Management of hypotony after glaucoma filtering surgery

A 39-year-old male with open angle glaucoma in both eyes visited our clinic. The intraocular pressure (IOP) of both eyes fluctuated between 15 mmHg and 25 mmHg. The best corrected visual acuity (BCVA) was 20/20 in the right eye and 20/100 in the left eye. He underwent trabeculectomy with an adjunctive agent (mitomycin C; concentration, 0.2 mg/mL) smoothly on the right eye. After the removal of releasable sutures, the filtering bleb was prominent over the superior limbus for 3 consecutive clock hours with an IOP of about 4-5 mmHg. The Seidel test result was negative, and the anterior chamber depth was moderate to deep. The BCVA of the right eye decreased to 20/100, and optical coherence tomography revealed macular edema. We injected sodium hyaluronate (Healon, Abbott Medical Optics, Santa Ana, CA, USA) into the anterior chamber 2 months after the operation, and repeated the same procedure 4 days later. After each injection, the IOP spiked up to 50 mmHg, and an intravenous infusion of mannitol was required. Sodium hyaluronate was found migrating into the bleb on post-injection day 1. Then we decided to revise the bleb by suturing the scleral flap at two sides. The IOP of the right eye returned to 10 mmHg 4 days after the revision surgery. The BCVA of the right eye recovered to 20/20 6 months after the revision. Optical coherence tomography also showed recovery from macular edema. One IOP-lowering agent (1% brinzolamide ophthalmic suspension) was required for IOP control after bleb revision. Early revision of the scleral flap may resolve hypotony and associated serious complications.