Corneal transillumination: technique to detect big bubble in deep anterior lamellar keratoplasty.

Deep anterior lamellar keratoplasty is a widely adopted technique to treat pathologies of the cornea without endothelial cell involvement. This technique has several advantages including longer graft survival without endothelial rejection and lower doses of steroid administration. A transillumination technique was used to diagnose big bubble formation. A partial-thickness trephination was made, followed by superficial keratectomy and air injection into the stroma. Then, a vitreoretinal endoilluminator was used to illuminate the cornea and check for any signs of "full moon" or "waning moon," which corresponded to the shine of the big bubble from total internal reflection of light. Once the diagnosis was made, the remnant stroma was removed, and the donor cornea without endothelium was sutured. An advantage of this technique was that it allowed the diagnosis of big bubble even on an opaque or whitish emphysematous cornea when other methods could not be used.