OCT Angiography Analysis of Retinal and Choroidal Flow after Proton Beam Therapy for Choroidal Melanoma

Abstract

Purpose

To evaluate the macular and peripapillary retinal and choroidal flow changes in eyes with choroidal melanoma (CM) treated with proton beam radiation therapy (PBRT) using OCT angiography (OCTA).

Design

A prospective, cross-sectional, single-center study.

Participants

All patients seen at the study center between 2019 and 2024 who received PBRT for CM in 1 eye ≥1 year before enrollment with best-corrected visual acuity (BCVA) >20/200, unremarkable contralateral eye, and agreed to participate.

Methods

After a comprehensive eye examination, including BCVA, Optovue AngioVue was used to obtain the 4.5-mm optic disc and 6.0-mm macular OCT/OCT angiography (OCTA) images of both eyes. All vascular density (VD) measurements were obtained automatically using the OCTA software, except choriocapillaris VD, which was quantitated using ImageJ. The Wilcoxon signed-rank test was used to analyze differences in OCT/OCTA parameters between the treated and the contralateral eyes. Spearman’s ρ was used to identify OCTA parameters associated with BCVA or radiation dose. A P value of <0.05 was considered statistically significant.

Main Outcome Measures

Foveal avascular zone (FAZ) area and perimeter, choriocapillaris and retinal (superficial and deep) capillary VD in the macula and radial peripapillary capillary (RPC) VD on OCTA; macular and retinal nerve fiber layer thickness on OCT, tumor location, laterality and size at baseline, BCVA of both eyes, PBRT dose, and duration of follow-up at enrollment.

Results

Among 24 participants, OCT/OCTA parameters were significantly different in the treated eyes when compared with the contralateral eyes, including increased FAZ area and perimeter, decreased peripapillary retinal nerve fiber layer thickness and RPC VD, and decreased macular choriocapillaris VD and parafoveal and perifoveal superficial retinal plexus VD (P < 0.05). Best-corrected visual acuity in the treated eyes correlated significantly with FAZ area and perimeter, parafoveal and perifoveal deep retinal plexus VD, and radiation dose to fovea but not radiation dose to the optic disc.

Conclusions

Although PBRT can affect both retinal and choroidal vascular flow in the macular and peripapillary region in eyes with CM, BCVA after PBRT seems to correlate best with the retinal vascular flow changes in the macula on OCTA and radiation dose to the fovea.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.