Choroidal Volume is Affected During Treatment for Neovascular AMD

Abstract

Purpose : Current treatment for neovascular AMD, NVAMD, involves inhibition of vascular endothelial growth factor (VEGF), but little research exists concerning the extent of choroidal changes following therapy. Many groups have reported progressive RPE atrophy during anti-VEGF treatment for neovascular AMD, and reduction of central choroidal thickness has been associated with progressive RPE atrophy. Our group and others have linked this reduction of central choroidal thickness to progressive atrophy associated with anti-angiogenic therapy for NVAMD. Therefore, in order to better delineate the affects of pathological neovascularization and the associated treatment with anti-VEGF compounds, we sought to proceed with a retrospective clinical study to evaluate changes in choroidal volumes in this cohort of patients.

Methods : Anti-VEGF treatments were controlled for by selecting patients exclusively undergoing anti-VEGF therapies for neovascular AMD. Optical Computed Tomography (OCT) was utilized in conjunction with Heidleberg Eye software to attain average choroidal volumes from (n=24) patient eyes. Volumes were attained by drawing parallel lines across OCT imagery outlining both choroid-sclera junctions and Bruch's membrane for 40 images per left and right eye. Average posterior choroidal thickness and volumes (mm³) were calculated by the software for 2 sets of measurements per eye. Each set selected was seperated by 6 month time spans between patient treatments. Measurements were performed by a masked observer.

Results : Volume averages showed a 9/n=24, or 37.5% preference towards decreased choroidal volumes with a range of (-)1.09 mm³- (-)0.27 mm³. Finally, 5/n=24, or 20.1% patients identified preference towards minimal change in volumes over the same inteval with a range of (-)0.01- (+)0.09. Both neovscularization and anti-VEGF treatment diminished choroidal volume.

Conclusions : Central choroidal thickness is diminished both at the onset of neovascular AMD, and further decreases during anti-VEGF treatment compared to the fellow untreated eye. Choroidal volume is also significantly lowered . Thus, the altered mileu of pro-angiogenic cytokines associated with the onset of choroidal neovascularization attenuates choroidal thickness and volume. This observed loss of choroidal thickness and volume is worsened after anti-VEGF therapy.

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