PURPOSE. We measured scleral thickness in eyes of Chinese, and assessed interregional differences and associations with age and axial length. METHODS. Using light microscopy, we histomorphometrically measured scleral thickness at various locations in eyeballs from Chinese patients that had been enucleated due to retinoblastoma, uveal melanoma, or absolute painful glaucoma. RESULTS. The study included 281 globes from patients with a mean age of 24.8 +/- 23.1 years (range, 1-83 years) and mean axial length of 24.3 +/- 3.9 mm (range, 17.0-35.7 mm). In multivariate analysis in children aged <= 2 years, thicker posterior scleral thickness was marginally significantly associated with older age (P = 0.07; standardized correlation coefficient beta, 0.21; correlation coefficient B, 62.2; 95% confidence interval [CI], -4.3,128.8) after adjusting for shorter axial length (P = 0.01). In participants aged >= 5 years, larger posterior scleral thickness was significantly associated only with shorter axial length (P < 0.001; beta, -0.49; B, -24.1; 95% CI, -30.6, -17.6), but not with age (P = 0.93). The ratio of posterior scleral thickness to scleral thickness in the pars plana region decreased significantly with increasing axial length. The correlation coefficients were higher for the ratio of scleral thickness posterior pole/pars plana region than for posterior pole/ora serrata, posterior pole/equator, or posterior pole/midpoint posterior pole to equator. Scleral thickness measurements were not significantly (all P > 0.10) associated with adult glaucoma. CONCLUSIONS. Scleral thickness increased up to an age of 2 years, while afterwards scleral thickness was independent of age and decreased with longer axial length. Differences in the associations between the regional scleral thickness ratios and axial length suggested a scleral thinning taking place in axially elongated eyes predominantly in the posterior globe segment.