Profiles of Ganglion Cell-Inner Plexiform Layer Thickness in a Multi-ethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Abstract Purpose To examine the normative profile and determinants of macular ganglion cell-inner plexiform layer (GCIPL) thickness based on spectral-domain OCT (SD-OCT) in a non-glaucoma, multi-ethnic Asian population. Design Population-based, cross-sectional study. Participants Ethnic Chinese, Malay and Indian adults, aged ≥40 years, recruited from the Singapore Epidemiology of Eye Diseases Study. Methods All participants underwent standardized examinations. GCIPL thickness was measured using Cirrus HD-OCT (Carl Zeiss Meditec). Participants with glaucoma or poor quality scans were excluded. Eye-specific data were used. Associations of ocular and systemic factors with GCIPL thickness parameters were investigated using multivariable linear regression with generalised estimating equation models to account for correlation between both eyes. Main Outcome Measure Average, superior, and inferior hemisphere GCIPL thicknesses. Results A total of 4,464 participants (7,520 eyes) consisting of 1,625 Chinese, 1,212 Malay, and 1,627 Indian adults contributed to this analysis. Average GCIPL thickness was 82.6± 6.1μm in Chinese, 81.5± 6.8μm in Malays and 78.0± 6.9μm in Indians (P Conclusions Average and subsector GCIPL thickness profiles were significantly thinner in Indians, compared to Chinese and Malays. Our findings further highlight the need of a more refined, ethnic-specific normative database for GCIPL thickness, which may in turn improve the detection and diagnosis of glaucoma in Asians in clinics.