Evaluation of the relationship between corneal biomechanic and HbA1C levels in type 2 diabetes patients

PURPOSE: To evaluate the corneal biomechanical properties due to the glycosylated hemoglobin (HbA1C) levels using the ocular response analyzer (ORA) in the patients with type 2 diabetes mellitus (DM). METHODS: ORA values were obtained from 156 eyes of subjects with type 2 DM and 74 eyes of healthy control subjects with similar age and sex. Subjects were divided into three groups: Group 1, healthy control subjects; Group 2, diabetes patients with HbA1C <7%; and Group 3, diabetes patients with HbA1C ≥7%. Corneal biomechanical parameters: corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) measurements were obtained using ORA. Ultrasound pachymetry was used for measurement of central corneal thickness (CCT). RESULTS: CH and CRF were significantly different in each of the three groups (P-values for CH respectively; Groups 1 and 2=0.008, Groups 1 and 3, and Groups 2 and 3, <0.001, and for CRF respectively; =0.002, <0.001, <0.001). CCT was significantly different between Groups 1 and 3 and Groups 2 and 3 (P<0.001) but was insignificant between Groups 1 and 2 (P=0.965). IOPcc was not different between Groups 1 and 2 (P=0.524), and Groups 2 and 3 (P=0.115), but was significantly different between Groups 1 and 3 (P=0.003). IOPg was statistically different between each of the three groups (respectively; Groups 1 and 2, P=0.015, Groups 1 and 3, and Groups 2 and 3, P<0.001). CONCLUSION: Both diabetes groups were affected in terms of corneal biomechanical properties when compared to healthy subjects, there was also a positive correlation between HbA1C level and intraocular pressure.