Changes in choroidal and retinal thickness assessed by optical coherence tomography in type 2 diabetes mellitus patients with moderate diabetic retinopathy

Purpose: To study choroidal thickness (CT) in type 2 diabetes mellitus (DM2) patients with moderate diabetic retinopathy (DR) without diabetic macular edema (DME) and to correlate with changes in retinal thickness (RT) with swept source OCT (SS‐OCT)) compared to healthy subjects. Methods: Fifty‐four DM2 patients with moderate DR without DME and 73 age‐matched healthy subjects were evaluated using SS‐OCT to measure changes in total RT and the CT in the nine areas of the Early Treatment Diabetic Retinopathy Study (ETDRS) macular grid. Results: The mean ages were 64.06 ± 11.98 years and 60.79 ± 8.62 years in the diabetic and control groups, respectively. Visual acuity (VA) with ETDRS 100% was lower in the DM2 patients (p 0.05) in any ETDRS area. There was a significant negative correlation between RT and age in all of the external ETDRS areas and a positive significant correlation in the central area for DM2 group. There was also a negative significant correlation between CT and age in all ETDRS areas except for the inferior inner area. In the DM2 group, a negative correlation was observed between RT and CT in the central area (p = 0.039) and in both horizontal parafoveal areas (temporal inner: p = 0.028, central: p = 0.039 and nasal inner: p = 0.003). Conclusions: DM2 patients with moderate DR have no changes in CT. CT and RT decrease with age and show a negative correlation with RT in the central and horizontal parafoveal areas of the ETDRS grid.