Alterations in Retinal Vascular and Oxygen Metrics in Treated and Untreated Proliferative Diabetic Retinopathy: A Case Report

Proliferative diabetic retinopathy (PDR) is a vision-threatening complication of diabetes. Panretinal photocoagulation (PRP) and anti-vascular endothelial growth factor (anti-VEGF) are approved treatment modalities aimed at regressing neovascularization. Data are lacking about abnormalities in retinal vascular and oxygen metrics before and after combination treatments. A 32-year-old Caucasian male diagnosed with PDR in the right eye was treated by a combination of PRP and multiple anti-VEGF treatments over a 12-month period. The subject underwent optical coherence tomography (OCT) angiography, Doppler OCT, and retinal oximetry before treatment and at 12 months, which was 6 months following the last treatment. Measurements of vascular metrics (vessel density [VD] and mean arterial and venous diameters [D_A, D_V]) and oxygen metrics (total retinal blood flow [TRBF], inner retinal oxygen delivery [DO₂], metabolism [MO₂], and extraction fraction [OEF]) were obtained. Both before and after treatments, VD, TRBF, MO₂, and DO₂ were below the normal lower confidence limits. Additionally, D_V and OEF were decreased after treatments. Alterations in retinal vascular and oxygen metrics were reported for the first time in untreated and treated PDR. Future studies are warranted to evaluate the clinical value of these metrics in PDR.