Histopathology of deep anterior lamellar keratoplasty with pneumatic dissection: The "big-bubble" technique

PURPOSE: To describe characteristic histopathologic markers in deep anterior lamellar keratoplasty (DALK) using pneumatic dissection: Anwar "big-bubble" technique. METHODS: Case reports. Deep stromal buttons from 2 patients with keratoconus who had undergone DALK surgery using the "big-bubble" technique were examined by light microscopy. RESULTS: The histopathology of excised corneal buttons demonstrated multiple intrastromal spaces consistent with air bubbles. Apical stromal thinning seen clinically was not as readily appreciated on histopathology. CONCLUSIONS: Pneumatic dissection in DALK produces diffuse intrastromal air bubbles that may mask the corneal thinning that usually characterizes keratoconus histopathologically. This is a characteristic finding of which ocular pathologists and corneal surgeons should be aware.