Clinical utility of navigated ultrawide field optical coherence tomography in differentiating nonproliferative and proliferative diabetic retinopathy

Abstract

Purpose : To evaluate whether ultrawide field integrated SS-OCT can be used to distinguish between nonproliferative features such as intraretinal microvascular abnormalities(IRMA) from proliferative features such new vessels(NV).

Methods : This cross-sectional study evaluated patients with severe nonproliferative diabetic retinopathy (NPDR)who presented to a single MD retina clinic (MA) at the Beetham Eye Institute from July 1 to Dec 15, 2021.Patients were imaged on a device combining UWF color imaging(CI) and navigated SS-OCT (Silverstone,Optos). A 12-mm raster protocol (macula, optic nerve head and superotemporal to inferotemporal arcades) and mid-peripheral volume scans in all four quadrants were performed. Any area with suspected NV or large IRMA (>8A) were imaged. A clinical assessment and UWF stereoscopic CI grading by the MD providing clinical care was performed. Lesions were considered to be NV if they were seen to break through the internal limiting membrane on SS-OCT.

Results : The study included 14 eyes of 8 patients with diabetes mellitus. 25.0 % were female, mean age of 51.5±7.97 years,42.9% had type 1 DM, with a mean duration of 23.4±9.3 years, and an average A1c of 8.4±1.9%. A total of 24 IRMAs were suspicious for NVE on UWF-CI grading. 21 (87.5%) were captured on navigated OCT with 3(12.5%) located outside the imaged area. Among IRMA imaged(N=21), evaluation of SS-OCT image determined that 5 lesions(23.8 %) were NVE and not IRMA. Of these, 3 were flat and confined to the posterior hyaloid face and 3 had forward extension and vitreous invasion. In one eye an additional NVE was detected that was not previously flagged as a suspicious NVE. The NVE identified resulted in a change in the DR grading from severe NPDR to PDR in 4 eyes(21.4%).

Conclusions : This pilot study explores the possible clinical utility of navigated SS-OCT in assessment of IRMA in subjects with severe NPDR. Initial findings suggest a substantial portion of eyes may have undetected proliferative disease that can be identified using this modality and thus further investigation is warranted. Future studies will include a larger cohort of patients to compare between OCT/UWF-CI grading, UWF-CI grading alone and UWF-FA to establish whether this approach provides benefit to existing imaging modalities with regard to IRMA as well as all other important diabetic retinopathy lesions.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.