Comparison of corneal biomechanical properties between healthy blacks and whites using the Ocular Response Analyzer

Purpose: To analyze and compare corneal biomechanical properties in healthy black and white subjects using the Ocular Response Analyzer (ORA) and to evaluate their relationship with other ocular parameters.

Design: Observational cross-sectional study.

Methods: One hundred eighty one eyes (46 in blacks, 135 in whites) of 119 patients (37 blacks, 82 whites) were recruited from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS) and from the African Descent and Glaucoma Evaluation Study (ADAGES) at the University of California, San Diego. Corneal curvature, axial length, central corneal thickness (CCT), corneal hysteresis (CH), and corneal resistance factor (CRF) were obtained from all participants. Univariable and multivariable regression analyses were used to evaluate the associations between ORA measurements and age, CCT, axial length, corneal curvature, and race.

Results: Black subjects had significantly lower values of CH (9.7 mm Hg vs 10.4 mm Hg; P = .033), CRF (9.84 mm Hg vs 10.70 mm Hg; P = .028), and CCT (534 mum vs 562 mum; P = .001) compared to white subjects. A significant relationship was found between CH and CCT (R(2) = 0.25; P < .001) and between CRF and CCT (R(2) = 0.42; P < .001). After adjusting for CCT, age, axial length, and corneal curvature, the difference between blacks and whites in CH (P = .077) and CRF (P = .621) measurements lost statistical significance.

Conclusion: Black subjects tended to have lower measurements of corneal hysteresis compared to white subjects; however, this was largely explained by differences in corneal thickness. Therefore, it is unlikely that CH would have an independent effect in explaining differences in susceptibility of disease between these 2 racial groups.