Choroidal thickness in diabetic patients without diabetic retinopathy

Purpose Compare choroidal thickness (CT) between diabetic patients without diabetic retinopathy (DR) and a non‐diabetic group. Explore how CT relates to disease duration, mean arterial pressure (MAP), glycaemia, glycosylated haemoglobin (HbA1c), intraocular pressure and ocular pulse amplitude (OPA). Methods In this cross‐sectional study, CT was assessed using SD‐OCT (Spectral Domain Optical Coherence Tomography) and enhanced depth mode at 13 different locations (subfoveal and 3 measurements 500 μ m apart in all 4 directions – nasal, temporal, superior and inferior). Linear regression models were used to analyse the data. Results 175 patients were recruited (125 diabetic patients without DR and 50 non‐diabetics patients). In diabetic patients, CT was significantly thicker than in non‐diabetic group in two locations: 1,500 μ m nasal (p = 0.036) and 1,500 μ m superior to the fovea (p = 0.021). CT was negatively associated with age (p < 0.001) in both groups, but only in the diabetic group was it positively associated to OPA (with a mean increase in thickness between 8.5 and 11.6 μ m for each increase of one OPA's unit). CT values seem to stabilize after 150 months of diabetes, with patients presenting higher glycaemia levels (>160 mg/dl) while showing no fluctuation in neither HbA1c nor MAP. Conclusions There appears to be a thickening of the choroid in diabetic patients without DR. Moreover, this tissue may be functionally different in diabetic patients, as the pattern of associations seems to differ between groups.