Introduction: This study aimed to describe the morphology of age-related macular degeneration (AMD) as well as to obtain an estimate of the population-based incidence rate in Singapore.
Methods: This is a retrospective hospital-based study of AMD cases seen in 1991 and 1992 at the Singapore National Eye Centre (SNEC), a tertiary eye centre. All case notes recorded with the International Classification of Diseases, ninth revision, clinical modification code '362.5', which is 'degenerations of the macula', were retrieved and analysed. Only case notes of patients who were aged 50 years and above and with documented AMD were included in the study.
Results: There were 41 (21.8 percent) patients with drusen alone, 39 (20.7 percent) with dry AMD and 108 (57.5 percent) with exudative AMD. The morphology of the disease was similar among the Chinese and non-Chinese and there were no gender differences. A significant majority of patients with dry and exudative AMD had legal blindness at presentation (p-value is less than 0.0001). Notably, 27 (33.3 percent) patients with exudative AMD had improved vision with time. In comparison, the majority of patients with dry AMD or drusen alone tended to have the same or worsening visual acuity over time. The two-year SNEC hospital incidence rate of AMD in 1991-1992 was 0.38 percent or equivalent to 3.8 per 1,000 new cases seen at SNEC. The estimated population-based incidence rate of exudative AMD was 0.02 percent.
Conclusion: The population incidence of exudative AMD is lower but comparable to the Western population. Patients with exudative AMD tend to have poorer vision as compared to patients with geographical atrophy or drusen. The proportion of exudative AMD to geographical atrophy appears to be higher than in the West.