Tectonic lamellar keratoplasty (LKP) is often an emergent procedure performed in an effort to preserve globe integrity. Many of the ocular conditions which necessitate a lamellar graft are associated with abnormalities of wound healing and epithelial integrity. In these cases, a successful outcome is facilitated by obtaining a lamellar graft with intact epithelium and of uniform thickness matched to the lamellar bed. Less emergent indications for lamellar engraftment such as reconstruction of patients with limbal dermoid tumors or peripheral thinning of the cornea also benefit from a graft of uniform and predictable thickness which will match the lamellar bed without an override. Modern tissue harvesting techniques have prompted the development of several methods for harvesting lamellar grafts from readily available corneoscleral rims. A less time-consuming alternative utilizes a microkeratome to harvest the graft from rims affixed in an artificial anterior chamber (AAC). Using the microkeratome and an AAC to prepare lamellar graft tissue has advantages other than expediency. The graft thickness and diameter can be chosen to match the host site, and the resected surface is of “microkeratome quality” namely, more even surface, and more consistent graft thickness as compared to manual lamellar dissection techniques. The graft-host thickness match avoids wound discontinuities commonly encountered in hand dissected lamellar grafts. In certain situations, such as removal of a limbal dermoid by superficial keratectomy, the tapered edge created by the microkeratome blends seamlessly with the resection margin. The smooth graft-host junction promotes wound healing and comfort. A vertical edge can be obtained by harvesting an oversize lenticule of donor tissue, then trimming it to size with a trephine. This wound configuration may facilitate the creation of a water-tight closure in cases with perforation and descemetocele formation. Microkeratome harvested tissue usually retains the donor epithelium, avoiding the problems associated with postoperative epithelial defects. As the tissue is stored in Optisol, it is less edematous and easier to suture than tissue harvested from whole globes. In this chapter we will describe the set-up and use of the artificial chamber (Editorial Note: The term “artificial chamber” is used synonymously with “artificial anterior chamber”) to obtain lamellar graft tissue and present illustrative case studies with a more detailed description of the surgical treatment of limbal dermoid tumors.
