Swept Source OCT Angiographic Characteristics of Treatment-Naïve Nonexudative Macular Neovascularization in AMD Prior to Exudation

Abstract

Purpose : To determine if there are any characteristic changes in treatment-naïve nonexudative macular neovascularization (MNV) in age-related macular degeneration (AMD) when imaged using swept source optical coherence tomography angiography (SS-OCTA) that may be predictive of near-term exudation.

Methods : AMD patients with treatment-naive, nonexudative MNV were identified and underwent SS-OCTA imaging (PLEX® Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA) using 6X6mm and 12X12mm scans by the same technician at all visits. The patients were divided into two groups based on whether the nonexudative MNV developed exudation. If the nonexudative MNV developed exudation, then the last two visits before the visit when exudation was documented were selected for analysis. If the MNV did not develop exudation, then the two consecutive visits 6 months before their last follow-up visits were used for analysis to be sure no near-term exudation developed. MNV area, choriocapillaris (CC) flow deficits (FDs), MNV vessel area density (VAD), MNV vessel skeleton density (VSD), retinal pigment epithelial detachment (PED) volume, mean choroidal thickness (MCT), and choroid vascularity index (CVI) measurements were measured at the two visits prior to exudation. The en face area measurements of the MNV were obtained by using a previously described validated automated algorithm that detected angiographic flow within the outer retina to CC slab.

Results : Twenty-one eyes with nonexudative MNV were identified and followed. Twelve eyes did not develop exudation, while nine eyes developed exudation. There were no significant differences between the two groups in the MNV area, the percentages of surrounding CC FDs, or the rate of change in any of the measurements (all P values ≥0.052). The eyes that did develop exudation had smaller MNV-VAD (P=0.002), MNV-VSD (P=0.005), and MNV-PED volume (P=0.04) measurements at the visit prior to exudation. The CT and CVI measurements over the final two visits were not significantly different between the two groups (all P values >0.19).

Conclusions : The onset of exudation was associated with lesions with less vascularity and smaller PED volume measurements, but measurements of MNV area, CC FDs, CT, and CVI or the change in any measurements did not show statistically significant differences between the two groups over the final two visits.

This is a 2021 ARVO Annual Meeting abstract.