IOP-reducing effect of trabeculectomy decreases over time

HELSINKI, Finland — The intraocular-pressure-reducing effect of trabeculectomy decreases gradually, according to a long-term study. Patients with exfoliation glaucoma in the study were more likely to have a worse long-term outcome than patients with primary open-angle glaucoma, the study authors said.

Researchers here evaluated 138 consecutive patients with either POAG or exfoliation glaucoma. All patients had undergone primary trabeculectomy between 1994 and 1996. Only one eye per patient was included in the study. Operations performed using an adjunctive antimetabolite were excluded from analysis. All patients were white and all were older than 40. Follow-up was at least 2 years.

Success was defined as an IOP of 21 mm Hg or less without medication (complete success) or with one topical medication (qualified success).

Overall success rates were 82% at 1 year, 70% at 2 years, 64% at 3 years and 54% at 4 years. Complete success rates were 63% at 1 year, 54% at 2 years, 45% at 3 years and 40% at 4 years.

Complete success rates were significantly better in the POAG group than in the exfoliation glaucoma group. The presence of exfoliation glaucoma and early postoperative IOP of greater than 30 mm Hg decreased the possibility of complete success, while cataract removal during follow-up improved the likelihood of complete success.

The study is published in the June issue of Acta Ophthalmologica Scandinavica.