Long-term follow-up of anatomical and functional macular changes after a single intravitreal implant of dexamethasone 0.7 mg for radiation macular edema secondary to proton beam therapy for choroidal melanoma

Purpose: To describe the efficacy and safety of a single intravitreal implant of dexamethasone in a patient affected by radiation maculopathy due to proton beam radiotherapy for choroidal melanoma. Patient and methods: Retrospective data of a 46-year-old woman treated with a single intravitreal injection of dexamethasone for radiation maculopathy due to proton beam radiotherapy were collected. The main outcome measures were best-corrected visual acuity and central retinal thickness. Intraocular pressure, anterior segment evaluation with slit lamp, macular changes depicted with spectral domain optical coherence tomography, retinal perfusion studied with fundus fluorescein angiography, and grade of macular edema using the Horgan classification were also evaluated during a 16-month follow-up. Results: Macular edema occurred 25 months after radiation treatment in the left eye. The patient underwent a single intravitreal implant of dexamethasone. Preinjection visual acuity and central retinal thickness were 6/12 and 502 μm, respectively. After 8 months, visual acuity was 6/6 and remained stable until 16 months. Central retinal thickness was 269 μm at 16 months. Conclusion: A single intravitreal implant of dexamethasone could effectively and stably improve visual acuity and central retinal thickness in some patients with radiation macular edema for 16 months after injection.