Corneal biomechanical characteristics in patients with diabetes mellitus

PURPOSE To compare the corneal biomechanical properties in eyes of patients with diabetes mellitus and in those of subjects without diabetes mellitus SETTING Hospital eye clinic DESIGN Comparative case series METHODS Corneal hysteresis (CH) and corneal response factor (CRF) were measured in diabetic patients and nondiabetic subjects using the Ocular Response Analyzer Central corneal thickness (CCT) and intraocular pressure (IOP) were also measured Differences in corneal biomechanical properties were determined using a 1-way analysis of variance Interassociations between ocular and diabetic parameters were also evaluated RESULTS Sixty-one eyes of 61 diabetic patients and 123 eyes of 123 nondiabetic subjects were evaluated The CRF was significantly greater in the eyes of diabetic patients (mean difference 1 09 mm Hg, 95% confidence interval [Cl], 049-1 69, P = 001) There were no significant differences in CCT or CH between groups (CH mean difference, 0 38 mm Hg, 95% Cl 0 21 to 0 97 mm Hg, P = 21 CCT mean difference, 0 13 urn, 95% Cl, 10 6 to 10 8 pin P = 98) Corneal hysteresis and CRF were weakly correlated with blood glucose concentration (slopes CH 0 28 95% Cl, 0 03-0 50, P = 03, CRE 0 27, 95% CI 0 02-0 49, P = 04) In a multiple regression analysis, the effects of blood glucose concentration were reduced and age and CCT became significant predictors of CH and CRF CONCLUSIONS The eyes in diabetic patients displayed altered corneal biomechanics that may be related to blood glucose concentration Further studies are required to establish the effects of long-term poor glucose control on corneal biomechanical properties and how this might affect the diabetic patient's response to refractive surgery procedures