Post-operative 5-fluorouracil for glaucoma surgery.

BACKGROUND

Trabeculectomy is performed as a treatment for many types of glaucoma in an attempt to lower the intra-ocular pressure. The surgery involves creating a channel through the sclera, through which intra-ocular fluid can leave the eye. If scar tissue blocks the exit of the surgically created channel intra-ocular pressure rises and the operation fails. Antimetabolites are used to inhibit wound healing to prevent the conjunctiva scarring down on to the sclera. The principal antimetabolites used are 5-Fluorouracil and Mitomycin C. Both may be applied on a sponge between the conjunctiva and sclera at the beginning of surgery. 5-Fluorouracil may also be given as one or more injections under the conjunctiva after the surgery.

OBJECTIVES

The objective of this review is to assess the effects of post-operative injections of 5-Fluorouracil in eyes of people undergoing surgery for glaucoma.

SEARCH STRATEGY

We searched the Cochrane Eyes and Vision Group specialised register, The Cochrane Controlled Trials Register (CENTRAL), MEDLINE and EMBASE. We searched the reference lists of relevant articles for additional trials, and we used the Science Citation Index to search for articles that cited the included studies. We contacted investigators and experts for details of additional relevant trials.

SELECTION CRITERIA

We included randomised trials of post-operative 5-Fluorouracil injections compared to placebo injections or no injections in trabeculectomy for glaucoma.

DATA COLLECTION AND ANALYSIS

We independently assessed trial quality and extracted data. We contacted trial investigators for missing information. Data were summarised using relative risk, Peto odds ratio and weighted mean difference as appropriate.

MAIN RESULTS

Eight trials, which randomised a total of 536 participants, are included in the review. As far as can be determined from the trial reports, the methodological quality of the trials was not high. 5-Fluorouracil when delivered by post-operative injection appears to be effective in reducing the likelihood of surgical failure of trabeculectomy both in eyes at high risk of failure and those undergoing surgery for the first time. Complications are more common after 5-Fluorouracil injections, especially early and late wound leaks and temporary damage to the ocular surface. Whilst no evidence was found of an increased risk of serious sight threatening complications, people undergoing initial trabeculectomy had a substantially increased risk of ocular hypotony. None of the trials reported on the participants' perspective of care.

REVIEWER'S CONCLUSIONS: This treatment is now rarely used on the basis of a planned series of post-operative injections.This presumably reflects an aspect of the treatment that is unacceptable to both patients and doctors. None of the trials reported on the participants' perspective of care which constitutes a serious omission for an invasive treatment such as this. Increasingly, injections are used on an ad hoc basis. The effectiveness of this strategy is the subject of a future systematic review.