Prevalence and Causes of Visual Impairment and Blindness in an Urban Chinese Population: The Singapore Chinese Eye Study

Abstract

Purpose : To determine the prevalence and causes of blindness and visual impairment in the Singapore Chinese population and compare with a previous population-based study (the Tanjong Pagar Survey) conducted earlier in the 90s.

Methods : In a population-based survey of 4605 eligible individuals living in the southwestern part of Singapore, 3353 Chinese adults 40 years or older (72.8% response rate) participated and underwent comprehensive, standardized examinations which included measurement of presenting visual acuity (PVA) and best-corrected visual acuity (BCVA). Visual impairment (<20/40 to >20/200, better eye) and blindness (≤ 20/200, better eye) were defined according to US definition. Singapore Census of Population 2010 was used to calculate age-standardized prevalence. Primary causes and factors associated with visual impairment and blindness were also determined.

Results : Based on PVA, the age-standardized prevalence was 17.7% for visual impairment and 0.6% for blindness. Based on BCVA, the age-standardized prevalence was 3.4% for visual impairment and 0.2% for blindness. These rates were slightly lower than the Tanjong Pagar Survey (3.8% and 0.3% for visual impairment and blindness respectively based on BCVA), but the difference was not statistically significant. Cataract was the principal cause of best-corrected blindness (50.0%) and best-corrected visual impairment (69.8%), followed by age-related macular degeneration (25.0%, 0.9%) and diabetic retinopathy (12.5%, 3.4%). In the Tanjong Pagar Survey, while cataract was the leading cause of low vision (58.8%), glaucoma was the main cause of blindness (60.0%), followed by cataract (20.0%) and age related macular degeneration (20.0%). Factors associated with visual impairment in this study included older age (P<0.001, odds ratio (OR) 2.25, 95% confidence interval (CI) 1.94 to 2.61), lower income (P<0.001, OR 2.49, 95% CI 1.53 to 4.06), lower education (P<0.001, OR 2.81, 95% CI 1.84 to 4.27), and smaller housing (P=0.003, OR 2.25, 95% CI 1.43 to 5.55).

Conclusions : Although the prevalence of visual impairment and blindness in Chinese residing in Singapore was low, the estimates were similar to those from a previous study in Singapore conducted in the 1990s. Cataract is the current leading cause of blindness. This suggests the need for prioritizing eye care surgical services to reduce blindness in the community.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.