To measure choroidal thickness (CT) in diabetic eyes and its correlation with metabolic
status and the severity of diabetic retinopathy (DR). Prospective cross-sectional
study using swept-source optical coherence tomography. CT maps of 96 treatment na
< ve eyes of 48 patients with diabetes were compared to 46 eyes of 23 healthy controls.
CT changes and their relation to diabetes, age, gender, disease duration, hypertension
(HT), hemoglobin A1c level, type and severity of DR were evaluated. A significantly
thinner choroid was measured in patients with diabetes compared to controls (p < 0.009).
In the diabetic group age, gender, disease duration and HT were significantly correlated
with CT in univariable regression models (p < 0.05). In multivariable analysis, the
duration of diabetes significantly negatively correlated with CT (p = 0.02). According
to analysis of variance, there was a significant difference among means of CT in different
stages of DR (p = 0.002), with thinner CT in cases with more advanced DR. In a multivariable
predictive model, thinner CT was associated with an increased risk for the presence
of DR (p = 0.02). Diabetes mellitus itself and the severity of DR affect CT significantly,
even after adjusting for the effects of confounding systemic factors. Disease duration
seems to be associated with a reduction of choroidal thickness. Decreased CT proved
to be correlated with the severity of DR.