Peripapillary Choroidal Thickness in Adult Chinese: The Beijing Eye Study

PURPOSE. To measure peripapillary choroidal thickness (PPCT) and to assess its associations. METHODS. The population-based cross-sectional Beijing Eye Study 2011 included 3468 participants. Detailed medical and ophthalmic examinations were performed. We measured PPCT by spectral-domain optical coherence tomography (SD-OCT) with a 3.4-mm scan circle centered on the optic nerve head. RESULTS. Peripapillary choroidal thickness measurements were available for 3060 (88.2%) study participants with a mean age of 64.4 +/- 9.6 years (range, 50-93 years). Mean global PPCT was 134 +/- 53 mu m (range, 35-348 mu m). Peripapillary choroid was thickest in the superior region (155 +/- 60 mu m), followed by the temporal region (144 +/- 75 mu m; P < 0.001); nasal region (139 +/- 55 mu m; P < 0.001); and inferior region (110 +/- 45 mu m; P < 0.001). In multivariate analysis, thicker PPCT was associated with younger age (P < 0.001; standardized coefficient beta: -0.33; correlation coefficient B: -1.95; 95% confidence interval (CI): -2.25, -1.65); shorter axial length (P < 0.001; beta: -0.11; B: -5.39; 95% CI: -7.85, -2.93); smaller parapapillary alpha zone (P = 0.01; beta: -0.06; B: -5.46; 95% CI: -9.73, -1.19); and smaller beta zone (P < 0.001; beta: -0.14; B: -8.29; 95% CI: -11.12, -5.46); better best corrected visual acuity (logMAR; P = 0.002; beta: -0.05; B: -14.75; 95% CI: -28.59, -0.91), and higher prevalence of early age-related macular degeneration (P = 0.04; beta: 0.05; B: 9.11; 95% CI: 0.42, 17.80) and intermediate age-related macular degeneration (P = 0.001; beta: 0.08; B: 10.90; 95% CI: 4.46, 17.33). It was not significantly (all P > 0.05) associated with blood pressure, blood concentration of lipids, intraocular pressure and prevalence of glaucoma, diabetic retinopathy, and retinal vein occlusions. The decrease of PPCT with longer axial length occurred predominantly in the temporal region. CONCLUSIONS. Peripapillary choroidal thickness is thickest superiorly and thinnest inferiorly. It decreases by 2 mu m per year of life and by 5 mu m per diopter of myopia. Thinner PPCT is correlated with larger parapapillary a and b zones. The association of thinner PPCT with lower best corrected visual acuity may warrant further study.