Five‐year incidence of visual impairment and blindness in older Icelanders: the Reykjavik Eye Study

Purpose: This study examined age, sex and cause‐specific 5‐year incidence of visual impairment and blindness in a middle‐aged and elderly Icelandic population. Methods: The study cohort consisted of a population‐based, random sample of citizens aged ≥ 50 years. Of 1379 eligible subjects, 1045 underwent a baseline examination in 1996; 846 of the 958 survivors (88.2%) underwent a 5‐year follow‐up examination in 2001. All participants underwent an extensive ophthalmological examination including best corrected visual acuity (BCVA) using a Snellen chart. We used World Health Organization (WHO) criteria, which define visual impairment as BCVA in the better eye of < 6/18 and ≥ 3/60 and blindness as BCVA in the better eye of < 3/60. We also used US criteria, which consider BCVA of < 6/12 and > 6/60 in the better eye to represent visual impairment and BCVA of ≤ 6/60 in the better eye to represent blindness. The causes of incident visual loss in either eye were determined. Deterioration or improvement in vision were defined as a loss or gain of ≥ 2 Snellen lines. Results: According to WHO criteria, 5‐year incidence of bilateral visual impairment and blindness were 1.07% (95% confidence interval [CI] 0.37–1.76) and 0.35% (95% CI 0.00–0.76), respectively. Using US criteria, equivalent incidence of bilateral visual impairment and blindness were 3.49% (95% CI 2.24–4.74) and 0.95% (95% CI 0.29–1.60), respectively. Age‐related macular degeneration and cataract were the major causes of incident visual impairment and blindness. Conclusions: Incidences of visual impairment and blindness increased significantly with age. Age‐related macular degeneration, present in 75% of affected persons, was the most common cause of 5‐year incident legal blindness in this middle‐aged and elderly Icelandic population.     

Prevalence and causes of visual impairment and blindness in Icelanders aged 50 years and older: the Reykjavik Eye Study

Purpose: This study aimed to study the prevalences and causes of visual impairment and blindness in an Icelandic adult population. Methods: The Reykjavik Eye Study includes a random sample of citizens of Reykjavik aged ≥ 50 years, with an equal proportion (6.4%) for each year of birth and each sex. A total of 1045 persons were examined, representing a response rate of 75.8%. All participants underwent an extensive ophthalmological examination using a standard protocol. We used World Health Organization (WHO) definitions for bilateral visual impairment (best corrected visual acuity [VA] < 6/18 or visual field of ≥ 5 ° and < 10 ° around the fixation point in the better eye) and blindness (VA < 3/60 or visual field < 5 ° in the better eye). We also used US criteria, which define bilateral visual impairment as present if VA is < 6/12 and blindness as present if VA is ≤ 6/60 (both in the better eye). The causes of visual loss were determined for all participants found to be visually impaired in one or both eyes. Results: The prevalences of bilateral visual impairment and blindness were 0.96% (95% confidence interval [CI] 0.37–1.55) and 0.57% (95% CI 0.12–1.03), respectively, using the WHO criteria, and 2.01% (95% CI 1.16–2.86) and 0.77% (95% CI 0.24–1.29), respectively, using the US criteria. The prevalence rates were 4.40% and 5.45% for unilateral visual impairment and 1.72% and 3.06% for unilateral blindness, using the WHO and US criteria, respectively. Age‐related macular degeneration (AMD) was the major cause of bilateral visual loss, whereas the most common causes of unilateral visual loss were, in this order, amblyopia, cataract and glaucoma. Conclusions: Prevalence of visual loss increases with age. The leading cause of bilateral visual impairment and blindness was AMD, accounting for more than half of all cases, and cases of geographic atrophy outnumbered those of exudative AMD by two to one.     

Prevalence and causes of visual impairment in a rural North‐east China adult population: a population‐based survey in Bin County,Harbin

Acta Ophthalmol. 2010: 88: 669–674

Abstract.

Purpose: To investigate the prevalence and causes of visual impairment in a rural population in north‐east China. Methods: A population‐based study was conducted within Bin County, Harbin of north‐east China. Low vision and blindness were defined using the World Health Organization categories of visual impairment. The prevalence of visual impairment was estimated, and causes were identified based on best‐corrected visual acuity (BCVA) as well as presenting visual acuity (VA). Results: Out of 5764 people, 4956 (86.01%) aged older than 40 participated in the study. The prevalence of visual impairment, low vision and blindness based on presenting VA was 9.6% (BCVA, 6.6%), 7.7% (BCVA, 4.9%) and 1.9% (BCVA, 1.7%), respectively. Taking the presenting VA, cataract (44%) was the most common cause for visual impairment followed by uncorrected refractive error (24%), treatable causes of visual impairment accounted for 68% of the total cases. Cataract (59%) and glaucoma (15%) were leading causes for blindness based on presenting VA. According to BCVA, cataract was the leading cause of visual impairment and blindness (58% and 60%, respectively), followed by glaucoma (17% and 15%, respectively). The prevalence of visual impairment was higher among women than men (p < 0.0001) and increasing with age (p < 0.0001) and decreasing with increasing education level (p = 0.0075). Conclusion: Visual impairment was a serious public health problem in this rural population, with most of it easily remedied. Results highlighted the need for visual impairment prevention programs to an increasing number of elderly people, with a special emphasis on female and those with little or no education.     

Burden of moderate visual impairment in an urban population in southern India

OBJECTIVE: To assess the prevalence and causes of moderate visual impairment in an urban population in southern India. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 2522 (85.4% of the eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city. TESTING: The eligible subjects underwent a detailed ocular evaluation, including logarithm of the minimum angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, cataract grading, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated by standardized criteria. MAIN OUTCOME MEASURE: Moderate visual impairment was defined as presenting distance visual acuity less than 20/40 to 20/200 or visual field loss by predefined standardized conservative criteria in the better eye. RESULTS: In addition to the 1% prevalence of blindness in this sample reported earlier, moderate visual impairment was present in 303 subjects, an age-gender-adjusted prevalence of 7.2% (95% confidence interval [CI], 4.5%-9.9%; design effect, 2.7). The major cause of moderate visual impairment was refractive error (59.4%, 95% CI, 52.3%-66.5%) followed by cataract (25.3%, 95% CI, 19%-31.6%). Multivariate analysis showed that the prevalence of moderate visual impairment was significantly higher in those 40 years of age or older (odds ratio, 10.9; 95% CI, 8-15) and females (odds ratio, 1.89; 95% CI, 1.41-2.53) and lower in those belonging to the highest socioeconomic status (odds ratio, 0.27; 95% CI, 0.14-0.51). However, because of the pyramidal age distribution of the population, 38.1% of the total moderate visual impairment was present in those younger than 40 years of age. The proportion of moderate visual impairment caused by refractive error was higher in the younger than in the older age groups (P < 0.0001). CONCLUSIONS: Projecting the results to the 26.5% urban population of India, there would be 18.4 million (95% CI, 11.5-25.2 million) persons with moderate visual impairment in urban India alone. Refractive error was the major cause of moderate visual impairment in the population studied. The absolute proportion of moderate visual impairment in those younger than 40 years of age was considerable. The eyecare policy of India, apart from dealing with blindness, should address the issue of the relatively easily treatable uncorrected refractive error as the cause of moderate visual impairment in an estimated 10.9 million persons in urban India.     

Visual impairment in the 40- to 64-year-old population of Shahroud, Iran

Purpose

To determine the prevalence of visual impairment by age and gender in Shahroud.

Methods

Using random cluster sampling, 6311 Shahroud inhabitants who were between 40 and 64 years old were invited for ophthalmological examinations. Visual acuity worse than 0.5 LogMAR (20/60) and 1.3 LogMAR (20/400) in the better eye was regarded as low vision and blindness, respectively. The cause of blindness was determined by an ophthalmologist and in a person with more than one cause, the most correctable cause was regarded as the main cause.

Results

This study was conducted on 5190 participants (response rate: 82.2%). On the basis of presenting visual acuity, the prevalence of low vision and blindness was found to be 1.8% (95% confidence interval (CI): 1.4–2.10) and 0.5% (95% CI: 0.3–0.7), respectively. Based on corrected vision, these values were 0.5% (95% CI: 0.3–0.7) and 0.3% (95% CI: 0.1–0.4), respectively. Visual impairment increased with age in women (P<0.001). Uncorrected refractive errors (63.9%), cataract (20.2%), and amblyopia (5.9%) were the most common causes of visual impairment based on presenting vision. Based on corrected vision, however, cataract (42.5%), amblyopia (12.5%), and retinitis pigmentosa (7.5%) were the most common causes of visual impairment.

Conclusion

Although the prevalence of visual impairment in the city of Shahroud was determined to be lower than two previous studies in the country, correction of refractive errors and cataract could minimize the rate of visual impairment in this population as they were shown to comprise 85% of the causes of visual impairment. The elderly women need to receive more attention.     

Changing trends in the prevalence of blindness and visual impairment in a rural district of India: Systematic observations over a decade

Context : Globally, limited data are available on changing trends of blindness from a single region. Aims : To report the changing trends in the prevalence of blindness, visual impairment (VI), and visual outcomes of cataract surgery in a rural district of Andhra Pradesh, India, over period of one decade. Settings and Design : Rural setting; cross-sectional study. Materials and Methods : Using a validated Rapid Assessment of Cataract Surgical Services (RACSS) method, population-based, cross-sectional survey was done in a rural district in the state of Andhra Pradesh, India. Two-stage sampling procedure was used to select participants ≥50 years of age. Further, a comparative analysis was done with participants ≥50 years from the previously concluded Andhra Pradesh Eye Disease Study (APEDS) study, who belonged to the same district. Statistical Analysis : Done using 11 th version of Stata. Results : Using RACSS, 2160/2300 (93.9%) participants were examined as compared with the APEDS dataset (n=521). Age and sex adjusted prevalence of blindness in RACSS and APEDS was 8% (95% CI, 6.9-9.1%) and 11% (95% CI, 8.3-13.7%), while that of VI was 13.6% (95% CI, 12.2-15.1%) and 40.3% (95% CI, 36.1-44.5%), respectively. Cataract was the major cause of blindness in both the studies. There was a significant reduction in blindness following cataract surgery as observed through RACSS (17.3%; 95% CI, 13.5-21.8%) compared with APEDS (34%; 95% CI, 20.9-49.3%). Conclusion : There was a significant reduction in prevalence of blindness and VI in this rural district of India over a decade.     

Prevalence of visual impairment in adults with intellectual disabilities in the Netherlands: cross-sectional study

PURPOSE: To obtain the first representative and valid population-based prevalence figures on visual impairment and blindness in adults with intellectual disabilities (ID) and to identify risk groups. METHODS: STUDY DESIGN: Cross-sectional survey. An age-Down's syndrome-stratified random sample of 1,598 persons from a base population of 9,012 adult users of ID services with mild to profound intellectual disabilities was screened. Participants underwent protocollised on-site screening of visual functions. Results were related to degree of ID, occurrence of Down's syndrome (DS) and age. MAIN OUTCOME MEASURE: Prevalences of visual impairment and blindness in the study population and in subgroups and weighted prevalences in the total Dutch population using ID services. RESULTS: Prevalences of visual impairment ranged from 2.2% (95% confidence interval (CI), 0.5-6.4) in young adults with mild ID and no Down's syndrome to 66.7% (95% CI, 41.0-86.7) in older adults with profound ID and Down's syndrome; prevalences of blindness ranged from 0.7% (95% CI, 0.1-4.1) to 38.9% (95% CI, 28.1-50.3). Weighted prevalences of visual impairment and blindness in the total Dutch population of adult users of intellectual disability services are 13.8% (95% CI, 9.3-18.4) and 5.0% (95% CI, 3.8-6.2), respectively. Prior to this study, visual impairment or blindness had remained undiagnosed in 106/261 (40.6%) persons. CONCLUSIONS: As compared to published figures for the general Dutch population aged 55 years and over (visual impairment 1.4%, blindness 0.5%), prevalences of visual impairment and blindness are higher in all subgroups with intellectual disabilities, including the young and mildly handicapped group. The diagnosis is too often missed. All persons with severe or profound intellectual disabilities, and all older adults with Down's syndrome, should be considered visually impaired until proved otherwise.     

Prevalence and Causes of Visual Impairment and Blindness in Adults Aged 45 Years and Older from Parintins: The Brazilian Amazon Region Eye Survey

Purpose: To determine the prevalence and causes of visual impairment and blindness in adults aged 45 years and older from Parintins, Brazilian Amazon Region.

Methods: A random cluster sampling method was used to identify subjects 45 years of age and older from urban and rural census sectors of Parintins city, Amazonas State, from March 2014 to May 2015. Participants underwent a detailed ocular examination, including presenting (PVA) and best corrected visual acuity (BCVA). The main cause of PVA<20/32 per eye was determined.

Results: A total of 2384 subjects were enumerated and 2041 (85.6%) examined. The prevalence of presenting mild visual impairment – MiVI (<20/32 – ≥20/63) in the better-seeing eye was 17.0% [95% CI: 15.3–18.7%], and 8.5% [95% CI: 7.3–9.7%] with best correction. The prevalence of presenting moderate visual impairment – MVI (<20/63 – ≥20/200) was 18.4% [95% CI: 16.2–20.6%], and 6.9% [95% CI: 5.8–8.0%] with best correction. The prevalence of presenting bilateral VA <20/200 was 4.3% [95% CI: 3.6–5.0%], and 3.3% [95% CI: 2.5–4.0%] with best correction and increased with older age. Cataract (47.8%) and glaucoma (7.5%) were its main causes. In less severely affected eyes, uncorrected refractive errors (MVI: 42.6%; MiVI: 79.0%), cataract (MVI: 40.6%; MiVI: 13.7%) and pterygium (MVI: 7.6%; MiVI: 2.7%) were the main causes.

Conclusions: Most cases of visual impairment in Parintins are either preventable or treatable, and public health initiatives should target cataract surgical services and refraction with spectacle provision.     

The Current Status of Visual Disability in the Elderly Population of Taiwan

Purpose This study was conducted to explore the prevalence and the associated factors of visual impairment and blindness among the elderly Taiwanese population.Methods A nationwide population-based visual health care screening program of elderly people aged 65 years or older was conducted between 1 July 2002 and 31 December 2002 in Taiwan. Based on the same standardized protocol used by the Bureau of Health Promotion, Department of Health, and a stratified random sampling design, 3160 out of 5000 elderly subjects were selected by a two-stage visual care screening method. The overall response rate was 63.2%.Results The mean age of the elderly participants was 72.4 ± 5.1 years. The overall prevalence of glaucoma, corneal diseases, trauma, cataracts, myopic or diabetic retinopathy, and age-related macular degeneration among the elderly population was 2.1%, 6.3%, 0.9%, 60.2%, 7.5%, and 2.9%, respectively. The overall prevalence of visual disability (visual acuity of the better eye <0.5) was 17.7%, including 17.1% with visual impairment and 0.6% with blindness. Based on logistic regression, the significant independent factors of visual disability (visual impairment plus blindness) were sex (male vs. female, odds ratio (OR) = 0.62, 95% confidence interval (CI), 0.51–0.76), age (70–74 years vs. 65–69 years, OR = 1.60, 95% CI, 1.24–2.06; 75–79 years vs. 65–69 years, OR = 2.52, 95% CI, 1.92–3.32, 80yrs vs. 65–69yrs, OR = 4.86, 95% CI, 3.52–6.70), corneal diseases (OR = 2.26, 95% CI, 1.61–3.16), myopic or diabetic retinopathy (OR = 1.69, 95% CI, 1.20–2.39), age-related macular degeneration (OR = 4.96, 95% CI, 3.16–7.78), and cataract (OR = 3.40, 95% CI, 2.67–4.33).Conclusions The geographic difference in the prevalence of vision-related eye disease, visual impairment, and blindness point to the importance of taking actions that suit local circumstances. Our results also revealed that visual impairment and blindness are important visual health problems in the elderly Taiwanese population. Age-related macular degeneration, cataracts, corneal diseases, myopic or diabetic retinopathy, female sex, and aging were the leading causes of visual disability. Further organized preventive strategies for eye care are recommended in this population. Jpn J Ophthalmol 2005;49: 166–172 © Japanese Ophthalmological Society 2005     

Prevalence and causes of low vision and blindness in an urban population: The Chennai Glaucoma Study

Aim:

To evaluate the prevalence and causes of low vision and blindness in an urban south Indian population.

Settings and Design:

Population-based cross-sectional study. Exactly 3850 subjects aged 40 years and above from Chennai city were examined at a dedicated facility in the base hospital.

Materials and Methods:

All subjects had a complete ophthalmic examination that included best-corrected visual acuity. Low vision and blindness were defined using World Health Organization (WHO) criteria. The influence of age, gender, literacy, and occupation was assessed using multiple logistic regression.

Statistical Analysis:

Chi-square test, t-test, and multivariate analysis were used.

Results:

Of the 4800 enumerated subjects, 3850 subjects (1710 males, 2140 females) were examined (response rate, 80.2%). The prevalence of blindness was 0.85% (95% CI 0.6–1.1%) and was positively associated with age and illiteracy. Cataract was the leading cause (57.6%) and glaucoma was the second cause (16.7%) for blindness. The prevalence of low vision was 2.9% (95% CI 2.4–3.4%) and visual impairment (blindness + low vision) was 3.8% (95% CI 3.2–4.4%). The primary causes for low vision were refractive errors (68%) and cataract (22%).

Conclusions:

In this urban population based study, cataract was the leading cause for blindness and refractive error was the main reason for low vision.     

Awareness of eye donation in an urban population in India.

PURPOSE: Awareness of eye donation and willingness to pledge eyes for donation was assessed in the urban population of Hyderabad, India, where corneal blindness is a significant problem. METHODS: A total of 2522 subjects of all ages, representative of the Hyderabad population, participated in the Andhra Pradesh Eye Disease Study. Subjects >15 years old were interviewed regarding awareness of eye donation and willingness to pledge eyes for donation. RESULTS: Age-gender-adjusted prevalence of awareness of eye donation was 73.8% (95% CI: 66.5-81.0%) but only 1.9% (95% CI: 0.16-3.66%) had pledged eyes. With multivariate analysis, significantly less awareness of eye donation was found in illiterate subjects (OR 0.1; 95% CI: 0.1-0.14), subjects > or =70 years old (OR 0.3; 95% CI: 0.2-0.6), subjects of lower socio-economic status (OR 0.4; 95% CI: 0.3-0.6), females (OR 0.6; 95% CI: 0.5-0.8) and Muslims (OR 0.7; 95% CI: 0.6-0.9). Media was the major source of information about eye donation. Of those aware of eye donation, 44.9% were willing to pledge eyes. Willingness to pledge eyes for donation was significantly lower in Muslims (OR 0.18; 95% CI: 0.13-0.24) than in Hindus and in subjects > or =60years old (OR 0.3; 95% CI: 0.2-0.5). CONCLUSIONS: These data show that although only a few had pledged eyes there is enough potential in this population for obtaining many more corneas for transplantation. The information about distribution and demographic associations of awareness and willingness for eye donation could help in developing strategies to increase procurement of corneas for dealing with corneal blindness.     

A population-based survey of visual impairment and its correlates in Mahabubnagar district,Telangana State,India

Purpose: To estimate the prevalence and correlates of visual impairment in Mahabubnagar district, Telangana, India.

Methods: Fifty-one clusters of 80 people (all ages) were sampled with probability proportionate to size. Households within clusters were selected through the compact segment sampling. Visual acuity (VA) was measured with a tumbling “E” chart. An Ophthalmic Assistant or Vision Technician examined people with VA<6/12 in either eye. Other impairments (hearing, physical) were clinically assessed and self-reported functional difficulties measured using the Washington Group Extended Set. People with visual impairment and age-sex matched controls with normal vision were interviewed about poverty, employment and education.

Results: 4,125 people were enumerated and 3,574 screened (86.6%). The prevalence of visual impairment (VA<6/12) was 8.0% (95% CI = 6.9–9.4%) and blindness was 0.4% (0.2–0.9%), and both increased rapidly with age. Uncorrected refractive error was the leading cause of visual impairment, and cataract the leading cause of blindness. Cataract surgical coverage (proportion of all cataracts that had received surgery) was relatively low (41% of people at VA<6/60), while the post-surgery outcomes were good (81% of operated eyes had presenting VA≥6/18). Among the 287 people with visual impairment, 15% had a moderate/severe physical impairment or epilepsy and 25% had a moderate/severe hearing impairment. Self-reported difficulties in vision were relatively closely related to visual acuity. People with visual impairment were more likely to be in the poorest quartile (OR = 1.9, 95% CI = 1.0–3.4) or unemployed (5.0, 2.2–10.0), compared to controls.

Conclusions: Visual impairment was common in Mahabubnagar district, was mostly avoidable, and was correlated with poverty markers.     

Four-year incidence of visual impairment: Barbados Incidence Study of Eye Diseases

OBJECTIVE: To describe the 4-year incidence of visual impairment and causes of blindness among black participants of the Barbados Eye Studies. DESIGN: Population-based incidence study. SETTING AND PARTICIPANTS: The Barbados Incidence Study of Eye Diseases (BISED) followed the cohort of the Barbados Eye Study (BES), a prevalence study based on a simple random sample of Barbadians 40 to 84 years of age. BISED included 3193 black participants from the original cohort (85% of those eligible). MAIN OUTCOME MEASURES: Best-corrected visual acuity (Ferris-Bailey chart) at baseline and follow-up was measured according to a modified Early Treatment of Diabetic Retinopathy Study protocol. By use of World Health Organization (WHO) criteria, low vision and blindness for an individual were defined as visual acuity (VA) <6/18 to 6/120 and <6/120, respectively, in the better eye. By commonly used US criteria, low vision and blindness were defined as VA < or = 20/40 and < or = 20/200, respectively. Vision loss was defined as a doubling of the visual angle (i.e., decrease of 15 letters or more read correctly between baseline and follow-up examinations). Progression was defined as vision loss among those with low vision at baseline. RESULTS: On the basis of WHO criteria, the overall 4-year incidence was 3.6% (95% confidence interval [CI], 3.0%-4.4%) for low vision and 0.6% (95% CI, 0.4%-1.0%) for blindness. Incidence rates were higher using US criteria: 5.3% (95 % CI, 4.5%-6.2%) and 1.5% (95% CI, 1.1%-2.0%), respectively, reaching 21.5% and 7.3% for persons aged 70 years or older at baseline. One tenth of the cohort had vision loss, and 28.6% of those with low vision progressed. About one half of incident blindness was due to age-related cataract. Nearly one fifth was caused by open-angle glaucoma (OAG) alone or combined with cataract, and approximately 10% was caused by diabetic retinopathy (DR). CONCLUSIONS: The incidence of visual impairment was high in this Afro-Caribbean population, particularly in older age groups, indicating the public health significance of visual loss for this and similar black populations. Cataract, OAG, and DR were among the leading causes of incident blindness, paralleling their high prevalence in this population.     

Causes of blindness, low vision, and questionnaire-assessed poor visual function in Singaporean Chinese adults: The Tanjong Pagar Survey

OBJECTIVE: To determine the prevalence rates and causes of low vision, blindness, and patient-assessed deficient visual function among Singaporean Chinese adults. DESIGN: Population-based cross-sectional survey. PARTICIPANTS: Singaporean Chinese adults 40 to 79 years old (n = 1152). METHODS: From an initial sampling frame of 40- to 79-year-old Chinese in the Tanjong Pagar district in Singapore, 2000 subjects were selected using a disproportionate, stratified, clustered, random-sampling method. Of 1717 eligible subjects, 1232 were examined (participation rate = 71.8%), and 80 adults who did not have visual acuity (VA) data were excluded from the analysis. MAIN OUTCOME MEASURES: Bilateral low vision was defined as best-corrected VA (BCVA) worse than 6/18 and 3/60 or better, and bilateral blindness as BCVA worse than 3/60 in the better eye or constriction of the visual field to within 10 degrees of fixation, in accordance with the World Health Organization criteria. Patient-assessed visual function was measured using a modified VF-14 questionnaire. RESULTS: The age- and gender-adjusted prevalence rates were 1.1% (95% confidence interval [CI], 0.6-1.8) for bilateral low vision and 0.5% (95% CI, 0.2-1.1) for bilateral blindness, and the mean visual function score was 98.6. The rates of bilateral low vision and blindness increased with age, whereas visual function scores decreased with age, even after adjusting for gender and education. Cataract accounted for 58.8% of bilateral low vision, 20.0% of bilateral blindness, and 52.0% of poor visual function (score<90). Glaucoma contributed to 60.0% of bilateral blindness. CONCLUSION: The age- and gender-adjusted rates of low vision and blindness were 1.1% and 0.5%, respectively. Glaucoma is a leading cause of blindness in Singaporean Chinese adults, in addition to well-recognized causes in the rest of Asia such as cataract.     

Age-specific changes in the prevalence of best-corrected visual impairment in an italian population

PURPOSE: To investigate changes in the prevalence of visual impairment in an Italian population from 1988 to 2000. METHODS: Standardized ophthalmologic examinations were administered to citizens of Ponza, Italy aged 40-87 years in 1988 and 2000. Visual Acuity (VA) was measured using a standard logarithmic chart. Visual fields (VF) were tested in all subjects with diagnosed or suspected glaucoma or hereditary degenerative retinopathy. Visual impairment was classified as blindness (VA > 1.3 LogMAR or VF < 10 degrees around central fixation) or low vision (VA > 0.5 to 1.3 LogMAR or VF < 20 degrees to 10 degrees) according to WHO criteria. RESULTS: The prevalence of binocular total visual impairments decreased significantly among 64-75 year-olds (from 6.7% to 2.6%, p = 0.045), and almost significantly among 40-51 year-olds (from 2.4%, 95% CI 1.1-5.3, to 0.0%, 95% CI 0.0-1.3). By 2000, visual impairment was no longer significantly associated with female gender, and age 64-75 years; the mean age of subjects with vision-impairing cataract, diabetic retinopathy, or age-related macular degeneration had risen significantly. CONCLUSIONS: A decline in the prevalence of visual impairment, particularly in cataract-associated visual impairment was found in the middle-aged groups. The progression of age-related eye diseases seems to have slowed in this population possibly due to improvements in the life expectancy and socio-economic conditions.     

Prevalence of Childhood Blindness and Ocular Morbidity in a Rural Pediatric Population in Southern India: The Pavagada Pediatric Eye Disease Study-1

Purpose: To determine the prevalence of childhood blindness and ocular morbidity in a rural pediatric population in South India.

Methods: A population-based, cross-sectional survey of children was conducted in three phases in Pavagada and Madhugiri taluks (subdivisions) of Tumkur district in the state of Karnataka, India. In the first phase, trained fieldworkers screened 23,100 children. In the second phase, children with eye diseases were referred to the peripheral hospital to be examined by a general ophthalmologist. In the third phase, children with major eye diseases were examined by a pediatric ophthalmologist.

Results: The prevalence of ocular morbidity was 2.66% (95% confidence interval, CI, 2.46–2.87%). The most commonly observed ocular morbidity was Bitot spots (1%) followed by refractive error (0.6%). In total, 18 children were blind and the prevalence of childhood blindness (best-corrected visual acuity <3/60) was 0.08% (95% CI 0.04–0.11%); 8 (44.44%) had retinal blindness, 5 (27.76%) had lens-related blindness, 2 (11.11%) had bilateral microphthalmos, 1 (5.56%) was blind due to anterior staphyloma in the right eye and anophthalmos in the left eye, 1 (5.56%) had bilateral uveal coloboma and 1 (5.56%) had cortical visual impairment.

Conclusions: Nearly half of the blindness in the population was due to unavoidable causes (retinal). In addition to providing eye care services, an appropriate service delivery model would include the provision of rehabilitative and low vision services and implementation of genetic studies to understand the causes and increase awareness of inherited eye diseases.     

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.     

Pseudoexfoliation in southern India: the Andhra Pradesh Eye Disease Study

PURPOSE: To report the prevalence of pseudoexfoliation (PXF) and its associations with ocular diseases in a south Indian population. METHODS: This was a population-based, cross-sectional epidemiologic study in the south Indian state of Andhra Pradesh (AP). A total of 10,293 subjects of all ages from one urban and three rural areas representative of the population of AP were interviewed and underwent a comprehensive ophthalmic evaluation. PXF was diagnosed on slit lamp biomicroscopy by the presence of white dandruff-like material in the pupillary margin, on the trabecular meshwork, and/or on the anterior lens capsule of one or both eyes. RESULTS: The age-gender-area-adjusted overall prevalence of PXF was 0.69% (95% CI: 0.53-0.86). The prevalence of PXF increased with increasing age: 3.01% (95% CI: 2.45-3.80), in those 40 years of age or older, and 6.28% (95% CI: 4.80-7.76), in those 60 years of age or older. The prevalence of PXF was significantly higher among people whose occupation involved outdoor activities (adjusted odds ratio [OR], 2.14; 95% CI: 1.10-4.16). After adjustment for age, the prevalence of PXF was significantly higher in those with nuclear cataract (adjusted OR, 2.00; 95% CI: 1.13-3.54). PXF was significantly associated with blindness (adjusted OR, 2.19; 95% CI: 1.16-4.13). Fifteen (20.5%; 95% CI: 11.20-29.80) of those with PXF were blind, with age-adjusted relative risk (RR) = 4.25 (95% CI: 4.01-4.51). Unilateral blindness (41.2%; 95% CI: 29.81-52.39) and visual impairment (45.21%; 95% CI: 34.29-57.13) were also more common with PXF. Four subjects (5.5%; 95% CI: 0.27-10.2) of those with PXF had glaucoma. The prevalence of PXF in those with glaucoma was 4.2%; (95% CI: 0.17-8.23). In general linear models, the estimated mean +/- SE of IOP with glaucoma and PXF was 24.14 +/- 1.41 mm Hg and was 18.94 +/- 0.26 mm Hg with glaucoma in the absence of PXF; the difference was statistically significant (P < 0.0001). CONCLUSIONS: The association of PXF with blindness and aging has public health implications for India. This is especially so considering the burden of cataract with aging and the association of PXF with cataract as well as complications of cataract surgery. The diagnosis of PXF may also be important in the management of glaucoma in this population.     

Vision centre helps reduce blindness and vision impairment. Proof of concept in a four-year longitudinal study in an urban area in India

Purpose:To estimate the prevalence of blindness and severe visual impairment (SVI) by using a door-to-door screening and vision center (VC) examination strategy in an urban area in western Maharashtra (Pune), India and repeat the exercise after 4 years to study its impact.Methods:Four trained community health workers measured the visual acuity and performed an external ocular examination in patients’ homes. People with vision <6/18 were requested to visit the VC for a comprehensive eye examination by an optometrist. An ophthalmologist examined people whose vision did not improve to 6/12. A home examination was done for people who did not visit the VC despite two requests. The same population was examined twice in an interval of 4 years.Results:In the study, 44,535 people in 2015–16 and 98.14% (n = 43,708) of them in 2018–19 were examined. Blindness (vision < 3/60 in better eye), and moderate-to-severe visual impairment (MSVI, vision 6/18–6/60 in better eye) were 0.26% and 1.3%, respectively, in the first cohort, and 0.16% and 1.1%, respectively, in the second cohort (P < 0.001). When the worse eye was considered, the prevalence of blindness reduced from 0.72% to 0.44%, SVI reduced from 0.1% to 0.07%, and MVI decreased from 1.7% to 1.49% between 2015 and 2019 (P < 0.001). Females (P < 0.001) and older individuals (P < 0.001) were more likely to have blindness or SVI. In the VC, 8211 people were examined in 4 years.Conclusion:The reduction of blindness and MSVI in the urban area of Pune can be partly ascribed to the presence of a VC and attendant screening in this locality.     

A population-based study on the prevalence and causes of childhood blindness and visual impairment in North India

Purpose:This was a population-based study to determine the prevalence and causes of visual impairment in children less than 16 years in Urban North India.Methods:This cross-sectional study was conducted in 40 clusters of urban Delhi. 20,955 children aged less than 16 years underwent visual acuity screening using age-appropriate visual acuity charts. Unaided visual acuity of enumerated children aged over 2 years was assessed by using Lea symbols chart in 3-5 years age group and logMAR tumbling E charts for the 6-15 years age group. For children aged 0-2 years, fixation and following to torch light was assessed. All the children with unaided visual acuity of <6/12 in any eye in age group 3–15 years and inability to follow the light in age <3 years were referred for detailed ophthalmic examination.Results:Amongst 20,955 children examined for visual acuity a total of 789 children were referred to the central clinic for detailed ophthalmic examination. Of these referred children, a total of 124 had presenting visual acuity <6/18 in the better eye. The prevalence of visual impairment (VI) was 5.92 per thousand (95% CI: 4.96-7.05). The prevalence of moderate to severe visual impairment was maximum in the age group of 11 to 15 years. The main cause of avoidable VI in these children was a refractive error (75.7%). The prevalence of blindness was 0.42 per thousand.Conclusion:Optic nerve abnormalities were the most important cause of blindness in children. Refractive error is the most important cause of visual impairment amongst children and needs to be addressed.