A quantitative approach to predict differential effects of anti-VEGF treatment on diffuse and focal leakage in patients with diabetic macular edema.

Abstract

Purpose : To use semi-automated segmentation of fluorescein angiography (FA) to determine whether anti-vascular endothelial growth factor (VEGF) treatment for diabetic macular edema (DME) differentially affects microaneurysm (MA) associated leakage, termed focal leakage, versus non-MA associated leakage, termed diffuse leakage.

Methods : We performed a retrospective study of 14 subjects treated with at least three consecutive injections of anti-VEGF agents for DME (mean 5.3 injections, range 3-9) who underwent Heidelberg FA prior to and following anti-VEGF therapy. Inclusion criteria were center involving DME and FA of adequate quality for analysis. Exclusion criteria included macular edema due to cause besides DME, concurrent treatment for DME besides anti-VEGF, macular photocoagulation within 1 year. At each time point, total leakage was automatically segmented using our previously published software (Rabbani et al. IOVS 2015). Microaneurysms were identified by an expert grader and leakage within a 100 micron radius of each MA was classified as focal leakage and automatically segmented. Remaining leakage was classified as diffuse leakage. The absolute and percent change in total, diffuse and focal leakage was calculated for each subject.

Results : Mean pretreatment total leakage was 5.20 mm² and decreased by a mean of 24.4% (mean change -1.34 mm²) following treatment. Diffuse leakage decreased by a mean of 29.5% (mean absolute change -1.34 mm²) while focal leakage increased by 4.20% (mean absolute change +0.002 mm²).

Conclusions : Anti-VEGF treatment for DME results in decreased diffuse leakage but had relatively little effect on focal leakage as assessed by FA. This suggests that diffuse leakage may be a marker of VEGF-mediated leakage and that patients with predominantly diffuse pattern leakage may be more responsive to anti-VEGF therapy.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.