Quantitative evaluation of morphological changes in anti-VEGF treated choroidal neovascularization due to age related macular degeneration using optical coherence tomography angiography.

Abstract

Purpose : The purpose of this study was to determine if clinical response to anti-VEGF intravitreal injection therapy correlated to quantitative changes of CNV area and vascularity in OCTA.

Methods : 10 eyes of 10 patients (4 males, 6 females, mean age 75,1 y. o) with CNV were enrolled in the study. The inclusion criteria were presence of CNV confirmed with OCT, OCTA and FA in patients with initially active disease. A comprehensive ophthalmological exam was performed and OCTA was performed with Heidelberg Spectralis or Optovue using high resolution scans during the initial disease activity. The follow-up scan was performed after the successful response, i.e. at the presence of major reduction of sub- or intraretinal fluid or disappearance. CNV area was manually delineated and measured using Image J (area of selection in square milimeters). The CNV vascularity was measured using AngioTool by determining area of the vessels and was determined as a percentage of area occupied by vessels inside the explant area. Paired analysis was performed to compare the parameters at baseline and at the follow-up. The images were overlaid using the opencv(CV2) package in Python to look for morphological changes before and after the treatment.

Results : Analysis of vascularity of the lesion showed a decrease from 34% to 23% (p=0.002). The pre-and post-treatment mean CNV area was 74.26 before versus 66.57 square milimeters after treatment (p=0.1621). The analysis of overlaid images showed that in most cases morphology of the vessels changes with narrowing of the vessels and fewer vessels after the injection.

Conclusions : We found that the CNV vessel percentage area correlates with clinical response to anti-VEGF, and it decreases significantly after the successful treatment. Treatment effect may thus be due to reduced lumen and permeability. The reduction in vascular percentage may be due to reduction in vascular lumen and number of vessels. OCTA thanks to its ability to image the dynamics of neovascular changes may be a useful additional method in determining the optimal intervals of anti-VEGF injection.

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