Prevalence, Risk Factors and Impact of Myopic Macular Degeneration on Visual Impairment and Functioning Among Adults in Singapore

Abstract

Purpose : To determine the prevalence, risk factors and impact of myopic macular degeneration (MMD) on visual impairment and functioning among adults in Singapore.

Methods : In this population-based Singapore Epidemiology of Eye Diseases (SEED) Study, adults (40-80 years) with no history of cataract, refractive surgery or missing refraction but gradable fundus photographs were included. Eye examinations included refraction, axial length and visual acuity (VA) measurements. From fundus photographs, MMD was graded using the Meta-PM classification. The association between MMD and each risk factor was assessed using multivariable logistic regression models. Vision-specific functioning (VSF) was assessed with the VF–11 questionnaire validated using Rasch analysis.

Results : A total of 8,846 subjects were included (33.4% Malay, 33.2% Indian and 33.4% Chinese) with a mean age (± SD) of 57.4 ± 9.7 years. Low (-3.0 diopters [D] < spherical equivalent [SE] ≤ -0.5 D), moderate (-5.0 D < SE ≤ -3.0 D) and high myopia (SE ≤ -5.0 D) was present in 24.9%, 6.1% and 5.9% of subjects, respectively. The age-standardized prevalence of MMD was 4.3% (95% confidence interval [CI], 3.9-4.7%). The prevalence of MMD increased with severity of myopia (9.1%, 10.5% and 28.6%, among low, moderate and high myopes, respectively, p-trend <0.001). Of 405 subjects with MMD, 93.1% had Meta-PM category 2, and 6.9% had either Meta-PM category 3 or 4. Risk factors associated with MMD included older age (p<0.001), higher myopic SE (p<0.001), Malay ethnicity (p=0.008) and primary/lower education (p=0.006). The prevalence of MMD increased non-linearly (logistic function) with SE and age. Approximately 1 in 5 subjects with MMD had low vision or blindness in at least one eye (US definition). Subjects with patchy or macular atrophy in the better-seeing eye had worse best-corrected VA (β of 0.10; 95% CI, 0.06-0.15, p<0.001) and poorer VSF (β of -10.4; 95% CI, -19.3--1.5, p=0.02) than those without MMD after multivariate adjustments with presenting VA and other confounders.

Conclusions : The prevalence of MMD in Singapore is one of the highest worldwide and severe MMD has a substantial impact on vision loss and functioning. As MMD risks increase with older age and myopic SE, older adults with myopia should be monitored and cared for regularly.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.