Corneal Endothelial Characteristics in Normal Chinese Han Children and Youngsters: A Study from the Specular Microscopy Descriptions

Abstract

Objective. To observe the morphological changes of corneal endothelial cells in healthy Chinese children and youngsters and analyze the sensitive and specificity of the endothelial assessments. Methods. 14,670 Chinese healthy volunteers enrolled were examined by specular microscopy, and the endothelial descriptive indexes: the central corneal thickness (CCT), endothelial cell density (ECD), coefficient of variation in average cell size (CV), the percentage of regular hexagonal cells (hexagonality, HEX), cell size of minimal cell ( $S_{\min }$ ), cell size of maximal cell ( $S_{\max }$ ), average cell size ( $S_{\text{avg}}$ ), and size of standard deviation of cell area ( $S_{\text{sd}}$ ) as well as sex and age were analyzed. Results. The average age of this study is $17.36\pm 7.58$  (4–30) years. There is no sex predominance: 7,260 male (49.5%) and 7,410 female (50.5%). The mean CCT, ECD, CV, HEX, $S_{\min /\max }$ , S ${}_{\text{avg}}$ , and $S_{\text{sd}}$ are $529.94\pm 31.53$ (437–644) μm, $\mathrm{3,051.28}\pm 375.49$ (2,031–4,074) cells/mm2, $28.34\pm 4.36$ (18–40) %, $61.21\pm 10.29$ (17–89) %, ( $147.79\pm 21.94$  to $678.29\pm 120.96$ ) μm2, $332.74\pm 44.62$  μm2, and $95.02\pm 23.17$  μm2, respectively. The CCTs keep consistency. The ECD decreased rate is 1.02%/year. The curve of ECD and hexagonality expresses the same linear tender. The CCT and endothelial evaluation indexes have no sex predominant ( $p>0.05$ ); the quantitative indicators: CCT, ECD, and HEX are significant negative associated with age ( $p=0.001$ or $p<0.001$ ); the variability indexes: the CV, $S_{\min }$ , $S_{\max }$ , $S_{\text{avg}}$ , and $S_{\text{sd}}$ are positive correlation ( $p<0.001$ ). The coefficients of CCT, HE, and $S_{\min }$ are -0.35, -0.59, and 1.17, respectively. Conclusions. The ECD decrease rate is 1.02%/year of the normal Chinese Han childhood to the earlier adulthood. The ages 4 to 12, 13 to 20, and 21 to 30 can be named as the childhood, puberty and adulthood from endothelial biologic identity. The HEX is the sensitivity marks for the polymorphisms while the S min is the specificity indicator CVs upon the Topcon Noncon Specular microscopy results.