Endoscopic visualisation to aid deep anterior lamellar keratoplasty

The aim of this study was to assess the value of endoscopy during deep anterior lamellar keratoplasty (DALK) by visualising the posterior cornea. This allows the surgeon to determine whether air injection had succeeded in stripping Descemet's membrane and endothelium from the posterior corneal stroma.

Four whole globes for research were obtained from the Florida eye bank with consent. A 2 mm incision was placed at the limbus and the endoscope was introduced through this into the anterior chamber. A 26-gauge needle was introduced into the cornea with the bevel positioned as deep as possible and air injected into the corneal stroma. Air was injected until the whole cornea became opaque and repeated air injections were made even after an opaque cornea was noted. The endoscopic camera was used to visualise the posterior corneal surface during this procedure.

The view of the posterior corneal surface was clear and introduction of the probe did not interfere with the air dissection. In all four eyes, despite ease of air injection and diffuse corneal air infiltration, no large air bubble dissection of Descemet's membrane from adjacent stroma occurred. Instead multiple blistering of the posterior corneal surface could be seen.

Endoscopy provides an effective tool to visualise the posterior corneal surface during DALK, using air dissection. This technique may become a standard adjunctive procedure during DALK.