The epidemiology of myopia in Hong Kong.

INTRODUCTION The prevalence of myopia amongst the Chinese has escalated in recent decades. While this refractive error was previously a little more than an inconvenience and a source of unwanted expense to the affected individuals, it is now sufficiently prevalent to warrant national concern. Myopia is also a major cause of low vision. This review aims to provide information on the prevalence of myopia in the Chinese community in Hong Kong. MATERIALS AND METHODS Based on a number of studies carried out mainly at the Centre for Myopia Research in The Hong Kong Polytechnic University, myopia in the Chinese community in Hong Kong is described. RESULTS Infants in Hong Kong appear to have refractive errors similar to infants of European descent; however, by the age of 7 years myopia is already prevalent. The annual incidence of myopia thereafter averages 11% to 12%; by the age of 17 years more than 70% are myopic, and this prevalence is greater than in people of European descent. In Hong Kong, myopia is much less prevalent in the older generation. CONCLUSION The increase in prevalence of myopia over a short period of time is postulated to be due to environmental factors. Children of Chinese descent have a susceptibility to environmental factors which cause myopia.