Early Sign of Retinal Neovascularization Evolution in Diabetic Retinopathy: A longitudinal OCT Angiography Study

Abstract

Purpose : To assess whether the combination of en face OCT and OCT angiography (OCTA) can capture observable, but subtle structural changes that precede clinically evident retinal neovascularization (RNV) in eyes with diabetic retinopathy (DR).

Methods : A retrospective, longitudinal study included patients with DR who had at least two visits. We obtained wide-field OCTA scans of one eyefrom each participant and generated en face OCT, en face OCTA, and cross-sectional OCTA overlaid on OCT. We identified eyes with RNV sprouts, defined as epiretinal hyperreflective materials on en face OCT with flow signals breaching of the internal limiting membrane on the cross-sectional OCTA without recognizable RNV on en face OCTA; and RNV fronds, defined as recognizable abnormal vascular structures on the en face OCTA. We examined the corresponding location from follow-up or previous visits for the presence or progression of the RNV. The main outcome measures were the characteristics and longitudinal observation of early signs of RNV.

Results : From 226 visits from 71 eyes, we identified RNV in 20 eyes with the combination of OCT and OCTA, of which 13 (65%) were photographically graded as PDR, 6 (30%) severe NPDR, and 1 (5%) moderate NPDR at the baseline. From these eyes, we identified 38 RNV sprouts and 25 RNV fronds at the baseline. RNV sprouts were frequently observed in capillary beds (66%), while only 31% of RNV fronds were from capillary beds (P = 0.0059). During the follow-up period (mean 13.1 months), 10 eyes (50%) showed progression of RNV, defined as having a new RNV lesion or developed RNV fronds from RNV sprouts. Four (11%) out of 38 RNV sprouts developed into RNV fronds with a mean interval of 7.0 months. Nineteen new RNV sprouts developed during the follow-up, while no new RNV frond was observed in a location with no previous RNV sprouts. The eyes with progression were younger (P = 0.014) and tended to be treatment naïve (P = 0.070) compared to those without progression.

Conclusions : Longitudinal observation demonstrated that a combination of OCT and OCTA can identify an earlier form of RNV before it can be clinically diagnosed.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Longitudinal development of retinal neovascularization (RNV). The baseline images showed two RNV sprouts on the optic disc (blue arrow) and the superonasal vessel (yellow arrow). Both RNV sprouts developed into RNV fronds at 10 months.