Quantitative OCT Angiography Evaluation of Peripapillary Retinal Circulation after Plaque Brachytherapy

Purpose To study peripapillary retinal capillary circulation in eyes treated with iodine 125 (I 125 ) plaque brachytherapy for uveal melanoma using optical coherence tomography angiography (OCTA). Design Cross-sectional study of 10 participants imaged with OCTA before uveal melanoma treatment and 15 participants imaged after development of radiation retinopathy, optic neuropathy, or both. Participants After institutional review board approval, participants were enrolled from an academic ocular oncology clinical practice. All participants had uveal melanoma in 1 eye, and treatment with I 125 plaque brachytherapy was planned or had taken place previously. Patients with low vision at baseline and uncontrolled hypertension were excluded. In the posttreatment group, 7 participants were men and 8 were women; age range was 38 to 81 years. Visual acuities in the irradiated eyes ranged from 20/20 to counting fingers. Visual acuities in the untreated fellow eyes were 20/25 or better. Methods Peripapillary retinal capillary circulation was measured by OCTA (Optovue, Inc). Optic disc scans measuring 4.5 × 4.5 mm were obtained. Main Outcome Measures The relationship of the peripapillary retinal capillary density (PPCD) as measured by OCTA to the calculated dose to the optic nerve (the dose to 50% of the disc [D50]) and visual acuity in logarithm of the minimal angle of resolution units were evaluated. Results No significant differences were observed in the PPCD as measured by OCTA when comparing the eye with melanoma with the fellow eye before brachytherapy; however, the PPCD was significantly lower in treated eyes (52.9% ± 22.4%) than in fellow eyes that did not receive radiation (73.3% ± 13.7%; P  = 0.004). There was an inverse linear correlation between D50 and the PPCD (Pearson's r  = −0.528; P  = 0.043) and between visual acuity and the PPCD (Pearson's r  = −0.564; P  = 0.028). Conclusions Among patients with clinically apparent radiation retinopathy, radiation optic neuropathy, or both, PPCD was lower in the treated eye and correlated with the radiation dose to the optic nerve and the visual acuity. Optical coherence tomography angiography provides a measure of capillary changes after radiation and may serve as a quantitative end point to address visual prognosis.