A comparison of endothelial cell count, central corneal thickness and intraocular pressure in different ethnic groups in the Western Cape, South Africa.

Purpose: To compare endothelial cell counts (ECC), central corneal thickness (CCT) and intraocular pressure (IOP) in different ethnic groups.

Methods: Between January 2019 and December 2021, we enrolled 373 patients who self-identified as native African (116), ethnically diverse (157) or of European descent (100). Mean intraocular pressure (IOP), CCT and ECC were recorded.

Results: IOP was similar between the groups (African mean IOP 15.7 ± 2.2 mmHg, ethnically diverse 15.8 ± 2.2 mmHg, European 16.0 ± 2.0 mmHg, p = 0.48). There were age differences but no gender differences between ethnic groups. Mean CCT was 503.6 ± 30.0 µm (African), 516.8 ± 30.0 µm (ethnically diverse) and 539.1 ± 34.2 µm (European) (p < 0.002 for all). Mean ECC was 2775 ± 272 cells/mm² (African), 2678 ± 233 cells/mm² (ethnically diverse) and 2639 ± 313 cells/mm² (European). These differences were significant between Africans and Europeans (p = 0.001) and Africans and ethnically diverse groups (p = 0.01).

Conclusion: ECC was highest in Africans with lowest CCT and conversely, Europeans demonstrated lowest ECC and highest CCT. Ethnically diverse participants demonstrated values between those of Africans and Europeans. We hypothesize that genomic research is required to determine if these differences have a genetic basis.