New lamellar keratoplasty techniques: posterior keratoplasty and deep lamellar keratoplasty.

Posterior keratoplasty is a new surgical technique that may be valuable in treating patients with corneal decompensation secondary to endothelial dysfunction. There are currently two approaches to posterior keratoplasty. In the first approach, a corneal flap is created using a microkeratome (similar to laser in situ keratomileusis flap), and posterior stromal tissue is excised (by trephination or excimer laser keratectomy). In the second approach, a deep stromal pocket is created across the cornea through a superior scleral incision. A custom-made flat trephine is inserted into the pocket to excise a posterior lamellar disc. Preliminary studies have shown the feasibility of performing these techniques in sighted human eyes. Despite potential advantages, further clinical studies are needed to determine whether these techniques reduce interface scarring, astigmatism and graft rejection, improve visual outcomes, or are potentially an alternative for penetrating keratoplasty.