Fig. 4
From: Corneal surgery in keratoconus: which type, which technique, which outcomes?
DALK Big Bubble Technique. After a partial trephination of 70–80 % of the corneal stroma 30 G needle (a). Once the air is injected, it produces a dome-shaped detachment of the DM that is seen under the surgical microscope as a ring meaning that the big bubble has been formed (b). A lamellar dissection with a Crescent blade of the anterior stroma is then performed (c) followed by the removal of the stromal tissue above the DM plane with spatula and scissors (d), making sure to first exchange the air in the supradescemetic plane with viscoelastic to avoid puncturing DM inadvertently. When all of the stromal tissue is successfully removed, the DM exposed is characteristically smooth (e), and the donor cornea without its DM and endothelium is then sutured with the preferred suture technique (f)