To report a case of late iatrogenic bleb formation and hypotony maculopathy after pterygium surgery applying Mitomycin C (MMC).

A 66‑year‑old man presented with an elevated, bleb‑like, fluid‑filled, cystic lesion on the nasal sclera of the right eye. The patient had undergone pterygium surgery with a combination of conjunctival autograft and adjuvant intraoperative MMC 0.02% four years before. The sclera seemed fistulized at the site of surgery and a thin layer of conjunctiva completely covered the lesion. A scleral patch graft was secured over the fistula with sutures, followed by excision of the thinned, avascular conjunctiva and advancement of the healthy adjacent conjunctiva to cover the patch graft.

One month later, a small bleb re?appeared adjacent to the scleral patch graft and IOP was 2 mmHg. Argon?laser treatment of the bleb was tried to induce scarring and reduction of bleb size, and was highly effective. After one week, IOP was increased to 8 mmHg. The clinical features remained stable four months after initial presentation.

Pterygium surgery using adjuvant MMC may result in late iatrogenic bleb formation and hypotony maculopathy. This complication can be successfully corrected surgically using a scleral patch graft combined with argon laser treatment over the inadvertent bleb.