The trabeculectomy procedure was modified with the introduction of the Kelly Descemet membrane punch. Using this punch, a few limbal tissue sections (0.25 ×0.30 mm) were easily excised from beneath the scleral flap base. Mitomycin C (MMC) was used. Among the 100 most recent operations in which this punch was used, no patients developed severe shallow anterior chambers over ten days. Because MMC is so effective and active for a long period, small excision surgery using this punch should be reconsidered.