Early detection of choriodal neovascularization with OCT Angiography

Abstract

Purpose : To evaluate if semi-annual optical coherence tomography angiography (OCTA) can detect nonexudative choroidal neovascularization (CNV) in eyes with intermediate non-neovascular age-related macular degeneration (iAMD) and help stratify risk for developing exudative CNV.

Methods : Inclusion criteria for this longitudinal observational study required iAMD in the study eye, along with exudative neovascular AMD in the fellow eye. Patients were examined at baseline, and at six-month intervals. Clinical examination and 3X3 mm OCT angiograms (AngioVue, Optovue, Inc) were routinely obtained and fluorescein angiography (FA) if indicated. Conversion to exudative CNV required at least one of the following: intra- or sub-retinal fluid on structural OCT, hemorrhage on examination, or leakage with fluorescein angiography. OCT data were exported for custom processing. Blinded graders identified CNV as vascular networks in the outer retinal slab on both en face and cross-sectional OCT.

Results : Forty-nine eyes were enrolled. Forty eyes met image quality criteria and had complete follow-up for at least 18 months. Of these 40, OCTA detected non-exudative CNV in 5 eyes. Three of these eyes (60%) subsequently developed exudation 1, 2, and 5 months later (Fig. 1); one eye remained dormant for 25 months; and one eye was lost to subsequent follow-up. Four eyes developed exudative CNV despite negative OCTA scans at the previous regular visit 2, 3, 4, and 5 months previously. For eyes that did not have nonexudative CNV on regularly scheduled OCTA, the risk for developing exudative CNV within the subsequent 6 months was 3.8%.

Conclusions : OCTA could detect nonexudative CNV in eyes with iAMD. Eyes with nonexudative are at higher risk for developing exudative CNV within the subsequent 6 months and should be followed closely, initially with monthly visits. Regular semi-annual OCTA of eyes with iAMD may be useful to stratify the risk for developing exudative CNV.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Figure 1. Top row: OCT angiogram of nonexudative choroidal neovascularization (CNV) one month prior to development of exudative CNV. Inner retinal OCT angiogram (A). CNV present on outer retinal slab (B - blue circle) and cross-sectional OCTA (C - yellow). Bottom row: Clinical findings of exudative CNV. Color fundus photo (D) showing hemorrhage and early (E) and late (F) angiogram showing leakage from CNV.