A Case of Long-Term Undiagnosed Cyclodialysis Cleft Following Tanito Microhook Trabeculotomy

Persistent hypotony following Tanito microhook trabeculotomy (TMH) is rare but may occur due to the development of cyclodialysis clefts. We report a case of a Japanese man in his 40s who developed persistent hypotony and hypotony maculopathy after TMH in the left eye. Fourteen months after the surgery, the patient was referred to our institution due to prolonged hypotony that remained undiagnosed and untreated despite evaluations with gonioscopy and anterior segment optical coherence tomography (AS-OCT) at the referring clinic. At our institution, default AS-OCT scans and gonioscopy also failed to identify the cleft due to anterior iris rotation caused by ciliary body detachment. However, manual AS-OCT scans successfully revealed angle detachment and irido-trabecular contact at 203°. The patient underwent combined cataract surgery and direct internal cyclopexy to repair the cyclodialysis cleft. While the surgery successfully resolved hypotony, it resulted in elevated intraocular pressure, necessitating Ahmed glaucoma valve implantation. This case emphasizes the importance of detailed AS-OCT scanning in detecting subtle cyclodialysis clefts and highlights direct internal cyclopexy as an effective treatment option for prolonged hypotony after TMH.