Cataract extraction rates among Chinese, Malays, and Indians in Singapore: a population-based analysis

OBJECTIVE: To describe the rates of cataract extraction among Chinese, Malays, and Indians in an urban population in Asia.

DESIGN: Population-based incidence study using data from a medical savings fund.

STUDY POPULATION: Chinese, Malay, and Indian residents in Singapore.

METHODS: Data on all cataract operations performed for "senile cataract" (International Classification of Diseases, Ninth Revision, Clinical Modification code 366.1) between 1991 and 1996 were retrieved from Medisave, a population-wide, government-administered medical savings fund. The Singapore census was used as a denominator to allow an estimation of age, sex, and race-specific annual rates of cataract surgery.

RESULTS: Between 1991 and 1996, 61 210 cataract operations for "senile cataract" were performed on Singapore residents, which is equivalent to an average rate of 356.4 cataract operations per 100 000 persons per year (95% confidence interval [CI], 353.6-359.2). The average rate was highest for Indians (age-sex adjusted rate of 396.5 per 100 000/year), followed by Chinese (371.2 per 100 000/year), and lowest for Malays (237.2 per 100 000/year). Women had higher rates of cataract extraction than men (age-adjusted relative risk, 1.14; 95% CI, 1.11-1.17), with this pattern consistent across the 3 racial groups. The rate of cataract extraction increased by an average of 40 operations per 100 000/year (95% CI, 28.6-52.8) between 1991 and 1996. Overall, the proportion of cataract extraction without concurrent intraocular lens implantation was low (n = 762, 1.2%), but rates still decreased by an average of 0.8 per 100 000 per year (95% CI, 0.03-1.5) during the 6 years.

CONCLUSIONS: The rate of cataract extraction in Singapore is consistent with rates seen in developed countries in the West. Racial variation in rates suggests varying predisposition to cataract development and/or threshold for cataract surgery between Chinese, Malay, and Indian populations in Singapore.