Influence of glycosylated hemoglobin on the choroidal thickness

The aim of the study reported here was to assess the influence of serum HbA1c levels on foveal choroidal thickness in diabetic patients.

A total of 122 eyes from 122 patients who had type 2 DM were studied in this prospective, cross-sectional study. Patients were divided into three groups: 43 patients (43 eyes) without diabetic retinopathy (NDR), 39 patients (39 eyes) with diabetic retinopathy and no macular edema (DR/ME-), 40 patients (40 eyes) with diabetic retinopathy and macular edema (DR/ME+). Central foveal thicknesses and subfoveal choroidal thicknesses were noted. Subfoveal choroidal thickness measurement was taken perpendicularly from the outer part of the retinal pigment epithelial layer to the line corresponding to the choroidal-scleral junction. Serum glycosylated hemoglobin (HbA1c) levels were evaluated.

No significant differences in age, gender, pseudophakia were observed between the groups. There was no significant difference in HbA1c value among the three diabetic groups. Mean foveal choroidal thickness was 270.09 ± 42.41 in NDR group, 243.18 ± 30.21 in DR/ME- group and 250.90 ± 40.06 in DR/ME+ group. Mean foveal choroidal thickness in NDR group was significantly different from DR/ME- group. There was no statistically significant difference between the other groups among foveal choroidal thicknesses. There was no correlation between HbA1c and foveal choroidal thickness. Multiple regression analyses of two diabetic retinopathy groups showed no significant correlation between foveal choroidal thickness and HbA1c and also no significant correlation between foveal choroidal thickness and duration of diabetes.

Serum HbA1c levels were not correlated with foveal choroidal thickness. Choroidal thickness is effected by several factors as axial length, age and systemic diseases.