Intravitreal dexamethasone implant in radiation-induced macular oedema.

Aims: To evaluate the efficacy and duration of activity of a single intravitreal dexamethasone implant in patients affected by radiation maculopathy.

Methods: Thirteen consecutive eyes of 13 patients affected by radiation maculopathy secondary to eye irradiation for a primary uveal melanoma (Iodine-125 brachytherapy) and treated with a single intravitreal 0.7 mg dexamethasone implant were retrospectively evaluated. Each patient underwent full ophthalmological examination, including fluorescein angiography and spectral domain optical coherence tomography (SD-OCT), even in en-face modality. Follow-up was performed monthly over a 6-month period.

Results: At preinjection visit, the median central subfield thickness (CST) by SD-OCT was 407 µm (IQR, 357-524 µm) and the median best-corrected visual acuity (BCVA) was 61 ETDRS score (IQR, 54-67). The median gain of ETDRS letter at 1 month was 6.5 (IQR, 4-15) (p<0.01). The median CST showed a reduction of 120 µm (IQR, 62-134) (p<0.01). Further CST reduction was reported at 2 months' follow-up, with CST stabilisation at 3 months and maintenance of BCVA. At 4, 5 and 6 months' follow-up, all patients presented progressive retinal thickening (p<0.01) and BCVA reduction (p<0.01). No side effects were documented.

Conclusion: Intravitreal dexamethasone implant reduces macular oedema secondary to radiation maculopathy and also improved visual acuity in a consistent proportion of patients. Signs of macular oedema recurrence may be detected at a median of 4 months after injection.