59% at 4 years. The actuarial LC rates were 73% at 2 years and 68% at 4 years. Invasion through the cribriform plate was a significant prognostic factor for LC and OS, with a median time to local disease recurrence of 7 months if present, and a 2-year LC rate of 90% if not present. In the comparison between the IMRT and HC groups, no significant differences were found for LC and OS. Acute toxicity was mild. Two patients developed decreased vision after RT. No RT-induced blindness was observed. CONCLUSIONS: Postoperative IMRT for sinonasal carcinoma resulted in good LC, with a low acute toxicity and no RT-induced blindness. (+info)
Unregistered visual impairment: is registration a failing system?
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BACKGROUND/AIMS: To assess the current level of under-registration of blindness and partial sight among patients attending a large teaching hospital, and to determine any risk factors for under-registration. METHODS: Medical records of all patients attending general ophthalmology outpatient clinics over a 3 month period were included in a retrospective analysis of registration rates; questionnaire survey assessing the level of knowledge of registration practices among 35 ophthalmologists working in the West Midlands. RESULTS: 146/2161 (7%) patients were eligible for blind or partial sight registration, or were in possession of a completed BD8 form. Of these 146 patients, 65 (45%) were unregistered with 18 fulfilling the criteria for blind and 47 for partially sight. In addition, 32/81 (40%) registered patients appeared to have been inappropriately registered. Partially sighted patients were more likely to be unregistered than blind patients (OR 2.31, 95% CI 1.15 to 4.63, p = 0187), and patients from ethnic minorities were more than three times more likely to be unregistered than white patients (OR 3.23, 95% CI 1.56 to 6.65, p = 0.0015). A patient with a treatable condition was more likely to be unregistered than a patient with an untreatable condition (OR 4.87, 95% CI 2.10 to 11.33, p = 0.0002). The overall level of knowledge of registration practices among doctors was found to be low and there was no indication of increasing knowledge with increasing experience. CONCLUSIONS: There has been little improvement in registration rates of visually impaired patients over the past decade. Ophthalmologists lack the necessary knowledge to cater for visually impaired patients' needs. (+info)
Serifs and font legibility.
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Using lower-case fonts varying only in serif size (0%, 5%, and 10% cap height), we assessed legibility using size thresholds and reading speed. Five percentage serif fonts were slightly more legible than sans serif, but the average inter-letter spacing increase that serifs themselves impose, predicts greater enhancement than we observed. RSVP and continuous reading speeds showed no effect of serifs. When text is small or distant, serifs may, then, produce a tiny legibility increase due to the concomitant increase in spacing. However, our data exhibited no difference in legibility between typefaces that differ only in the presence or absence of serifs. (+info)
Social and visual function in nystagmus.
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AIM: To investigate the influence of nystagmus on visual and social function and determine if parents are able to assess visual and social function in children with nystagmus. METHOD: A postal questionnaire comprising 14 questions related to visual function (VF-14) and questions pertaining to social function were sent to all 1013 members of the Nystagmus Network-a UK based organisation for nystagmus sufferers and their families. Visual and social function scores were compared by regression analysis. RESULTS: 180 adult, 233 parent, and 124 child questionnaires were returned. Idiopathic nystagmus was the most common cause. In adults the mean VF-14 score indicated very low visual function, in the same range as patients assessed in low vision services. Children's visual function scored better than adults, between scores of patients with age related macular disease and corneal grafts. There was a strong correlation between perceived visual and social function for adults (p<0.001) and parental assessment of their children (p<0.001), but not between child self assessment of visual and social function. There was strong correlation between parental and child assessment of visual and social function (p<0.001, p<0.001) CONCLUSION: Questionnaires indicated that nystagmus is associated with very low visual function. There is a strong correlation between visual and social impairment. The authors have shown for the first time in an ophthalmic disease that parents are able to estimate the impact of nystagmus on their child both in terms of visual and social functioning, although they underestimate the impact of nystagmus on emotional aspects of wellbeing. (+info)
Comparison of low-vision reading with spectacle-mounted magnifiers.
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Reading is the most common goal among persons with age-related macular degeneration and other retinal diseases that lead to macular loss, as well as the functional task most affected by the resulting central scotomas. This project determined whether reading ability is different when persons with macular loss read with a new hybrid-diffractive spectacle magnifier versus a refractive-aspheric spectacle magnifier and an aplanatic spectacle magnifier. After subjects completed a low-vision examination, we assigned them to groups that compared different types of spectacle magnifiers and assessed their reading acuity, speed, critical print size (print size large enough to provide a subject's best fluent reading), accuracy, and comprehension. Subjects completed visual analog scales to indicate their perceptions of satisfaction with reading, comfort with reading, and cosmesis (comfort with allowing others to see them read) and were asked which of the compared spectacle magnifiers they preferred for prescription. We subjected the data to paired t-tests to ascertain whether differences existed in subjects' reading ability and perceptions between the types of reading devices. Subjects' reading comprehension, perception of satisfaction, and perception of cosmesis were significantly better with the hybrid-diffractive lens than with the refractive-aspheric lens. Although subjects' critical print size was significantly better with the aplanatic lens than with the hybrid-diffractive lens, functional reading ability was not significantly different. More subjects preferred the hybrid-diffractive lenses for prescription. The hybrid-diffractive spectacle magnifiers are an important addition to the optical-device armamentarium for reading with low vision. (+info)
Improving nighttime mobility in persons with night blindness caused by retinitis pigmentosa: A comparison of two low-vision mobility devices.
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This study compared the effectiveness of the ITT Night Vision Viewer with the Wide Angle Mobility Lamp (WAML) as low-vision mobility devices for people experiencing night blindness due to retinitis pigmentosa (RP). Both engineering bench testing and functional evaluations were used in the assessments. Engineering evaluations were conducted for (1) consistency of the manufacturer's specifications, (2) ergonomic characteristics, (3) modifications of devices, and (4) pedestrian safety issues. Twenty-seven patients with RP conducted rehabilitation evaluations with each device that included both clinical and functional tests. Both devices improved nighttime travel for people with night blindness as compared with nighttime travel with no device. Overall, the WAML provided better travel efficiency-equivalent to that measured in daytime. Recommendations have been developed on ergonomic factors for both devices. Although some participants preferred the ITT Night Vision Viewer, overall most participants performed better with the WAML. (+info)