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

Abstract

Purpose 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. Methods 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. Results 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. Conclusion 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. This data has not been presented at any national meetings or published elsewhere.

Novel imaging biomarkers in diabetic retinopathy and diabetic macular edema

“…With the advent of widefield OCTA and flow overlay, one can differentiate between NVE and IRMA, both of which signify an advanced stage of DR. 17,83 OCTA can identify microaneurysms, IRMAs, capillary non-perfusion area, and neovascularization even before they are appreciated clinically or on fundus photography. 84 Thompson and colleagues 85 detected microaneurysms on OCTA even before they were seen on dilated clinical examination. Although FFA has higher sensitivity than OCTA on detecting microaneurysms, studies have shown that OCTA can even detect microaneurysms, which are not picked up on FFA.…”

<p>Assessment of Diabetic Retinopathy Vascular Density Maps</p>

“…Previous studies have found decreased retinal thickness in diabetes with minimal or no DR compared with retinal thickness in non-diabetic individuals. 15,31,32 In contrast, other researchers have observed a tendency towards increased retinal thicknesses in individuals with advanced DR. 33…”

Transfer Learning for Automated OCTA Detection of Diabetic Retinopathy

“…10 OCTA allows visualization of multiple retinal layers with high resolution; thus, it is more sensitive than FA in detecting subtle vascular distortions correlated with early eye conditions. [11][12][13] The recent development of quantitative OCTA offers a unique opportunity to utilize computer-aided disease detection and artificial intelligence (AI) classification of eye conditions. Quantitative OCTA analysis has been explored for objective assessment of, for example, DR, [14][15][16][17] age-related macular degeneration (AMD), 18,19 vein occlusion, [20][21][22][23] and sickle cell retinopathy (SCR).…”

“… 10 OCTA allows visualization of multiple retinal layers with high resolution; thus, it is more sensitive than FA in detecting subtle vascular distortions correlated with early eye conditions. 11 – 13 …”