Younger age, high IOP risk factors for glaucoma surgery failure

ROCKVILLE, MD — Younger patients, with elevated levels of intraocular pressure before intervention, were more likely to have surgical treatments for glaucoma fail, according to a large, randomized, multicenter study.

The study is part of the results of the Advanced Glaucoma Intervention Study (AGIS), sponsored by the National Eye Institute and the Office of Research on Minority Health. This portion of the study analyzed 789 eyes randomly treated with two surgical sequences: one began with trabeculectomy, the other with argon laser trabeculoplasty (ALT). Patients enrolled had not had previous trabeculectomy or incision surgery, and their glaucoma could no longer be treated via medication.

Younger age and an elevated pre-intervention IOP were associated with an increased failure rate of either treatment sequence. For those who received trabeculectomy first, diabetes mellitus was also a predisposing factor. Postoperative complications, such as marked inflammation, were indicative of a failure with a second trabeculectomy.

Patients were randomized to surgery sequences. In one, patients first received ALT, followed by trabeculectomy. If that failed, they received a second trabeculectomy. A second group received trabeculectomy first, followed by ALT and then another trabeculectomy. The risk factors were associated with failure with first or second treatments. Not all of the eyes went on to receive the second or third surgical treatments in the sequence.

Several factors were irrelevant to the risk of failure, such as race and AGIS glaucoma intervention. Prior trabeculectomy failure did not affect the failure rate of ALT, and the reverse was also true. Time did not appear to affect the failure rate of a third trabeculectomy.

Other factors could benefit the prognosis, such as the use of antifibrotic agents and new glaucoma medications. The older a patient was before intervention, the more the risk for failure of ALT and trabeculectomy decreased.

Similar studies have not found an association between age and surgical failure. Researchers said this study is significant because of the large population studied and long follow-up period. The study is published in the October issue of the American Journal of Ophthalmology.