Six-Year Changes in Myopic Macular Degeneration in Adults of the Singapore Epidemiology of Eye Diseases Study

Abstract

Purpose : To examine the person-specific cumulative 6-year incidence and progression of myopic macular degeneration (MMD) and associated risk factors in Singapore.

Methods : We analysed data from phakic adults who attended the baseline (aged ≥40 years, 2004-2011) and 6-year follow-up (2011-2017) visits of a population-based longitudinal study (Singapore Epidemiology of Eye Diseases study). Eye examinations, including subjective refraction and axial length (AL) were done. MMD was graded using the META-PM classification from fundus photographs. Incidence of MMD was defined as development of MMD (Meta-PM category 2, 3 or 4) during follow up in those without MMD at baseline and progression of MMD as worsening of MMD in those with pre-existing MMD.

Results : In 8,716 phakic persons at baseline, 6,080 (69.8%) were re-examined. Of these, 6,030 (99.2%) had gradable fundus photographs and were analysed. Of 6030, 35.8% had myopia (spherical equivalent [SE] ≤-0.5 diopters [D]) and 6.4% had high myopia (SE ≤-5.0 D), respectively, with 2,009 at risk of MMD development. Mean baseline age (±SD) was 56.1±8.7 years (28.9% Malays, 32.1% Indians and 39.0% Chinese).

The 6-year incidence of MMD was 1.7% (95% confidence interval [CI], 1.2-2.3%). Of the 35 new MMD cases (42 eyes), 33 (40 eyes), 2 (2 eyes) and 1 (1 eye) had incident diffuse chorioretinal atrophy, patchy chorioretinal atrophy and lacquer cracks, respectively.

Among 202 persons with MMD at baseline, the 6-year progression of MMD was 17.3% (95% CI, 12.1-22.6%) and stable MMD was seen in 167 (82.7%). Of 35 persons (49 eyes) with MMD progression, 4 (6 eyes) progressed from Meta-PM category 2 to 3 with new patchy chorioretinal atrophy; 24 (35 eyes) had enlargement of existing diffuse chorioretinal atrophy; 7 (7 eyes) had enlargement of existing patchy chorioretinal atrophy; 4 (4 eyes) had widening lacquer cracks; and 3 (5 eyes) had new lacquer cracks.

Having tessellated fundus at baseline predicted MMD development at 6 years (P<0.001). Older age (P<0.001), worse SE (P=0.005) and longer AL (P=0.002) was associated with MMD incidence. Having peripapillary intrachoroidal cavitation (P=0.004), worse SE (P=0.03) and longer AL (P=0.009) was associated with MMD progression.

Conclusions : In the 6-year period, MMD was stable in majority of older adults in Singapore, with a low incidence of MMD (1.7%) and relatively low progression (17.3%) in those with existing MMD.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.