Optical coherence tomography angiography characteristics in diabetic patients without clinical diabetic retinopathy

The purpose of this study is to measure optical coherence tomography angiography (OCTA)-defined retinal vascular and choriocapillaris parameters in diabetic patients without clinically evident diabetic retinopathy.

Retrospective case series of eyes in patients with a documented history of either type 1 or type 2 diabetes mellitus without any clinical signs of diabetic retinopathy seen at the Vanderbilt Eye Institute. All eyes underwent dilated funduscopic examination along with OCTA. OCTA analytics were performed to calculate vessel density, flow area, and foveal avascular zone size.

Thirty-seven eyes of 20 patients were included in the analysis. The mean glycated hemoglobin A1c of the 20 patients was 7.2%. All patients underwent dilated funduscopic examination by a fellowship-trained retina specialist. No patients had any overt retinopathy on clinical examination. Fifteen eyes had vascular abnormalities (microaneurysms) present on OCTA. Patients with microaneurysms and patients without microaneurysms were compared. Vessel density of the 6 × 6 mm macular cube images was significantly increased in patients with microaneurysms compared with patients without microaneurysms. There were no other significant differences in OCTA characteristics.

OCTA can detect microvascular changes not otherwise noted on dilated clinical examination. These pre-clinical findings may facilitate earlier intervention for improved glycemic control and prevention of the onset of clinical retinopathy.