Scott et al. (1602) report the results of a retrospective study evaluating the effect of topical ketorolac 0.5% following Ahmed implantation. The medical records of consecutive patients who underwent placement of an Ahmed glaucoma valve (models S2 or FP7) at the University of Michigan were reviewed. Preoperative and postoperative data were compared between 14 eyes that received ketorolac postoperatively and 50 eyes that did not receive a topical NSAID. All patients in the study were also treated with topical prednisolone acetate 1%, and the frequency of topical corticosteroid administration was not significantly different between the two groups at three months and thereafter. Mean preoperative IOP was similar between the ketorolac and no ketorolac groups (35.1 ± 11.9 mmHg vs 37.0 ± 12.2 mmHg, p = 0.60). The use of ketorolac following Ahmed implantation was associated with lower mean postoperative IOPs from six to eight weeks to 12 months, although the differences in IOP levels was only statistically significant at 6 months (13.1 ± 3.7 mmHg vs 19.5 ± 9.3 mmHg, p = 0.0003). The mean number of glaucoma medications was similar between the two groups. Previous studies have reported a higher incidence of bleb encapsulation (or hypertensive phase) with the Ahmed glaucoma valve compared with non-valved implants.
The interesting question is raised of whether postoperative topical ketorolac improves the function of Ahmed implants
Immediate filtration of aqueous humor rich in inflammatory mediators may stimulate the creation of a thicker capsule around the end plate following valved implant placement. The authors hypothesize that the anti-inflammatory properties of ketorolac may reduce fibrosis around the plate and produce lower IOPs. The study limitations have been appropriately acknowledged by the authors, including the retrospective design, small number of patients in the ketorolac group, and limited follow-up. It is also noteworthy that the group that did not receive ketorolac had more patients with neovascular glaucoma (34% vs 21%), black race (10% vs 0%), and S2 implants (18% vs 0%), and these are all factors that have been reported to increase the risk of surgical failure with the Ahmed glaucoma valve. Despite these limitations, the study raises the interesting question of whether postoperative topical ketorolac improves the function of Ahmed implants. Future randomized prospective studies could provide additional information to more definitively answer this question.