Abstract
Purpose: :
To describe the prevalence of and risk factors for age-related macular degeneration (AMD) in a multi-ethnic Asian cohort of Chinese, Malay and Indian persons.
Methods: :
A population-based study comprising 3,878 persons of Chinese, Malay and Indian ethnicities, aged at least 21 years and older, residing in Singapore were included. Participants underwent comprehensive systemic and ocular examination, retinal photography and laboratory investigations. Early and late AMD signs were graded from retinal photographs at a central reading centre using the modified Wisconsin AMD scale. Auto-refraction, followed by subjective refraction was performed to obtain spherical equivalent refraction (SER) in diopters, with emmetropia defined as SER -0.5D to +0.5D, hyperopia as > 0.5D, myopia as <-0.5D. The association between various risk factors and the prevalence of AMD was analyzed.
Results: :
Of the 3,878 participants, early AMD was present in 212 subjects and late AMD in 8 subjects, giving an age-standardized prevalence of 4.6% (95% CI 3.9 - 5.5%) and 0.18% (95% CI 0.08 - 0.7%) respectively. Prevalence of any AMD was highest in Malays (5.8%), followed by Chinese (4.8%) and then Indians (3.3%), although differences were not statistically significant. Prevalence increased with age and was higher in men than women. Of range of risk factors evaluated, only hyperopic refractive error was a significant risk factor for AMD (OR 1.87 , 95% CI 1.29, 2.72, p=0.001, compared to myopia), after adjusting for age, gender, race, current smoking and socioeconomic status. Each diopter increase in SER was associated with an 1.16-fold increased risk of early AMD (OR 1.16, CI 1.08, 1.25, p<0.001)
Conclusions: :
The prevalence of AMD was comparable to Western studies such as the Blue Mountains Eye Study and not statistically different between the three major Asian racial groups. Hyperopic refractive error is a risk factor of AMD in Asian eyes.
Keywords: age-related macular degeneration • hyperopia