Prospective evaluation of CO2 laser-assisted sclerectomy surgery (CLASS) with Mitomycin C

Purpose: Our purpose was to evaluate the clinical safety and efficacy of CO2 laser-assisted sclerectomy surgery (CLASS) with Mitomycin C (MMC) in open angle glaucoma (OAG).Methods: This was a prospective, uncontrolled, interventional case series. All subjects underwent CLASS procedure by a single surgeon. After the dissection of a partial thickness scleral flap, topical MMC 0.2 mg/ml was applied to the sclera and the conjunctiva for 3 min. The CO2 laser with a beam-manipulating system was used to ablate the scleral tissue and expose the Schlemm’s canal area. Primary outcomes: intraocular pressure (IOP) change, number of IOP-lowering medicaments change. Adverse events were evaluated as secondary outcomes. Results: Twenty-one eyes of 21 patients underwent the CLASS procedure. Thirteen were primary OAG (62%), two normal pressure glaucoma (10%), three exfoliative glaucoma (14%) and three others secondary OAG. With a mean (SD) follow-up of 15.3 (5.9) months, the IOP changed from 25.4 (6.7) mmHg at baseline to 10.9 (3.4) mmHg al the last visit. Mean reduction of IOP was −14.5 mmHg (95% CI, −17.7 to −11.2, P < 0.001). The median (IQR) number of IOP-lowering medication decreased from 3 (3–3) at baseline to 1 (0–1) at the last visit (P < 0.001). Visual acuity did not change significantly. Adverse events: five eyes (24%) developed iris adhesion to the filtration area that was successfully managed with office-based procedures. In one case (5%), CLASS was converted to trabeculectomy due to intraoperative perforation of the ablated area. There was one case of hypotony maculopathy successfully treated with placement of additional transconjunctival scleral flap sutures. Conclusions: The CLASS procedure with MMC is clinically safe and effective maintaining a large reduction in IOP and in the number of IOP-lowering medications with a mean follow-up of 15 months. Iris adhesion at the filtrating area warrants further evaluation and possibly reflects the surgeon’s learning curve.