Prevalence Of Bilateral Blindness Research Articles

Prevalence and Causes of Blindness and Visual Impairment Among the Elderly in Rural Southern Harbin, China

Purpose: The purpose of this study was to estimate the prevalence and causes of visual impairment(VI) and blindness by a population-based survey in an elderly rural Chinese population. Methods: Cluster sampling was used to select samples. The protocol consisted of an interview, pilot study, visual acuity (VA) testing and a clinical examination. The definitions of blindness (VA < 20/400) and visual impairment (VA < 20/60 to ≥ 20/400) were based on the presenting VA in the better eye. The major causes of VI and blindness were identified. The associations of bilateral VI and blindness by age, gender and education were calculated through multiple logistic regression. Cataract surgical coverage (CSC) was also calculated. Results: Among the 5559 people entered in the project, 5057 were examined (91.0%), and of these 2383(47.1%) were men. The mean age was 60.5 (range, 50–96) years old. The prevalence of bilateral blindness and VI was 1.9% (95% confidence interval (CI): 1.6 % to 2.3%) and 8.3%(95% CI: 7.5 % to 9.1%), respectively. We found that age, female gender, and illiteracy were associated with bilateral blindness. The leading cause of bilateral blindness was cataract (70.4%), followed by corneal opacity (8.2%) and glaucoma (5.1%). The main causes for bilateral VI were refractive error (35.9%) and cataract (35.7%). The average CSC was 9.3% (95%CI: 6.7% to 11.7%). Conclusions: Cataract is the dominant cause of bilateral blindness and VI in people over 50 years old in rural southern Harbin. Specific prevention and VI rehabilitation programs should be developed for the elderly rural Chinese population.

A survey of blindness and low vision in Motuo county of Tibet

To investigate the status of blindness and low vision in Motuo county of Tibet. Random cluster sampling based on the village was adopted in this survey. Six villages were chosen as the survey venue. The sampling percentage was 2.05% in the whole population in the county. The criteria of blindness and low vision from World Health Organization were used in the survey. 821 individuals were registered. The rate of final participants was 89.52%. The prevalence of bilateral blindness and low vision was found to be 2.59% and 4.35% respectively. Subjects over 40 years old had a significantly higher prevalence of blindness and low vision. The causes leading to blindness and low vision were cataract (42.11%), corneal opacity (21.05%) and glaucoma (15.79%). The leading cause of blindness and low vision is cataract in Motuo county, therefore the surgical application in cases with cataract is the main measure in the treatment of blindness in the county.

Prevalence and causes of blindness and visual impairment in Limbe urban area, South West Province, Cameroon

Aim:To conduct a rapid assessment of cataract surgical services to estimate the prevalence and causes of blindness and visual impairment in members of the population aged ⩾40 years in the...

Blindness and Eye Disease in Cambodia

Purpose: To assess the prevalence and etiology of blindness and low vision and to assess the prevalence of common eye diseases in central Cambodia. Methods: In this cross-sectional, population-based study, 6,558 residents of Kandal Province, Cambodia were registered, and 5,803 (88.5%) were interviewed and examined. This house-to-house survey was conducted by a team consisting of a senior ophthalmologist, a Cambodian eye doctor, and eight Cambodian eyecare workers. Results: The prevalence of bilateral blindness (visual acuity <3/60) is 1.1% (95% confidence interval [CI], 0.9–1.4), and an additional 4.4% (95% CI, 3.9–5.0) have low vision (visual acuity < 6/18, ≥3/60 in the better eye). The major causes of bilateral blindness are cataract (67.4%), phthisis (6.1%), uncorrected refractive error (6.1%), corneal scar (5.3%), uncorrected aphakia (3.0%), trachoma corneal scar (3.0%), optic atrophy (3.0%), and others (6.1%). The major causes of low vision are uncorrected refractive error (49.8%) and cataract (42.7%). The prevalence of unilateral blindness is 1.2% (95% CI, 0.9–1.4), often caused by cataract, corneal scar, or phthisis. Trauma due to landmine explosions and war-related injuries was frequently the underlying etiology in subjects with phthisis, corneal scarring, or other pathology.Conclusions: The prevalence of blindness and low vision in Cambodia is relatively high compared to other developing countries. Most of the causes of blindness and low vision are treatable or preventable. Landmines and other war-related injuries are an important cause of ocular injury. These results will assist in developing a national plan for the prevention of blindness in Cambodia.

Rapid Assessment of Avoidable Blindness in Nakuru District, Kenya

To estimate the prevalence of avoidable blindness in > or =50-year-olds in Nakuru district, Kenya, and to evaluate the Rapid Assessment for Avoidable Blindness (RAAB), a new methodology to measure the magnitude and causes of blindness. Cross-sectional population-based survey. Seventy-six clusters of 50 people 50 years or older were selected by probability proportionate to size sampling of clusters. Households within clusters were selected through compact segment sampling. Three thousand seven hundred eighty-four eligible subjects were selected, of whom 3503 (92.6%) were examined. Participants underwent a comprehensive ophthalmic examination in their homes by an ophthalmologist, including measurement of visual acuity (VA) with a tumbling-E chart and the diagnosis of the principal cause of visual impairment. Those who had undergone cataract surgery were questioned about the details of the operation and their satisfaction with surgery. Those who were visually impaired from cataract were asked why they had not gone for surgery. Visual acuity and principal cause of VA<6/18. The prevalence of bilateral blindness (presenting VA < 3/60) was 2.0% (95% confidence interval [CI], 1.5%-2.4%), and prevalence of bilateral visual impairment (VA of <6/18-> or =6/60) was 5.8% (95% CI, 4.8%-6.8%) in the sample. Definite avoidable causes of blindness (i.e., cataract, refractive error, trachoma, and corneal scarring) were responsible for 69.6% of bilateral blindness and 74.9% of bilateral visual impairment. Cataract was the major cause of blindness (42.0%) and visual impairment (36.0%). The cataract surgical coverage was high, with 78% of those with bilateral cataract who needed surgery having had surgery at VA<3/60. The quality of surgery was of concern because 22% of the 222 eyes that had undergone cataract surgery had VA<6/60 with best correction. The main barriers to surgery were lack of awareness and cost. The RAAB methodology was easy to use, and each team could visit one cluster per day. The prevalence of blindness in > or =50-year-olds in Nakuru district was low, in part due to the high cataract surgical coverage. The RAAB is easy to use and inexpensive and provides information about the magnitude and causes of avoidable blindness that can be used for planning and monitoring eye care services.

Prevalence of blindness and visual impairment in the region of Ségou, Mali. A baseline survey for a primary eye care programme.

A community-based cross-sectional study on the prevalence and causes of blindness and visual impairment was conducted between July and August 1990 in three rural districts in Ségou region, Mali. The study population consisted of 5871 villagers. In the study area, the overall prevalence of bilateral blindness was 1.7% (standardized rate for age 2.0% +/- 0.4%), of bilateral visual impairment 1.7% (2.1% +/- 0.4%), of unilateral blindness 1.7% (2.2% +/- 0.4%) and of unilateral visual impairment 1.0% (1.2 +/- 0.3%). No important differences were found between districts. Cataract was the most common cause of visual loss (54%) and was most prevalent among those over 50 years of age. In 43%, unilateral blindness was associated with trauma. Other major eye diseases accounting for high percentages of visual impairment were trachoma and glaucoma. Xerophthalmia appeared to be a major public health problem among children in the age group 0-5. It was concluded that blindness is a major public health problem in this region. Some recommendations are given for strengthening integrated primary eye care at the district level in Ségou region.

Retinopathy of prematurity in infants weighing 1000‐1499 g at birth

To review the incidence and severity of retinopathy of prematurity (ROP) in infants with birthweights 1000-1249 g and 1250-1499 g, to establish whether the upper weight limit for routine ophthalmological examination might safely be lowered. Prospective cohort study of infants born between 1 January 1977 and 31 December 1992 cared for in the neonatal nurseries at the Royal Women's Hospital, Melbourne. Data were retrieved on 1373 infants who survived their initial hospitalization. They comprised 657 with birthweights 1000-1249 g (group 1) and 716 with birthweights 1250-1499 g (group 2). There were 76 outborn infants in group 1 and 97 in group 2; the remaining infants were all born at the Royal Women's Hospital. Ocular examinations commenced at 2 weeks of age, when possible, and at 2-weekly intervals after that. In group 1, ROP was detected in 14.6% (96/657) and severe ROP (bilateral stage 3-5) in 5.0% (33/657). Five (0.8%) children required surgical intervention (reaching threshold disease); following surgery, one was legally blind, one had severely impaired vision, and the other three had near-normal vision. Another child was blind; he was born at 28 weeks gestational age with a birthweight of 1170 g, and was transferred to a Level II hospital at 9 weeks chronological age with no detectable retinopathy. He returned 1 year later totally blind with detached retinae (grade 5 ROP). The prevalence of bilateral blindness in this group was 0.3% (2/657). In group 2, ROP was detected in 6.4% (46/716) and severe ROP in 0.8% (6/716). No children required surgery; three were found to be myopic at follow-up but the corrected visual acuity was normal. No children in group 2 were blind. No significant difference was found between the rates of ROP in inborn and outborn infants. In neonatal units with similar rates of ROP and visual outcome, routine ophthalmological examination in the neonatal nursery of infants weighing more than 1249 g at birth is probably unnecessary.

Prevalence of blindness and low vision of people over 30 years in the Wenchi district, Ghana, in relation to eye care programmes.

A population based survey on the prevalence of major blinding disorders was conducted in the Wenchi district in central Ghana between March and May 1991. In 10 villages, 1425 people of 30 years and older were screened, using the WHO eye examination record. The prevalence of bilateral blindness above 30 years proved to be 1.7% (best acuity < 3/60): the prevalence of low vision above 30 years was 2.0% (best visual acuity 6/18 to 3/60). The causes of blindness were determined as cataract (62.5%), onchocerciasis (12.5%), corneal opacity (non-trachomatous) (8.2%), refraction anomalies (4.2%), phthisis bulbi (4.2%), optic atrophy (4.2%), and vascular retinopathy (4.2%). In the Wenchi district, 1.0% of the population over the age of 30 years was found to need a cataract extraction because of blindness of both eyes. Another potential 1.0% needs a cataract extraction because of low vision. A minor second study (n = 149) was undertaken in the same district, but in a village in an area near the Black Volta river in which onchocerciasis is endemic. The prevalence of blindness (8.1%) and low vision (3.4%) caused by onchocerciasis and cataract both proved to be higher. The survey provided the basis for a preventive and curative eye care programme.

Prevalence and causes of vision loss in central Tanzania

A population-based survey of the prevalence of major blinding disorders was conducted in three villages in central Tanzania. Overall, 1827 people over the age of seven years old were examined. In those age seven and older, the prevalence of bilateral blindness (visual acuity in the better eye of less than 3/60) was 1.26% and monocular blindness (visual acuity of less than 3/60 in one eye) was 4.32% and the prevalence of visual impairment (visual acuity less than 6/18 but greater than or equal to 3/60 in both eyes was 1.04% and in one eye was 1.75%. Corneal opacities were responsible for 44% of bilateral and 39% of monocular blindness and resulted from trachoma, measles often in association with Vitamin A deficiency, keratoconjunctivitis, and the use of traditional eye medicines. Cataracts accounted for 22% of bilateral and 6% of monocular blindness. Readily preventable or reversible causes of blindness were responsible for 65% of cases of bilateral and 46% of monocular blindness.

Prevalence and causes of blindness: Results from the rapid assessment of avoidable blindness survey in gezira state, sudan

Objectives: To estimate the prevalence of avoidable blindness in people aged 50 years and older in Gezira state, Sudan, using the Rapid Assessment for Avoidable Blindness methodology. Design: Cross-sectional, population-based survey. Participants: Forty-three clusters of 50 people aged 50 years or older were selected by probability proportionate to size sampling of clusters. Households within clusters were selected through compact segment sampling. A total of 2150 eligible persons were selected, of whom 2103 (97.8%) persons were examined. Materials and Methods: Participants underwent a comprehensive ophthalmic examination in their homes by specially trained ophthalmic teams, including measurement of visual acuity (VA) with a tumbling-E chart and the diagnosis of the principal cause of visual impairment. Results: The prevalence of bilateral blindness (presenting VA <3/60) was 9.37% (95% confidence interval [CI] ±1.95) and the prevalence of bilateral visual impairment (VA of <6/18-6/60) was 3.9% (95% CI ±1.10) in the sample. Definite avoidable causes of blindness (i.e., cataract, refractive error, trachoma and corneal scarring) were responsible for 74.6% of bilateral blindness. Cataract was the major cause of blindness (57.4%), followed by glaucoma (17.3%). Conclusions: The prevalence of blindness in people aged 50 years and older in Gezira state was slightly higher than that expected. Than main cause of blindness was cataract, followed by glaucoma. Three quarters of blindness was due to avoidable causes.