Viscocanalostomy for primary open-angle glaucoma: the Gross Pankow experience

To assess the pressure-lowering effect and postoperative complications of the viscocanalostomy nonpenetrating filtering procedure. A private practice ophthalmic surgery referral center. Fifty-six eyes of 41 patients with medically uncontrolled primary open-angle glaucoma had a viscocanalostomy. After a superficial scleral flap was raised, a deep sclerectomy was performed in the scleral bed with deroofing of Schlemm’s canal and preparation of a window of Descemet’s membrane. The ostia of Schlemm’s canal were probed and stretched with sodium hyaluronate 1.4% (Healon GV®), and the scleral flap and conjunctiva were sutured. Examinations were performed before surgery and 1, 3, and 14 days and 1, 3, 6, and 12 months postoperatively. Mean preoperative intraocular pressure (IOP) was 28.1 mm Hg ± 7.4 (SD) with a mean of 2.4 ± 0.7 medications. Mean postoperative IOP was 18.6 ± 7.5 mm Hg with 0 medications at 1 day, 17.4 ± 5.2 mm Hg with 0.1 medications at 3 days, 19.1 ± 4.3 mm Hg with 0.1 medications at 14 days, 19.4 ± 4.3 mm Hg with 0.4 medications at 1 month, 18.3 ± 3.6 mm Hg with 0.6 medications at 3 months, 18.0 ± 2.6 mm Hg with 0.6 medications at 6 months, and 17.8 ± 3.8 mm Hg with 0.7 medications at 1 year. After 1 year, IOP was lower than 21 mm Hg without medication in 36% of patients and lower than 21 mm Hg with medication in 79%. Five patients (9%) required a second operation for pressure control. The following postoperative complications occurred: hyphema (2%); postoperative hypotony less than 10 mm Hg (2%); positive Seidel test (17%); further surgery to lower IOP (12%). Cataract surgery was performed in 1 patient (2%) at 4 months. Despite an attempt to close the scleral flap watertight, 26 patients had evidence of subconjunctival drainage (conjunctival microcysts or filtration bleb) at 1 year. Viscocanalostomy lowered IOP and reduced the need for pressure-controlling medications with a low postoperative complication rate. The high success rates of earlier publications were not reproduced.