AAO 2020 Video Program
    Cornea/External Disease

    Keratoconus cases that showed progression on follow-up that were not eligible for collagen crosslinking and were too early to be candidates for deep anterior lamellar keratoplasty/penetrating keratoplasty were enrolled for the procedure after informed consent was obtained. After the donor cornea was mounted on a Barron artificial anterior chamber, first the epithelium was debrided and the stroma was delineated from the Bowman membrane by injecting air. The Bowman layer was then identified by staining with trypan blue. A 360 scoring was done with a bent 26-gauge needle to delineate the Bowman membrane. Using a crescent blade and fine toothed forceps, the Bowman membrane was gently separated from the underlying stroma. Corneoscleral tunnel was done superiorly / temporally, and the same tunnel was extended throughout the cornea from limbus to limbus at midstromal level with the help of regular crescent blades and lamellar dissectors. The harvested Bowman layer was then inserted into the stromal pocket with the help of a lens glide, and any folds in the layer were ironed out with a spatula. In our study all the three cases showed considerable visual improvement and stabilization of astigmatism in the early postoperative period.