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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° 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. [Copyright &y& Elsevier]

Angle-closure glaucoma is an aggressive condition that causes millions to become blind worldwide. This review explores the use of prophylactic laser peripheral iridotomy (PI) in patients classified as primary angle-closure suspects (PACS), and additionally, the use of clear lens exchange as a primary treatment option in established angle-closure disease with or without glaucoma. As PI has a strong prophylactic effect in fellow eyes of patients who have had an acute attack, its use has been widely adopted in those patients classified as PACS, but with limited evidence to support this. A large randomised trial conducted in China has demonstrated that although PI reduces the risk of incident angle-closure disease, the incidence of disease that would threaten vision was much lower than anticipated. This suggests that the benefit of prophylactic PI is very limited. Health services data shows an association between rising cataract surgical rates and of decreasing rates of acute angle-closure. Age-related growth of the lens is a major component of angle-closure disease. Several studies have shown that clear lens extraction (CLE) effectively lowers IOP in angle-closure. The use of CLE as a primary treatment option has been tested against LPI in the EAGLE study, a large RCT that enroled people with angle-closure and an IOP > 30 mmHg, and those with angle-closure glaucoma. The trial showed CLE to be superior to PI both for IOP control and patient reported quality of life. On these grounds, CLE should be considered for first-line treatment of more advanced angle-closure disease.