A study on corneal morphometric parameters among Mongolian adults

Abstract

Background: The corneal endothelium, the innermost layer of the cornea, is composed of hexagonal cells that maintain corneal transparency and provide essential nutrients to the stroma. These cells play a critical role in preserving visual acuity. Previous studies have demonstrated that endothelial cells do not regenerate, and their density progressively declines with age, accompanied by morphological alterations. Given the individual variability in corneal thickness and endothelial morphology, establishing normative reference values is crucial for diagnosing corneal diseases, planning corneal transplantation, and optimizing surgical strategies for cataract surgery. However, there is a scarcity of data regarding central corneal thickness, endothelial cell density, and cell morphology among Mongolian adults. This knowledge gap provided the rationale for the present study. Aim: To study the central corneal thickness and endothelial cell morphology in Mongolian adults. Materials and Methods: This study was conducted using an analytical cross-sectional design. A total of 198 individuals aged 20 to 79 years were randomly selected, and comprehensive ophthalmic examinations were performed. Corneal parameters—including central corneal thickness, endothelial cell density, mean cell area, coefÏcient of variation of cell size, and the percentage of hexagonal cells—were quantitatively assessed using a non-contact specular microscope. Ethical approval was obtained from the Research Ethics Committee of the Mongolian National University of Medical Sciences (Approval No. 2024/3-06), and written informed consent was obtained from all participants prior to enrollment. Results: The mean age of the study participants was 48.4±14.5 years, with 48.9% (n=97) being male and 51.1% (n=101) female. In the central cornea, the mean endothelial cell density (ECD) was 2857.14±291.49 cells/mm², the mean central corneal thickness (CCT) was 526.25±33.67 µm, the mean cell area was 335.11±37.82 µm², the percentage of hexagonal cells was 64.81±3.94%, and the coefÏcient of variation (CV) in cell size was 0.31±0.04. With increasing age, both ECD and the percentage of hexagonal cells showed a statistically significant decline, while the mean cell area and CV demonstrated a significant inverse correlation (P=0.0001). No statistically significant differences were observed in corneal thickness or endothelial morphometric parameters between the right and left eyes or between sexes. Among the Mongolian adults, the endothelial cell density decreases by approximately 0.3% annually (r=0.2107, p<0.0001). Conclusions: 1. The mean central corneal thickness (CCT) in adult Mongolian individuals was 526.25±33.67 μm, which is comparable to reported averages from other populations. However, the mean endothelial cell density (ECD) was relatively higher, measured at 2857.14±291.49 cells/mm². 2. With advancing age, a progressive decline in central endothelial cell density and the proportion of hexagonal cells was observed, whereas the coefÏcient of variation (CV) in cell size and the mean cell area showed a corresponding increase.