To compare the bleb morphology and surgical outcomes of a limbus-based group with those of a fornix-based group who underwent trabeculectomy with mitomycin C (MMC).

Sixty-five eyes of 59 patients who had undergone trabeculectomy with MMC and who were observed for one year or more were included in the present study. A limbus-based conjunctival flap was used for 34 eyes of 31 patients and a fornix-based conjunctival flap for the other 31 eyes of 28 patients. The bleb morphologies were classified and compared after one year or more postoperatively according to the Moorfield Bleb Grading System, and intraocular pressure and success rates were evaluated.

The central bleb vascularity of the limbus-based group was statistically significantly lower than that of the fornix- based group (1.79 ± 0.64; 2.16 ± 0.73, p = 0.042). The risk of cystic bleb formation was higher in the limbus-based group (38.2%; 16.5%, p = 0.047). There were no differences in the IOP or success rate between the two groups.

There were no differences between the two groups with regard to the IOP or cumulative success rate. However, in the fornix-based group, the central bleb vascularity was lower and the risk of avascular cystic bleb formation was higher than those in the limbus-based group.