Changes in choroidal thickness and corneal parameters in diabetic eyes

Purpose To evaluate the effect of diabetes mellitus on the central corneal thickness (CCT), corneal endothelial parameters (endothelial cell density (ECD), their average size (Ave), hexagonality (A6), polymegathism (CV)) and the subfoveal choroidal thickness (SFCT). To determine whether these parameters depend on the duration of diabetes and haemoglobinA1c (HbA1c) level. Methods 62 diabetic patients and 65 healthy subjects were examined using a non-contact specular microscope, A-scan ultrasound and spectral domain optical coherence tomography. The study parameters included medical history, age, axial length, SFCT, CCT, ECD, A6, CV, Ave. The duration of diabetes and HbA1 level of 2 latest tests (6 months period) were noted. Results There was equal proportion of men and women 31(50%) in the diabetes group (62 patients, 124 eyes). The mean age was 45.5(±13.4) years, duration of diabetes – 9.3(±6.6) years, HbA1c level – 9.8(±2.3)%. Diabetic retinopathy (DR) was present in 22(17.9%) eyes, macular edema - 10(8.1%). There were no differences in age, gender or axial length between the groups (p>0.05). SFCT (258.0±74.4µm) and ECD (2721.8±264.1cell/mm2) were significantly lower, CCT (566.7±35.7µm) - higher in diabetic patients than in control group (313.1±88.5µm, 2967.3±220.6cell/mm2, 550.0±56.4µm) (p 0.05). No differences in endothelial parameters between groups and no correlations between HbA1c, duration of diabetes and any of the examined parameters were found (p>0.05). Conclusion Diabetic patients have thicker corneas, lower endothelial cell density and thinner subfoveal choroid than healthy subjects.