Abstract
Purpose: :
To investigate the biomechanical properties and other ocular parameters in healthy eyes as a function of the race of the participant.
Methods: :
A total of 77 subjects were recruited and stratified into five racial/ethnic groups based on self-identification: Asian (n=14), South Asian (n=15), Black (n=18), Hispanic (n=15), and Caucasian (n=15). Subjects underwent each of the following measurements in one eye: Goldmann Aplanation Tonometry (GAT), PASCAL Dynamic Contour Tonometry (DCT), Reichert Ocular Response Analyzer (ORA), Schiotz Tonometry, Axial Length, Keratometry, and Pachymetry. Individuals who had a history of ocular surgery or ocular pathology treated with topical eyedrops, diabetes, or hypertension were excluded from the study. All non-contact measurements were performed first, followed by the contact measurements in a randomized order. ANOVA was performed with a Bonferroni correction for repeated comparisons.
Results: :
The height of the first infrared peak of the ORA signal, Peak 1, was significantly higher (p<.0001) in Hispanics than all other racial groups. No other significant differences were noted in the ORA signal or in the biomechanical parameters of corneal hysteresis and corneal resistance factor between racial groups. Additionally, Hispanic corneas were significantly flatter (p=0.0054) than Caucasian corneas in this population. No other corneal curvature differences between races were found. Mean axial length of Asians (25.08mm+1.160) was significantly higher (p=.0491) than that of Caucasians (23.85mm+0.9989). No other axial length differences were found. When compared to Caucasians values, Schiotz tonometry with a 5g load showed significant differences in Asians (p=.0004), Blacks (p=.0051), Hispanics (p=.0029) and South Asians (p=.0070) values. None of the non-Caucasian groups were different from each other. With a 7g load, Schiotz tonometry measurements significantly differed between Caucasians and Asians (p=.0073), as well as Caucasians and South Asians (p=.0050). No significant differences were identified between racial groups using a 10g load with the Schiotz tonometer. Furthermore, no significant differences were found with DCT IOP, ORA IOPcc, GAT, or pachymetry between racial groups.
Keywords: cornea: clinical science • clinical (human) or epidemiologic studies: prevalence/incidence