Choroidal Thickness and Its Association With Age, Axial Length, and Refractive Error in Chinese Adults

Purpose: To identify the association between the choroidal thickness (ChT) with age and axial length (AL) under different refractive errors (REs) in Chinese adults. Methods: Swept-source optical coherence tomography was used to measure ChT in 2126 right eyes of 2126 participants. The participants were classified as having pathologic myopia (PM), high myopia without PM (HM), low myopia (LM), and nonmyopia (non-M) according to their REs and META-PM (the Meta-Analysis of Pathologic Myopia) classification criteria. Results: The mean age was 52.49 ± 20.39 years (range, 18-93 years), and the mean RE was -5.27 ± 5.37 diopters (D; range, -25.5 to +7.75 D). The mean average ChT was 159.25 ± 80.75 µm and decreased in a linear relationship from non-M to PM (190.04 ± 72.64 µm to 60.99 ± 37.58 µm, P < 0.001). A significant decline in ChT was noted between 50 and 70 years (r = -0.302, P < 0.001) and less rapidly after the age of 70 years (r = -0.105, P = 0.024). No correlation was noted between age and ChT under 50 years (P = 0.260). A significantly higher association with AL was noted in the central fovea (βHM = -23.92, βLM = -23.88, βNon-M = -18.80, all P < 0.001) and parafoveal ChT (βHM = -22.87, βLM = -22.31, βNon-M = -18.61, all P < 0.001) when compared with the perifoveal region (βHM = -19.80, βLM = -18.29, βNon-M = -13.95, all P < 0.001). Within each group of PM, HM, LM, and non-M, regression analysis showed that the coefficients of age and AL with different macular regions of ChT varied significantly. Conclusions: ChT was negatively correlated with age after 50 years. The thinning of the choroid was more prominent in the center and parafoveal regions as AL increased. Varied distributions of ChT decrease associated with AL and age were noted among different refractive groups.