Abstract
Purpose :
This study investigates the application of Optical Coherence Tomography Angiography (OCTA) in monitoring treatment response of choroidal neovascularization (CNV) in neovascular age-related macular degeneration (nAMD) following intravitreal anti-vascular endothelial growth factor (VEGF) injection.
Methods :
In this prospective study, nAMD patients with fluorescein angiographic confirmed CNV who require anti-VEGF injection were included. Subjects received two OCTA scans, namely before and 4-6 weeks after the injection.
34 eyes from 32 subjects were studied between August 2020 and Dec 2021 at Grantham Hospital, Hong Kong. Correlation analysis between the interval changes on the consecutive OCTA scans, including the CNV classification type, vessel area, vessel density, morphology, border, and treatment outcome, including visual acuity (VA), central subretinal thickness (CST), is performed using SPSS Statistics.
Results :
The subjects were of mean age 75.7 (63 - 92), a male to female ratio 1:28 to 1, and have a mean visual acuity of 0.232 (0.02 - 0.7). There were 4 eyes with Type 1 CNV, 14 with Type 2, and 7 with Type 4 CNV. CNV was unidentifiable in 9 eyes.
Eyes with type 2 CNV has significantly larger CNV area in outer and choriocapillaris layer, and lower density in choriocapillaris layer. The CNV area (before treatment 3.94 mm2, after treatment 2.76 mm2, P=0.03) and density (before treatment 0.53, after treatment 0.40, P=0.02) in choriocapillaris was significantly reduced in the repeated scan.
Statistical analysis revealed significant correlations between the reduction in CNV vessel density in choriocapillaris layer and decreased CST (P=0.001); CNV vessel area in choriocapillaris layer were also significantly correlated to the improvement of VA (P=0.038).
Conclusions :
With treatment, the reduction in CST corresponds to reduction in CNV density. This can be attributed to effective anti-angiogenesis and anti-permeability actions by the anti-VEGF treatment. Reduction of CNV area with treatment corresponds to the improvement of visual acuity.
A positive correlation between CNV area and density on OCTA scans and patient's treatment outcome hints at the potential use of OCTA scans to monitor disease progression.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.