Optical coherence tomography angiography analysis of retinal and choroidal flow after proton beam therapy for uveal melanoma

Abstract

Purpose : To evaluate the retinal and choroidal circulation in the macular and peripapillary area in eyes with unilateral choroidal melanoma treated with proton beam therapy using optical coherence tomography angiography (OCTA)

Methods : This was a prospective, cross-sectional study of twenty-three patients with unilateral choroidal melanoma treated with proton beam radiation at least one year earlier and with normal contralateral eye who agreed to participate in the study. Clinical parameters including visual acuity (VA) and tumor size or location were recorded. Optovue AngioVue® was utilized to obtain standard OCT and OCTA images of the macula (6.0mm) and peripapillary region (4.5mm around optic disc) of both eyes. The contralateral eye served as control. Only OCTA images with signal strength of > 5 with included in the analysis. Student’s t-test or Wilcoxon signed rank test was used to analyze for continuous variable differences between the tumor eye and contralateral eye.

Results : Based on image quality, twenty-one patients were included in the study analysis. The median patient age was 72 years (range, 20-87 years). On OCTA, a significant decrease in peripapillary capillary flow density and optic disc RNFL thickness in the tumor eyes was observed compared with the fellow eye (p< 0.01). In the macula, the tumor eyes had significant increase in fovea avascular zone area and decrease in vascular density of the superficial capillary plexus (P- values <0.01, respectively). The deep capillary plexus was not significantly affected. There was a decrease in choroidal flow in the macula of borderline significance in the tumor eye (P-value 0.04).

Conclusions : Based on OCTA, proton beam radiation decreased the flow of peripapillary capillaries and macular superficial capillary plexus in eyes with choroidal melanoma. Macular deep capillary plexus flow and choroidal flow appear relatively less affected by proton beam radiation in our study population.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.