Measurement of Corneal Biomechanical Properties in Diabetes Mellitus Using the Ocular Response Analyzer and the Corvis ST.

Abstract

Hyperglycemia in diabetes mellitus (DM) might induce changes in corneal biomechanics. Therefore, biomechanical properties of the cornea were measured using the ocular response analyzer and the Corvis ST. In the study, 35 eyes of 35 diabetic patients were included. After an ophthalmological examination, measurements with the ocular response analyzer and the Corvis ST were taken. Additionally, biometry and corneal topography were performed and HbA1c values were collected. Results were compared to an age-, pachymetry- and intraocular pressure-matched group of 35 healthy subjects. Mean age (67.6 ± 10.3; 64.1 ± 8.3 years), intraocular pressure (13.4 ± 2.9; 12.8 ± 2.8 mm Hg), and central corneal thickness (556.4 ± 31.7; 548.6 ± 32.9 μm) were not significantly different between the groups (P > 0.05). In DM, the corneal hysteresis (CH) and the corneal resistance factor (CRF) were increased (CH: 10.8 ± 2 vs. 9.4 ± 1.6, P = 0.002; CRF: 10.6 ± 2.1 vs. 9.6 ± 1.5, P = 0.022). Also, most dynamic corneal response parameters showed significant differences. Beside others, A1 and A2 deflection amplitudes were increased (P < 0.001) and highest concavity and A2 time were extended (P < 0.001 and 0.007) in DM. According to current HbA1c value, DM was classified as controlled (≤7%) and poorly controlled (>7%) and significant biomechanical differences were measured between both groups. In DM, significant changes in corneal biomechanical properties were detectable. In patients, CH and CRF were increased and most dynamic corneal response parameters were different compared to healthy subjects.