Corneal Biomechanics in Patients With Diabetes Mellitus

Abstract

Purpose: : The primary objective was to compare corneal biomechanical properties in patients with diabetes mellitus and control subjects. Secondary objectives were to investigate the relationships between corneal biomechanics and glycemia, duration of diabetes, and glycosylate haemoglobin (HbA1c) blood levels.

Methods: : Thirty two eyes of 32 diabetic patients (DM) and 16 eyes of 16 age and refraction matched control subjects were included in this cross-sectional clinical study. All subjets underwent a complete ophthalmological examination including axial length (AL) and central corneal thickness (CCT) measurements. Intraocular pressure was measured by Goldmann applanation tonometry (GAT) and Dynamic Contour Tonometry (DCT). Corneal hysteresis (CH), measured by the Ocular Response Analyser (ORA, Reichert Ophthalmic Instruments), and the difference between GAT and DCT readings were used as measures of corneal biomechanics. Mann-Whitney U test, independent samples T test and multiple regression analysis were used to analyse data.

Results: : The mean age was similar between groups (DM 57.60±16.89 yrs, controls 59.62 ±18.11 yrs, p=0.065). The mean axial length was similar between groups (DM 23.18±0.81 mm, controls 23.33±0.87 mm, p=0.57). No differences between groups were found in CCT (DM 540±28 µm, controls 554±35 µm, p=0.18), in CH (DM 11.13±1.8 mmHg, controls 10.5±1.15 mmHg, p=0.16), and in GAT-DCT (DM -2.81±3.0 mmHg, controls -2.71±1.93 mmHg, p=0.89).No significant relationships have been found between glycemia, duration of diabetes, HbA1c and either CH (R²= 0.09, 0.002, and 0.1 respectively) or GAT-DCT (R²= 0.002, 0.007 and 0.0002 respectively). The lack of association was confirmed also after adjusting for the potential confounding of CCT.

Conclusions: : Corneal biomechanics seemed not to be altered by the presence of diabetes mellitus in this sample population.

Keywords: cornea: clinical science