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Br J Ophthalmol 2004;88:486-490. doi: 10.1136/bjo.2003.020016 Background/aim: A current consensus in epidemiological studies of primary angle closure (PAC) is to diagnose the condition only if the posterior (usually pigmented) trabecular [...]

Aim: To determine the age, sex, and cause specific prevalences of blindness and visual impairment in adults 30 years of age and older in Bangladesh. Methods: A nationally representative sample [...]

Aim: To evaluate the outcome of cataract surgery in the population of Bangladesh. Methods: Data were collected by the National Blindness and Low Vision Prevalence Survey of Bangladesh, a cross [...]

Aim: To describe the methods used and initial results of a prospective study designed to determine whether screening and prophylactic treatment will reduce the incidence of primary angle closure glaucoma [...]

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 [...]

Aim: To relate indices of education, occupation, and socioeconomic status to acular dimensions and refraction in an adult populatian. Methods: A population based, crass sectional survey of adult Chinese aged [...]

Aim: Investigation of the natural history of trachomatous trichiasis in the Gambia and of the outcome of self epilation and surgery for the condition. Methods: A 1 year longitudinal study [...]

Aim: To utilise a novel method for making measurements in the anterior chamber in order to compare the anterior chamber angles of people of European, African, and east Asian descent [...]

Introduction The prevalence of severe blindness (defined as no light perception, or inability to see hand movements or count fingers at less than 25 cm) in various regions of Mongolia [...], The survey was conducted in 3 out of the 18 administrative regions (aimaks); 4345 people aged ≥ 40 years were examined, which represented 95.7% of the proposed sample. The prevalences of blindness and low vision in the sample were 1.5% (95% CI, 0.8-2.3%) and 8.1% (95% CI, 5.5-10.7%), respectively, from which the prevalences of blindness and low vision in the Mongolian population aged 40 years and older were estimated to be 1.4% and 7.7%, respectively. The prevalence of climatic droplet keratopathy was high (ranging from 15% to 50%) in this population, which included a large number of semi-nomadic cattle breeders, and was responsible for 7.2% of the blindness and 19.3% of the low vision. Cataract and glaucoma were the commonest blinding disorders, each accounting for around 35% of the blindness. Trauma accounts for a high proportion of those monocularly blind. Trachoma and xerophthalmia were not found.

No association between mortality and presence of lens changes was found among the non-diabetic population of Framingham, USA in the only published population-based study of survival in persons with and [...], The study was carried out in a rural population in central India. A random sample of 11 village communities provided 1020 persons aged 40-64 years, who were examined in 1982 and again reassessed in 1986. Statistical analysis, based on the Mantel-Haenszel method for stratified data, showed increased mortality in persons who had central lens opacities, compared with those who had trivial or no central lens opacities. The significant age-adjusted death ratio was just over 2 (2.2), as were the age/sex-adjusted and age/vision-adjusted estimates, which indicate doubling of mortality in the cataract cohort. Multiple regression analysis using the Cox proportional-hazards model gave very similar results. Statistical tests for homogeneity of death ratios across the various age/sex/vision strata were carried out, and the observed association between cataract and mortality was found to be consistent, both in males and in females, in the youngest and oldest age groups, and among those with adequate vision of 6/18 or better as well as among persons with serious visual impairment. There were no known diabetics in the study sample, which came from what could reasonably be regarded as a non-diabetic population.

An associative model of serial learning is described. The model is based on the assumption that the effective stimulus for a serial-list item is generated by adaptation-level coding of the item's ordinal position. The psychophysical concept of distinctiveness is used to quantify the strength of intralist competing associations. Illustrations are given on how the model may be used to generate predictions concerning the fundamental aspects of serial learning data: difficulty as a function of list length, performance as a function of amount of training, serial-position effects at various stages of learning, and the shape of the gradient of remote intrusions as a function of acquisition level.

Introduction Globally, cataract is the most frequent cause of blindness, affecting more than 20 million people (1). Most of these people live in rural areas of developing countries, where there [...], Most of the estimated 20 million people who are blind with cataracts live in rural areas of developing countries, where expert surgical resources are scarce. We have studied the use of multiflex open-loop anterior-chamber intraocular lenses (ACIOL)in high-volume low-cost surgery. Between 1992 and 1995, a total of 2000 people attending Lahan Eye Hospital, Nepal, with bilateral cataracts reducing vision to [is less than or equal to] 6/36 were randomly allocated to receive intracapsular extraction (ICCE) with aphakic spectacles, or ICCE with an ACIOL. We re-examined the cohort (1305/2000, 65%) between November 1996 and April 1997 and report the findings in this article. There were 13 new cases of poor visual outcome (best corrected vision [is less than] 6/60) arising after one year: 9 in the ACIOL group and 4 in the control group; odds ratio 2.1 (95% confidence interval, 0.59-9.55). The causes of poor outcome were as follows: ACIOL group -- retinal detachment (4 cases), cystoid macular oedema (2), epiretinal membrane (1), age-related macular degeneration (1), and late endophthalmitis (1); control group -- retinal detachment (2 cases), late endophthalmitis (1), and primary open-angle glaucoma with age-related macular degeneration (1). In rural areas of developing countries, well--manufactured multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction. Keywords: lenses, intraocular; cataract extraction; treatment outcome; vision, low; randomized controlled trials; Nepal. Voir page 376 le resume en francais. En la pagina 377 figura un resumen en espanol.

Aims This study aimed to evaluate a new chart designed to improve the collection of visual acuity data in population-based surveys. The Reduced logMAR E chart (RLME) employs three letters per line, ‘tumbling E’ optotypes, and conforms to accepted contemporary design principles.Methods The performance of the chart was assessed within a population-based glaucoma survey in Thailand. Performance indices were test-retest variability (TRV) and agreement with acuity data measured using the ETDRS logMAR chart which acted as the ‘gold standard’.Results The 95% confidence limits for TRV of RLME acuity data were ±0.15 logMAR. This figure is consistent with published data on the TRV of acuities measured using five-letter-per-line logMAR charts. The mean difference between RLME and ETDRS acuity data was 0.00 logMAR (95% confidence intervals of ±0.05 logMAR) indicating that RLME acuities agreed well with those of the ETDRS chart. The chart and its method of use was readily accepted by the local ancillary staff who required only minimal training before acuity measurement could be delegated to them.Conclusions The study demonstrated that the RLME chart is capable of accurate and repeatable acuity measurements. Certain aspects of the design of the RLME chart may be particularly pertinent to the measurement of vision in population-based surveys.Eye (2003) 17, 754-758. doi:10.1038/sj.eye.6700500 [ABSTRACT FROM AUTHOR]

BACKGROUND Few population-based eye surveys have been conducted in sub-Saharan Africa, limiting the quality of epidemiological information on visual loss from Africa. In the present paper, we describe the prevalence of visual loss in rural Uganda and the screening accuracy of E-optotypes when used by non-medical staff. METHODS Residents of 15 neighbouring villages were screened for visual loss (<6/18 in either eye) using Snellen's E-optotypes. Individuals who failed were initially referred to an ophthalmic clinical officer (OCO), who retested visual acuity and subsequently referred to an ophthalmologist to determine the cause of visual loss. Subjects from two villages (248 individuals) who passed visual acuity screening were re-examined by the OCO to estimate the accuracy of the screening procedure. RESULTS Of the 4076 adults (aged 13 years and over, 69.3% of the censused population) who participated, 191 (4.7%) failed the vision screening criteria and 648 (15.9%) had non-vision impairing conditions. The prevalence of visual loss was at least 3.9%: 0.4% had bilateral blindness, 1.6% had bilateral visual impairment, 0.7% had unilateral blindness and 1.2% unilateral visual impairment. Cataract was the leading cause for all categories of visual loss except bilateral blindness, for which suspected glaucoma was most frequent. Refractive errors were the second leading cause of bilateral and unilateral visual impairment. Based on one subject (0.4%) in the validation sample who was found to have low vision, we estimated the sensitivity and specificity of E-optotypes for detecting visual loss to be 93% and 99%, respectively. CONCLUSIONS Cataract and refractive errors were responsible for most of the visual loss in rural Uganda. Snellen's E-optotypes provide a suitable cost-saving tool for conducting population-based eye surveys in sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Aims National blindness surveys conducted in the Gambia in 1986 and 1996 showed an increase in blindness and visual impairment from non-trachomatous opacity. This study aimed to investigate the aetiology of these opacities and to assess the resulting visual burden. Methods A population-based, randomised blindness survey was conducted in the Gambia in 1996. Patients with visual impairment or blindness were examined by an ophthalmologist with a slit lamp. Causes of corneal opacity were determined as accurately as possible by clinical history and examination. Results A total of 154 patients with non trachomatous corneal opacity were examined of whom 39 had bilateral opacities and 115, unilateral. Causes included corneal infection, measles/vitamin A deficiency, harmful traditional practices and trauma (unilateral scarring). Overall, corneal pathology alone was responsible for bilateral visual impairment or blindness in 19 (12%) patients and unilateral visual impairment or blindness in 88 (57%) patients. Those patients with bilateral visual impairment or blindness (mean age 59, SD) were older (P = 0.003) than others (mean age 44, SD = 20). The use of harmful traditional eye practices was associated with bilateral corneal blindness or visual impairment (RR = 2.63, 95% CI 1.11-6.21, P = 0.04). Although none of the corneal scars reported here were attributed to trachoma, in patients over the age of 45, the prevalence of trachomatous conjunctival scarring in this group was 38.8% compared to 19.4% of the whole nationwide sample. Discussion Strategies for the prevention (including the quest for cheaper anti-microbial drugs and co-operation with traditional healers) and surgical treatment of these corneal opacities are discussed. [ABSTRACT FROM AUTHOR]