Long-term outcome of trabeculectomy in terms of intraocular pressure.

PURPOSE: To evaluate the outcome, long-term results and contributing prognostic factors of trabeculectomy in terms of intraocular pressure (IOP) and to compare the results in primary open-angle glaucoma (POAG) and exfoliation glaucoma (EG).

METHODS

This study involved retrospective evaluation of 138 consecutive patients (138 eyes) with either POAG or EG. All patients had undergone primary trabeculectomy performed by the same surgeon between November 1994 and August 1996. Only one eye per patient was included. Operations performed with the use of antimetabolites were excluded. All patients were aged over 40 years and were white. Follow-up for all subjects lasted at least 2 years. Successful control of IOP was defined as achieving IOP < or = 21 mmHg without medication (complete success) or with a single topical medication (qualified success). Success rates were determined using the Kaplan-Meier survival curve, and risk factors were analysed with proportional hazards regression.

RESULTS

According to the Kaplan-Meier survival curve, success rates (complete or qualified) were 82% at 1 year, 70% at 2 years, 64% at 3 years and 52% at 4 years. A total of 63% were complete successes 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 EG group. Proportional hazards regression analysis showed that the presence of EG and early postoperative IOP > 30 mmHg decreased the possibility of complete success, while a cataract operation performed during follow-up improved it.

CONCLUSION

The IOP-reducing effect of trabeculectomy decreases gradually. After 4 years, 52% of operated eyes had IOP < or = 21 mmHg with or without a single topical medication. Diagnosis of EG implied a worse long-term outcome for trabeculectomy in terms of IOP.