Effect of different application depths of mitomycin-C in deep sclerectomy with collagen implant: a randomized controlled trial

To evaluate effects of mitomycin-C (MMC) in deep sclerectomy with collagen implant applied under the superficial scleral flap or under the deep scleral flap. Twenty-five patients with primary or secondary open-angle glaucoma and at high risk for postoperative cicatrization underwent deep sclerectomy and were randomly distributed to the two treatment arms. In the superficial MMC group (S-MMC), MMC was applied under the superficial scleral flap using a soaked sponge for 60 s; in the deep MMC group (D-MMC), MMC was applied under the deep scleral flap for 60 s before entering the Schlemm's canal. In both groups, remaining MMC was irrigated with 40 mL balanced salt solution. Patients were followed up for up to 2 years. The volume of filtering blebs was studied with ultrasound biomicroscopy at the last follow-up visit. Mean preoperative intraocular pressure (IOP) was 20.5 +/- 8.9 mmHg for D-MMC and 21.6 +/- 6.6 mmHg for S-MMC eyes (P = 0.67). The mean postoperative IOP was 5.3 +/- 3.3 mmHg (D-MMC) and 6.9 +/- 4.8 mmHg (S-MMC) at day 1 (P = 0.22) and 11.4 +/- 6.3 mmHg (D-MMC) versus 11.3 +/- 4.6 mmHg (S-MMC) at last follow up (P = 0.54). The mean number of medications per patient was reduced from 2.5 +/- 0.5 to 0.4 +/- 0.5 (D-MMC) (P < 0.001) and from 2.5 +/- 0.9 to 0.3 +/- 0.4 (S-MMC) (P < 0.001). Ultrasound biomicroscopy at 24 months showed mean intrascleral space volume of 1.97 +/- 0.35 mm3 (D-MMC) and 5.68 +/- 0.42 mm3 (S-MMC) (P < 0.05). No significant difference in efficacy and safety was found between the two groups at a mean of 19.2 months of follow up. Deep scleral application of MMC, however, seems to produce significantly smaller intrascleral blebs.