Does titration of mitomycin C as an adjunct to trabeculectomy significantly influence the intraocular pressure outcome?

Susan J Lee¹, Augusto Paranhos², M Bruce Shields¹

¹Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut, USA; ²Federal University of São Paulo, São Paulo, Brazil

Purpose: To evaluate the benefit of titrating the concentration and exposure time of mitomycin C (MMC) as an adjunct to trabeculectomy.

Methods: This report consists of a retrospective study and a review of the literature. In the study, consecutive glaucoma patients were evaluated who underwent trabeculectomy with adjunctive MMC that was titrated for concentration and exposure time, based on patient’s risk factors for surgical failure. After minimum follow-up of 6 months, patients were divided into success (intraocular pressure 7–17 mmHg), hypertension (>17 mmHg) and hypotony (<7 mmHg) groups, which were compared with regard to MMC protocol and patient variables. The literature review included reports of trabeculectomy and adjunctive MMC with and without titration.

Results: One hundred and fifty-five eyes of 155 patients were studied. There were no significant differences between the three outcome groups and MMC protocol (p > 0.05). The only significant patient variable was older age in the hypotony group (p = 0.009). The literature is conflicting regarding the value of titrating MMC as an adjunct in trabeculectomy.

Conclusion: The outcome of trabeculectomy with adjunctive MMC appears to represent a complex interaction of patient and surgical variables. While there is some support for a benefit of titrating MMC according to individual patient variables, there is inadequate evidence at the present time to claim superiority for any MMC protocol, with or without titration.

Keywords: glaucoma surgery, trabeculectomy, mitomycin C, intraocular pressure