[Corneal epitheliopathy following trabeculectomy with postoperative adjunctive 5-fluorouracil]

The success of trabeculectomy in glaucoma not sufficiently controlled by maximal medical therapy substantially depends on postoperative scarring of the filtering bleb. This process of scarring can be inhibited by antimetabolites like mitomycin C (MMC) and 5-fluorouracil (5-FU). The aim of this study is the evaluation of incidence and long-term outcome of corneal surface defects and intraocular pressure following MMC- or 5FU-trabeculectomy using different doses of postoperative 5FU.

A retrospective, non-randomised comparative study of 381 patients undergoing trabeculectomy with intraoperative application of either 5FU (group A, n = 169) or MMC (group B, n = 212) was performed. Based on the Wuerzburg bleb classification score (WBCS) for postoperative wound healing evaluation, 30 of these operations of group A (group B: n = 26) did not receive 5 FU postoperatively (controls), 67 (93) received up to 7 postoperative injections of 5 mg 5 FU (normal dosage group), and 72 (93) received more than 7 injections (high dosage group). Surface epithelial defects were routinely assessed by slit-lamp microscopy and fluorescein staining. Intraocular pressure (IOP) was measured by Goldmann applanation tonometry.

In the normal dosage group the mean total dose of 5 FU was 25.8 ± 9.1 mg in group A (group B: 28.4 ± 7.5 mg) and in the high dosage group 54.2 ± 10.9 mg 5 FU (51.7 ± 11.8 mg), respectively. Increased doses of postoperative 5 FU induced more frequent corneal erosions in both groups. Corneal erosions were seen in controls in 16.7 % (26.9 %), in the normal dosage group in 55.2 % (47.3 %) and in the high dosage group in 77.8 % (59.1 %) in group A and group B, respectively. The incidence of a corneal erosion between group A and group B did not differ significantly (p = 0.074). The mean reduction of intraocular pressure in mmHg did not show a significant difference 12 months after trabeculectomy between controls and postoperative 5-FU operations.

In eyes with beginning scarring of the filtering bleb after trabeculectomy the subconjunctival injection of 5-FU allows a similar reduction of intraocular pressure as in eyes without scarring. Corneal epitheliopathy following trabeculectomy and postoperative 5 FU is dose-dependent with higher doses leading to a higher incidence of corneal erosions. As serious corneal long-term complications are rare, risk-benefit analysis justifies the application of 5-FU after filtrating glaucoma surgery.