Variation in corneal hysteresis and central corneal thickness among black, hispanic and white subjects

Abstract

To determine whether differences in corneal hysteresis (CH) and central corneal thickness (CCT) between black, Hispanic and white subjects exist independently of one another. Retrospective, cross-sectional data were reviewed for 807 eyes of 410 patients consecutively evaluated for glaucoma. Included patients had open angles, at least one reliable 24-2 perimetric examination and no evidence of nonglaucomatous vision loss. Patients underwent CH measurement with the ocular response analyzer followed by CCT measurement and full ocular examination. Patients were asked to self-classify their race or ethnicity. Statistical analyses were performed to identify characteristics that varied between black, Hispanic and white subjects and to explain this variation. Of the 270 patients (511 eyes) included, 84 were black, 96 Hispanic and 90 white. There were no significant differences in diagnosis, sex, age, intraocular pressure or glaucoma severity between races/ethnicities (p ≥ 0.16). Blacks were found to have lower CCT (529.3 μm) and CH (8.7 mmHg) compared to Hispanics (544.7 μm, p = 0.008; 9.4 mmHg, p = 0.007) and whites (549.9 μm, p < 0.001; 9.8 mmHg, p < 0.001). On multivariable analysis, inter-racial/ethnic differences in CCT were not found to exist independent of CH (p ≥ 0.10), whereas the significant intergroup variation in CH remained after adjustment for CCT and other covariates (p ≤ 0.005). Variation in CCT between races/ethnicities does not exist independent of CH. However, significant intergroup variation in CH is present independent of CCT. This finding suggests that CH may be a preferable measurement to evaluate intergroup differences in corneal properties and their relationship to open-angle glaucoma.