Longitudinal Analysis of Diabetic Choroidopathy in Proliferative Diabetic Retinopathy Treated with Panretinal Photocoagulation Using Widefield Swept Source OCT.

PURPOSE Widefield (WF) swept source (SS) OCT imaging was used to characterize choroidal thickness and vascularity at baseline in proliferative diabetic retinopathy (PDR) and longitudinally after panretinal photocoagulation (PRP). METHODS Patients with treatment-naive PDR were imaged at baseline and 1 week, 1 month, and 3 months after PRP. Previously validated algorithms were used to calculate mean choroidal thickness (MCT) and choroidal vascularity index (CVI) in 5 regions of 12x12mm scans. RESULTS Fourteen PDR eyes were included. Baseline MCT in PDR eyes did not differ significantly from normal eyes, but CVI measurements in PDR eyes were lower in all regions (P <0.001 to 0.008). After PRP, MCT measurements in PDR eyes were significantly lower at 1 month and 3 months in all regions (P<0.001 to 0.005) except the fovea (P=.074). CVI measurements did not change over time in any region after PRP. CONCLUSIONS The choroid in PDR eyes has a smaller CVI than in normal eyes. After PRP, the choroidal thickness decreases outside the fovea, but the CVI remains constant, which suggests that a relative decrease in choroidal vascularity persists. These WF SS-OCT results are consistent with choroidal alterations found in histopathological reports of diabetic choroidopathy.