A 69-year-old man was treated for a right ciliary body melanoma with plaque radiotherapy. One year later, he had uncomplicated cataract extraction but developed prolonged postoperative inflammation and secondary glaucoma. The tumour remained unchanged on yearly ultrasound B scans but intraocular pressures became uncontrolled despite maximal medical therapy. After radiotherapy, he underwent trabeculectomy with 5-fluorouracil and revision with mitomycin C 2 years later. The melanoma recurred with extrascleral extension under the trabeculectomy bleb 14 years after plaque radiotherapy and 5 years after trabeculectomy surgery. Enucleation was performed and histological analysis showed a ring melanoma involving the root of the iris, filling the trabecular meshwork and extending into the anterior chamber. The predominant cell type was epithelioid with large nuclei and prominent nucleoli. Trabeculectomy surgery may increase the risk of extrascleral extension of ciliary body melanoma even after apparently successful plaque radiotherapy and long-term local tumour control.