Macular ganglion cell complex layer thickness measured with spectral-domain OCT in a large population-based cohort study

Abstract Purpose To establish the normal GCC thickness profile in the general population using SD-OCT in different macular sectors. Determining the systemic and ophthalmic factors associated with GCC thickness and further identifying the potential risk factors were the secondary objectives. Methods Participants in the population-based cohort study had to be at least thirty years old. Every participant had a routine ophthalmological examination. Using SD-OCT, the GCC thickness was determined. To assess the relationship between GCC thickness and systemic and ocular characteristics, mixed linear models were used. R V.4.1.1 was the statistical analysis program utilized. Results Two thousand four hundred ninety subjects, average age 56.60 ± 10.39 years, were collected in this analysis. GCC average thickness measured was 95.57 ± 7.47 μm. The GCC thickness of the superior (95.46 ± 7.87 μm) was the thinnest, and the inferior subfield (95.68 ± 7.66 μm) was thickest. In the multivariate regression analysis, a thinner GCC was majorly linked to being older ( P < 0.001), current smoking ( P < 0.001), no diabetes ( P = 0.014), and a larger vertical cup disc ratio (VCDR) ( P < 0.001). When the data was divided by age, a thinner GCC was also connected to female ( P < 0.001), current smoking ( P = 0.006), having high systolic blood pressure (SBP) ( P = 0.002), lower low-density lipoprotein (LDL) ( P = 0.002), higher triglycerides (TG) ( P = 0.029), higher best corrected visual acuity (BCVA) ( P < 0.001), and a larger vertical cup disc ratio (VCDR) ( P = 0.002). Stratified by axial length (AL), a thinner GCC was associated with advanced age ( P < 0.001), female ( P = 0.005), and a larger VCDR ( P = 0.001). Conclusions Our study provides benchmarks for GCC thickness, distribution, and linked ocular and systemic factors among middle-aged individuals in rural China, emphasizing the strong correlation between GCC thickness and multiple ocular and systemic variables. Additionally, our findings underscore the importance of establishing global normative databases to address ethnic variations in GCC thickness and the distinctiveness of related ocular and systemic factors.