Effect of diabetes mellitus on biomechanical parameters of the cornea.

PURPOSE To compare parameters of biomechanical response of the human cornea measured as corneal hysteresis (CH) and corneal resistance factor (CRF) in patients with diabetes mellitus and healthy control subjects. SETTING Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin, Israel. METHODS In the right eye of each participant, the CH, CRF, Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) were measured with the Ocular Response Analyzer. Central corneal thickness (CCT) was measured by ultrasonic pachymetry and intraocular pressure by Goldmann applanation tonometry (IOP GAT). Findings were compared between the 2 groups (control and diabetic). RESULTS Forty diabetic patients (17 women, 23 men) and 40 healthy subjects (19 women, 21 men) were prospectively recruited. The mean CH was 9.3 mm Hg +/- 1.4 (SD) and 10.7 +/- 1.6 mm Hg and the mean CRF was 9.6 +/- 1.6 mm Hg and 10.9 +/- 1.7 mm Hg in the control group and diabetic group, respectively (both P < .0001). Diabetic corneas were significantly thicker (P = .019); the mean CCT was 530.3 +/- 35.9 microm in the control group and 548.7 +/- 33.0 microm in the diabetic group. The CH and CRF remained significantly different in multivariate analysis that included CCT. There was no statistically significant difference between the 2 groups in IOPcc, IOPg, or IOP GAT measurements. CONCLUSIONS Diabetes mellitus affected biomechanical parameters of the human corneas, including increased CH, CRF, and CCT. Whether this observation has implications in the clinical management and understanding of corneal ectasia and glaucoma requires further study.