Assessing the diagnostic validity of a blind register

Background: To validate the accuracy of clinical ophthalmic information held on the West Australian blind register. Design: Community‐based cross‐sectional study. Participants: Legally blind or severely vision‐impaired people were selected randomly from the Association for the Blind of Western Australia register. Methods: Individuals were reviewed by one of two consultant ophthalmologists. Main Outcome Measures: The positive predictive value (ppv), sensitivity and specificity for legal blindness status and diagnostic causes of vision loss were calculated using data extracted from the Association for the Blind of Western Australia blind register. Results: 273 blind or near blind people were reviewed from the register total of 4271 individuals. There were more women (57%) than men, median age 81 years. For legal blindness status the ppv was 0.88 (95% confidence interval [CI] 0.82–0.92), sensitivity 0.75 (95% CI 0.74–0.84) and specificity 0.6 (95% CI 0.46–0.73). The ppv for the diagnostic causes of blindness were: age‐related macular degeneration = 0.95 (95% CI 0.91–0.97), retinitis pigmentosa ppv = 1 (95% CI 0.81–1.0), diabetic retinopathy ppv = 0.9 (95% CI 0.57–0.99), optic neuropathies ppv = 0.77 (95% CI 0.51–0.92) and glaucoma ppv = 0.87 (95% CI 0.7–0.96). Forty individuals (15%) had treatable conditions contributing to their vision loss. Conclusions: The blind register diagnoses and legal blindness status are of high accuracy. This information allows useful linkages to other databases for studies of blindness interactions. A regular updating mechanism would improve the future accuracy of this valuable regional asset. The presence of untreated cataract suggests that regular follow up and appropriate treatment may help optimize vision in blind patients.     

Do gender inequities exist in cataract surgical coverage? Meta‐analysis in Latin America

Background: To determine if gender inequities exist in Latin America in regard to cataract surgery. Design: Meta‐analysis. Participants: Total of 38 992 subjects participating in epidemiological surveys; summary measures were used (not patient‐level data). Methods: A literature search and knowledge of rapid assessment of cataract surgical services/rapid assessment of avoidable blindness studies carried out in Latin America found 11 studies with complete cataract surgical coverage (CSC) data. Using summary original study data, a meta‐analysis (random effects model) was conducted to analyse the differences in CSC between males and females. Results were adjusted for design effect. Main Outcome Measures: Odds ratio (OR) of receiving cataract surgery comparing women with men. Results: CSC with a visual acuity (VA) <3/60 on an eye basis showed a non‐statistically significant OR of 1.01 (95% confidence intervals [CI]: 0.86–1.18) for women receiving cataract surgery in comparison with men. For VA < 6/18, a non‐statistically significant OR of 0.94 (95% CI: 0.83–1.07) was obtained for women receiving cataract surgery. On a person basis at a VA of <3/60 and <6/18, non‐statistically significant ORs of 1.12 (95% CI: 0.78–1.63) and 0.94 (95% CI: 0.77–1.15) were obtained for women receiving cataract surgery, respectively. Statistical heterogeneity was 0% (I² statistic), except for results at a VA of <3/60 on a person basis (I² = 30%). Conclusions: In the Latin American countries in which CSC was assessed, gender does not appear to be a significant factor in receiving cataract surgery. However, more data are required to confirm these results.     

Changes in blindness prevalence over 16 years in Malawi: reduced prevalence but increased numbers of blind

BACKGROUND/AIMS: In the coming two decades significant increases in the burden of blindness are anticipated unless concerted efforts are made to improve eye care in developing countries. Evidence of changing prevalence rates or numbers of blind people are few. The change in blindness prevalence and the number of blind people in an adult population of Malawi was measured over a 16 year period. METHODS: In 1999 a population based survey of blindness in adults (age 50+) was conducted in Chikwawa district of Malawi. Visual acuity and cause of vision loss were recorded for each eye independently. Blindness was defined as presenting better eye vision of <6/60. Findings from a 1983 survey of blindness in the same district (using similar methods) were re-analysed to be comparable with the survey conducted in 1999. RESULTS: Among 1630 enumerated adults 89% were examined. The age adjusted prevalence of blindness in the adult population was 5.4% and more common in women than men. In each age group the prevalence of blindness was lower in 1999 than in 1983; the overall reduction in blindness was 31%. During this period the 50+ population in Malawi increased almost twofold. Extrapolating the Chikwawa district data to the Malawi population reveals that the number of blind people has increased by 24%; the increase is primarily because of the large increase in the size of the most elderly group, aged 70 and above. CONCLUSION: The majority of blind people in Chikwawa (1983 and 1999) are in the age group 70 and over. This group has had the largest proportional increase in population size in this time. Services in this population have improved in the intervening 16 years and yet there was still an increase in the number of blind people. There was little change in excess blindness in women, suggesting that the same barriers that prevented utilisation of services in 1983 probably persist in 1999. Efforts to reach the most elderly and to reach women are needed to lead to a reduction in blind people in settings such as rural Malawi.     

Rapid assessment of cataract at pension pay points in South Africa

AIM: To test a method for the rapid assessment of cataract blindness in South Africa. DESIGN: Randomised cluster-based cross-sectional survey (20 clusters of 50 each). SETTING: Pension pay points in Moretele district, North West Province, South Africa. SUBJECTS: Female pensioners aged >or=60 years, and male pensioners aged >or=65 years. OUTCOME MEASURES: (1) Prevalence of cataract requiring surgery; (2) prevalence of blindness due to cataract; (3) cataract surgical coverage; (4) cataract surgery outcome; and (5) barriers to cataract surgery. RESULTS: 1000 pensioners were screened (681 women and 319 men). 17.2% of pensioners had operable cataract (visual acuity <6/60); 95% CI -3.4% to 3.4%); 15.6% of pensioners were blind due to cataract (95% CI -3.1% to 3.4%); and 5.6% of pensioners had had previous cataract surgery, 55.4% with intraocular lens implant and 44.6% without intraocular lens implant. The cataract surgical coverage was 24.6%. 80% of people who had had surgery were satisfied with the result, but 26.8% had a poor outcome according to the World Health Organization criteria. The main barrier to uptake of surgery was a lack of awareness of the availability of the surgery. CONCLUSIONS: Rapid assessment of cataract at pension pay points is a useful and effective tool for our district Vision 2020 programmes in South Africa. Steps need to be taken to raise awareness of the availability of cataract surgery among indigent pensioners, and to improve the quality of visual outcome after surgery by ensuring routine monitoring of postoperative visual acuity.     

Cataract blindness in Paraguay – results of a national survey

PURPOSE To estimate the burden of visual loss and blindness due to cataract in people aged 50 years and over in Paraguay. METHODS Forty clusters of 60 persons each who were 50 years and older (2400 eligible persons) were selected by systematic random sampling from the entire population of Paraguay.A total of 2136 persons were examined (89% coverage). RESULTS For the population 50 years and over, the age- and gender- adjusted prevalence of bilateral blindness (VA &lt; 3/60 with available correction) was 3.14% (95% CI: 2.2–4.4). The adjusted prevalence of bilateral cataract blindness (VA &lt; 3/60) was 2.01% (95% CI: 1.3–3.0), making cataract the major cause of bilateral blindness in this age group (64%). The adjusted prevalence of bilateral severe visual impairment (VA &lt; 6/60 with available correction) was 5.17% (95% CI: 3.9–6.7) and the adjusted prevalence of severe visual impairment due to bilateral cataract (VA &lt; 6/60) was 3.09% (95% CI: 2.2–4.3). The cataract surgical coverage (persons) was 44% for bilaterally blind persons with VA &lt; 3/60; 36% for persons with bilateral VA &lt; 6/60; and 28% for any eye with VA &lt; 6/60 due to cataract. With IOL implantation, 77% of the operated eyes could see 6/18, against 46% of the non-IOLs (p &lt; 0.005), a significant better outcome. CONCLUSIONS There is a need to increase the cataract surgical coverage in Paraguay. The number of eye surgeons is adequate but the accessibility of cataract surgical services in rural areas and the affordability of surgery to large sections of society are major constraints.     

Intracapsular cataract extraction: Experience of a general surgeon in Niger, West Africa

Background: Cataract is the major cause of blindness in the world and affects an estimated 20 million persons globally. In Africa, there is an incidence of half a million new cases of cataract blindness annually, with a backlog of 3 million persons requiring sight-restoring surgery. The burden of this form of curable blindness resides mainly in less developed nations, which typically have limited numbers of ophthalmologists and medical resources. The experience and results of a general surgeon working in rural West Africa, without prior ophthalmic skills but with limited training in the field, are reported. Methods: Data on all consecutive planned intracapsular cataract extractions performed between January 1994 and July 1995 inclusive were collected prospectively and the visual outcome as well as surgical complications were analysed. Results: A total of 243 planned intracapsular cataract extractions were performed. Data were incomplete or missing in five cases leaving 238 for analysis. All the patients were blind pre-operatively, with visual acuities of 3/60 or less. Functional vision (6/60 or better) was restored in 95% of all cases. Conclusions: General surgeons can be satisfactorily trained in the art of intracapsular cataract extractions, with good visual outcomes. This is very useful in the setting of undeveloped countries where there are severe limitations of resources, and the recruitment of trained general surgeons will help reduce the burden of curable blindness in these regions.     

Blindness and eye diseases in Tibet: findings from a randomised, population based survey

BACKGROUND: Public health officials of the Tibet Autonomous Region (TAR) of China requested a survey of blindness, eye diseases, and eye care service utilisation to assist the development of a 10 year blindness prevention and treatment plan. The objective of the survey was to determine the prevalence of blindness and visual impairment, as well as cataract surgical coverage and surgical outcome in the TAR. METHODS: The Tibet Eye Care Assessment was a cross sectional prevalence study of three of the seven prefectures (provinces) of the TAR (Lhoka, Nakchu, and Lingzhr) selected to represent its three main environmental regions. The survey sample was selected using a random multistage cluster method. Two teams conducted the survey in a standardised fashion in each prefecture, Lhoka during May and Nakchu during June 1999, and Lingzhr during May 2000. Visual acuity, cause of vision loss, trachoma, and vitamin A deficiency were included in the clinical examination. RESULTS: Among the 15,900 people enumerated, 12,644 were examined for an overall response rate of 79.6%. The crude prevalence of blindness (presenting better eye visual acuity of less than 6/60) was 2.3%; age and sex adjusted blindness prevalence was 1.4% (95% CI 1.3 to 1.5). Visual impairment (better eye presenting visual acuity of 6/24 to 6/60) was found in 10.9% (95% CI 10.5 to 11.2) of the population (age and sex adjusted). Cataract was the primary cause of blindness (50.7%), followed by macular degeneration (12.7%) and corneal opacity (9.7%). CONCLUSION: Blindness is a serious public health problem in Tibet, with prevalence higher than in similar studies in eastern China. As elsewhere in the world, women have an excess burden of blindness compared to men. About 75% of blindness in Tibet can be either prevented or treated. Eye care planning for Tibet must focus on cataract, particularly among women.     

Use of Cataract Services in Eastern Africa—A Study from Tanzania

Purpose: To establish the proportion of patients who are blind or have low vision prior to undergoing cataract surgery at tertiary referral centers in Tanzania. To assess which patient groups presenting for cataract surgery are more likely to be blind or visually impaired. Methods: Using pre-existing computerized audit systems we gathered data on pre-operative visual status, age, gender and presentation mode (walk-in or outreach) for 3765 patients undergoing 4258 cataract operations at 2 hospitals in Tanzania. Visual status was defined based on vision in the better eye. Results: 32% of operations were performed on blind patients, 37% on patients with low vision and 31% on normally sighted patients. Predictors of blindness at presentation were: female sex (OR 1.15; 95% CI 1.00–1.32); referral from a rural outreach program (OR 1.75; 95% CI 1.51–2.02) and older age (OR 1.02; 95% CI 1.01–1.02). Conclusions: It is not only the blind who present to cataract services in Tanzania. The demand for surgery amongst patients who or are normally sighted represents a positive move towards prevention, and not only cure of cataract blindness in Tanzania. However, it also highlights the need to target those left blind from cataract in order to deliver services to those most in need. Cataract programs targeting patients in rural areas and older patients are likely to increase the number of blind patients benefiting from cataract services.     

Prevalence of blindness and visual impairment in Pakistan: the Pakistan National Blindness and Visual Impairment Survey

PURPOSE: To determine the prevalence of blindness and visual impairment in adults aged 30 years and older in Pakistan and to assess socio-demographic risk factors. METHODS: Multistage, stratified (rural/urban), cluster random sampling, with probability proportional-to-size procedures, was used to select a nationally representative, cross-sectional sample of adults 30 years of age or older. Each subject was interviewed; had visual acuity measured (logMAR; logarithm of the minimum angle of resolution); and underwent autorefraction, biometry, and fundus-optic disc examination. Those with less than 6/12 acuity in either eye underwent a detailed ophthalmic examination, including corrected distance visual acuity measurement and dilated ophthalmoscopy. RESULTS: A nationally representative sample of 16,507 adults (95.5% of those enumerated) was examined. The age- and gender-standardized prevalence of blindness was 2.7% (95% confidence interval [CI], 2.4%-2.9%). It has been estimated that there are 1,140,000 (962,000-1,330,000) blind adults in Pakistan (2003 statistics). Blindness prevalence varied throughout the country, being highest in the provinces of Punjab and Baluchistan and lowest in the North West Frontier Province. Rural areas had a higher prevalence of blindness than did urban areas (3.8% vs. 2.5%, P < 0.001). Increasing age and being female were significantly associated with presenting visual acuity of <6/60 (odds ratio [OR], 2.5; 95% CI, 2.3-2.7 and 1.3; 95% CI, 1.1-1.5, respectively). Educational status was also associated with presenting visual acuity of <6/60. Subjects who had attended primary school were 60% (P < 0.001) less likely to have acuity of <6/60 than were subjects who had never been to school. CONCLUSIONS: This comprehensive survey provides reliable estimates of the prevalence of visual impairment and blindness in Pakistan. A significant excess of visual impairment was found among the elderly and the uneducated. After adjustment for age differences, women were found to have a significant excess of severe visual impairment and blindness. Regional variations in the prevalence of blindness were also identified.     

Blindness and Low Vision in Cape Verde Islands: Results of a National Eye Survey

Aims: Prior to establishing a national prevention of blindness program a population based survey was conducted in Cape Verde Islands in1998. The objectives of the survey were to estimate the overall and age-specific prevalence of blindness and low vision, to identify the main disorders causing blindness and low vision, and to estimate the population need for basic eye care services. Methods: A two-level cluster random sampling procedure was used, selecting 30 clusters from the nine inhabited islands and 3,803 persons of all ages were included in the sample. Results: 3,374 persons were examined (coverage 88.7%). The prevalence of bilateral blindness (visual acuity in the better eye less than 3/60) was 0.8% (95% confidence interval [CI] 0.5–1.1), of bilateral low vision (6/18 to 3/60 in the better eye) 1.7% (95% CI: 1.3–2.2) and of monocular blindness 1.5% (95% CI: 1.2–2.0). The major causes of blindness were age related cataract and glaucoma (57.7% and 15.4%, respectively, of blind people recruited). The major causes of bilateral low vision were cataract, refractive errors, and macular disorders (46.2%, 26.8%, and 8.9%, respectively, of persons with low vision). Nontrachomatous corneal opacities accounted for 7.7% of bilateral and for 11.5% of monocular blindness. Vascular retinopathy was responsible for 7.7% of bilateral and for 9.6% of monocular blindness. Trachoma is not a public health problem as only 2.3% of children less than 10 years of age were suffering from active trachoma. Palpebral or limbal vernal conjunctivitis were encountered in 4.5% of persons under 25. Conclusion: More than half of the visual impairments are treatable by provision of cataract surgery and cataract has been indicated as a priority target in the recently designed National Blindness Program of the Cape Verde Republic. Pathologic conditions such as diabetes are emerging as serious burden for ageing populations and account for most of the retinal vascular disease.     

Factors associated with lifetime risk of open‐angle glaucoma blindness

Purpose: To investigate factors associated with bilateral glaucoma blindness, particularly factors available at the time of diagnosis. Methods: Retrospective chart review of all patients with primary open‐angle glaucoma (POAG) or pseudoexfoliative glaucoma (PEXG) followed at the Department of Ophthalmology or Low Vision Center of Skåne University Hospital, Malmö, Sweden, who died between January 2006 and June 2010. Disease stage at diagnosis was defined by a simplified version of Mills’ glaucoma staging system using perimetric mean deviation (MD) to define six stages of severity. Blindness was defined according to WHO criteria. We used logistic regression analysis to examine the association between risk factors and glaucoma blindness. Results: Four hundred and 23 patients were included; 60% POAG and 40% PEXG. Sixty‐four patients (15%) became blind from glaucoma. Blind patients had significantly longer mean duration with diagnosed disease than patients who did not go blind (14.8 years ± 5.8 versus 10.6 years ± 6.5, p < 0.001). The risk of blindness increased with higher intraocular pressure (IOP) (OR 1.08, 95% CI 1.03–1.13) and with each stage of more advanced field loss at time of diagnosis (OR 1.80 95% CI 1.34–2.41). Older age at death was also associated with an increased risk of blindness (OR 1.09 95% CI 1.03–1.14), while age at diagnosis was unimportant. PEXG was not an independent risk factor for blindness. Conclusions: Higher IOP and worse visual field status at baseline were important risk factors, as was older age at death.     

Prevalence and causes of blindness and low vision in a rural setting in Pakistan

PURPOSE: To determine the prevalence and causes of blindness and visual impairment in people 40 years of age and older in Budni, Peshawar, Pakistan. METHODS: A population-based cross-sectional study was carried out involving 1,106 men and women 40 years of age and older in a rural area in Pakistan's North West Frontier Province (NWFP). All subjects with a presenting visual acuity < 6/18 in either eye were referred to a centralized clinic for a standardized eye examination that included refraction and dilated fundal examination. The main outcome was blindness (presenting visual acuity < 3/60 in the better eye) and low vision (presenting VA < 6/18-3/60 in the better eye). RESULTS: Of 1,106 people examined, 21 (1.9%; 95% CI: 1.1-2.7%) were blind, while another 27 (2.4%) and 62 (5.5%) subjects had severe visual impairment (< 6/60-3/60) and visual impairment (< 6/18-6/60), respectively. Women, as compared to men, had a higher prevalence of visual impairment and severe visual impairment; but they had a lower prevalence of blindness (1.6 vs. 2.2%); however, the difference was not statistically significant (0.6%; 95% CI: -0.9-2.1%). Similarly farmers had the highest prevalence of blindness. The leading cause of blindness and low vision was cataract, which accounted for 14 of 21 (66.6%) cases of blindness and 49 of 89 (55.5%) cases of low vision. The second leading cause of blindness was uncorrected aphakia. CONCLUSION: Much of the blindness was due to unoperated cataract and uncorrected aphakia. Thus, there is an urgent need to develop ways in which cataract surgical output could be increased, and glasses provided to those who need them.     

Ocular trauma in an urban population in southern India: the Andhra Pradesh Eye Disease Study

Purpose : To assess the cumulative prevalence of ocular trauma and presence of vision loss due to ocular trauma in an urban population in southern India. Methods : As part of the population‐based Andhra Pradesh Eye Disease Study, 2522 people of all ages from 24 clusters representative of the population of Hyderabad city in southern India, underwent a detailed interview and standardized dilated ocular evaluation. An eye was considered to be blind due to trauma if best corrected distance visual acuity was worse than 6/60 due to trauma. Results : One hundred and thirteen subjects gave a history of ocular trauma and another two had evidence of ocular trauma by examination, a combined age–sex‐adjusted rate of 3.97% (95% CI 2.52–5.42%). Blindness in one eye due to trauma was present in 17 subjects, and in both eyes in one subject, a combined age–sex‐adjusted prevalence of 0.60% (95% CI 0.23–1.04%). Visual acuity in all the blind eyes except one was worse than 3/60. With multiple logistic regression, the odds of blindness in at least one eye due to trauma were highest for current age range of 30–39 years (odds ratio 6.33, 95% CI 1.69–23.77 compared with a current age of less than 30 years), were significantly higher for lower socioeconomic status (3.74, 95% CI 1.18–11.84), and were higher for males (2.48, 95% CI 0.91–6.82) though this did not reach statistical significance. Trauma resulting in blindness had occurred by the age of 15 years in 55% of subjects, and before the age of 40 years in 92.1% of subjects; this had occurred most commonly while playing (53.6% of the cases). With multiple logistic regression, the odds ratios for any ocular trauma were significantly higher for males (2.10, 95% CI 1.40–3.15), and for labourers than for other occupations (2.50, 95% CI 1.62–3.86). Conclusions : Ocular trauma affects one in 25 people in this urban population in India, and one in 167 people in this population are estimated to be blind in at least one eye due to trauma. The majority of the trauma resulting in blindness occurs during childhood and young adulthood, and slightly more than half occurs while playing. Targeting mothers and children of lower socioeconomic strata in eye health awareness strategies to reduce blindness due to trauma needs to be considered in urban India. Key words : blindness, India, population‐based, trauma, urban.     

Trachoma and blindness in the Nile Delta: current patterns and projections for the future in the rural Egyptian population.

A population based survey of trachoma and blindness was conducted in a rural Nile Delta hamlet. Trachoma remains hyperendemic in this region. Active trachoma was common among preschool children; over half had moderate to severe disease. Of residents 25 years old 90% had substantial conjunctival scarring. Severe conjunctival scarring was commoner among women (84%) than men (58%), and three-quarters of older women had trichiasis/entropion compared with 57% of older men. Males and females had equivalent age specific rates of inflammatory disease. Blindness was associated with old age; 17% of residents aged 50 and over were blind. Estimates of blindness based on this survey and other surveys in Egypt indicate that blindness is still a serious public health problem in rural Egypt. The number of blind persons in Egypt will increase from an estimated 420,000 in 1980 to 868,000 by the year 2020. The current crude blindness rate of 1.8% is expected to increase to 2.3% in the year 2000 and to 3.2% in 2020.     

A survey of severe visual impairment in children attending schools for the blind in a coastal district of Andhra Pradesh in South India

Purpose

To identify the major causes of severe childhood visual impairment and blindness among students attending schools for the blind in a coastal district of Andhra Pradesh (AP) in South India.

Methods

Children ≤16 years of age attending six schools for the blind in the study area were interviewed and examined in the year 2009, and causes were classified according to the World Health Organization Program for Prevention of Blindness (WHO/PBL) childhood blindness proforma. A total of 113 children underwent a detailed eye examination by an experienced ophthalmologist.

Results

The major causes of blindness were congenital eye anomalies in 46 children (41.4; 95% confidence interval (CI): 32.3–50.6), followed by retinal disorders in 21 children (18.9% 95% CI: 11.6–26.2), cataract in 9 children (9.7% 95% CI: 2.9–12.9), and corneal conditions (scar and Staphyloma) in 8 children (7.1% 95% CI: 2.4–11.8). More than half the children (56.6%) were blind due to conditions that could have been treated or prevented.

Discussion

Congenital anomalies were found to be the most common cause of blindness. The majority of the cases were due to avoidable causes of blindness. Therefore, robust screening measures may help reduce the burden of visual impairment in children.     

Blindness incidence in Germany. A population-based study from Württemberg-Hohenzollern

Few data on the incidence of blindness in Germany are available. We analysed causes of legal blindness for the region Württemberg-Hohenzollern (population 5.5 million) in order to help fill in this gap. Material and Methods: Population-based investigation on the incidence of legal blindness (visual acuity <1/50) based on materials from the social services. Age-dependent blindness incidences were modelled via logistic regression models. Results: 647 blind persons were newly registered in 1994 (blindness incidence 11.6/100,000). The blindness incidence is moderate in infants (4.5/100,000) and decreases further during childhood. At the age of 20 years, the incidence again rises to the former level and remains relatively constant. After the age of 60 years, the incidence increases sharply: 5-year odds ratios are 1.76 (CI: 1.68-1. 85) in women and 1.72 (CI: 1.60-1.84) in men. The blindness incidence is higher in women, 15.6/100,000, compared to 12.2/100,000 in men. The major causes of blindness are: macular degeneration, 3. 92/100,000; diabetic retinopathy, 2.01/100,000; glaucoma, 1.6/100, 000; high myopia, 0.77/100,000; optic atrophy, 0.68/100,000; central nervous system-triggered blindness; 0.56/100,000, and tapetoretinal degenerations, 0.52/100,000. Discussion: Due to monetary incentives for the blind persons, social service files offer accurate and complete data. Besides macular degeneration, glaucoma and diabetic retinopathy are major causes of blindness. Thus, this study suggests further blindness prevention activities for diabetic retinopathy and glaucoma.     

Prevalence and causes of blindness in the northern Transvaal.

During November 1985 a survey was carried out to determine the prevalence and causes of blindness in the Elim Hospital district of Gazankulu in the Northern Transvaal, South Africa, and to assess the Eye Department's effectiveness in preventing blindness. Using a random cluster sample technique, we screened 18,962 of the estimated 71,200 inhabitants of the district (26.6%). We found 109 blind people. The prevalence of blindness was 0.57% (95% confidence interval 0.46%-0.68%). The main causes of blindness were senile cataract (55%), corneal scarring due to trachoma (10%), uncorrected aphakia (9%), and open-angle glaucoma (6%). There were 14 aphakic blind persons who did not have aphakia glasses (43% of all persons operated on for cataract). Women had a significantly higher prevalence of blindness than men. After the age of 60 years the prevalence of blindness increased sharply. Women were 1.6 times less likely to have undergone cataract surgery than men. The two most effective steps to reduce the prevalence of blindness in the Elim district further are to provide aphakia glasses to all aphakic patients and to improve the accessibility of the Eye Department's surgical services.     

Primary open-angle glaucoma presentation at a tertiary unit in Africa: intraocular pressure levels and visual status

AIM: To investigate the presentation of POAG at a tertiary referral hospital in East Africa, including intraocular pressures, visual status and management decisions. METHODS: Retrospective review of first-time presenters with POAG over a 6-month period. RESULTS: Of the 298 patients identified, mean age 57 years (n = 296, range = 14-88, SD = 14), 213 (72%) male, 122 (41%) had normal vision (using WHO better eye acuity criteria: visual impairment < 6/18, blind < 3/60) at presentation, 87 (30%) had visual impairment and 86 (29%) were blind. The mean presenting IOP was 32 mmHg (SD = 11) and 70% of the patients had a cup:disc ratio of 0.8 or worse in the better eye. Longer disease duration (OR = 1.20, 95% CI 1.04-1.39) and higher mean IOP (OR = 1.06, 95% CI 1.02-1.10) were associated with visual impairment or blindness. Intraocular pressure showed a negative linear correlation with presenting logMAR acuity (R(2) = 0.115, SE = 1.30, p < 0.0005). The mean IOP in eyes that had undergone trabeculectomy (19 mmHg, SD = 8, n = 17) was significantly (p < 0.0005) lower than that in eyes that had not (34 mmHg, SD = 12, n = 274). The referral rate for trabeculectomy was 158/275 (57%). Male sex (OR = 2.17, 95% CI 1.0-4.72), higher mean IOP (OR = 1.09, 95% CI 1.05-1.14) and not being blind (OR = 26.47, 95% CI 9.90-70.78) were associated with surgical referral. Of the 158 patients, 76 (48%) accepted surgery. CONCLUSIONS: A high proportion of patients presenting to our unit with POAG are visually impaired or blind and the higher their presenting IOP the poorer their visual acuity. Previous trabeculectomy was associated with lower IOPs and protection from visual impairment and blindness. Further training of clinic staff towards early surgical referral and investigation of gender barriers is required.     

Visual acuity in an Australian Aboriginal population

Background: Australia is a developed country, However; Aboriginal Australians have rates of blindness comparable to Third World countries. There have been well-funded eye health programs for 15 years in Central Australia. This paper examines if there has been an improvement in visual disability of one traditional group of Aboriginal Australians. Methods: Results from an eye health survey of the Anangu Pitjantjatjara of South Australia in 1990 are presented. These data are compared with results for ‘blindness’ and ‘poor vision’ from a national survey undertaken in 1976. The two surveys were comparable in design, both were cross-sectional population-based prevalence surveys. Prevalence rates were adjusted for the size of the source population. Results: Young rural Aboriginal Australians have good visual acuity. Low vision and blindness (WHO definitions) occur in 19.6% and 10.4% of 60+ year olds, respectively. Women were more likely than men to be blind or have low vision (OR= 1.93; 1.06-3.58). There was a decline in ‘poor vision’ between surveys (OR=2.86; 1.86-4.75) but not in ‘blindness’. Conclusion: Although there has been a reduction in the prevalence of visual disability in rural Aboriginal Australians, improvements in the provision of eye care for the elderly need to occur.     

Visual impairment and blindness in rural central India: the Central India Eye and Medical Study

Purpose: The aim of the study was to investigate prevalence of visual impairment in rural central India. Methods: The population‐based Central India Eye and Medical Study included 4711 subjects with an age of 30+ years. Presenting visual acuity (PRVA) and best‐corrected visual acuity (BCVA) were recorded. Visual impairment and blindness were defined using the World Health Organization (WHO) standard and United States (US) standard. Results: On the basis of PRVA and using WHO and US standards, 1049 [22%; 95% confidence interval (CI): 21.1, 23.5] subjects and 1290 (27%; 95% CI: 26.1, 28.7) subjects, respectively, were visually impaired, and 35 (0.7%; 95% CI: 0.5, 1.0) subjects and 116 (2.5%; 95% CI: 2.0, 2.9) subjects, respectively, were blind. The corresponding age‐standardized prevalence figures were 17%, 21%, 0.5% and 2%, respectively. Using best‐correcting glasses could eliminate PRVA‐visual impairment/blindness in 729 subjects (67% of all subjects with visual impairment/blindness). On the basis of BCVA and using WHO and US standards, 333 (7%; 95% CI: 6.3, 7.8) subjects and 473 (10%; 95% CI: 9.2, 10.9) subjects, respectively, had visual impairment, and 22 (0.5%; 95% CI: 0.3, 0.7) and 31 (0.7%; 95% CI: 0.4, 0.9) subjects, respectively, were blind. Corresponding age‐standardized prevalence figures were 5%, 8%, 0.4% and 0.5%, respectively. Causes for BCVA‐visual impairment/blindness were cataract (75%), postoperative posterior capsular opacification (4%), surgical complications (2%), corneal opacifications (2%), age‐related macular degeneration (2%), other macular diseases (1%), and glaucoma (1%). Conclusions: Age‐standardized prevalence of PRVA‐visual impairment/blindness (WHO definition) in the adult population of rural central India was 17%. Most frequent cause was undercorrected refractive error. Supply of correct glasses is the most efficient way to improve vision in the rural central India.