We avoided making the section through the trephine bleb because of possible interference with its function, and because in several cases prior to this series unfortunate end results had followed section through the bleb. We did not make the section in the clear cornea anterior to the bleb because of the difficulty of removing a lens in its capsule from under an overhanging shelf and the fear of corneal scarring in the pupillary area.
Reference: Callahan A. Cataract extraction after glaucoma surgery: lateroinferior approach following filtering glaucoma operation. Arch Ophthalmol. 1952;47:133.
A look at the past . . .. Arch Ophthalmol. 2008;126(3):403. doi:10.1001/archopht.126.3.403