Combined penetrating keratoplasty and limbal allograft transplantation for severe corneal burns.

The management of ocular surface disease presents a significant challenge to ophthalmologists. Recent advances in the etiology and pathophysiology of ocular surface diseases, such as chemical and thermal burns or Stevens-Johnson syndrome, include the concept of the limbal stem cell. Limbal stem cell theory suggests that the corneal limbus contains epithelial stem cells that are responsible for a continuous supply of corneal epithelial cells, which not only migrate from the deep to superficial epithelial layers, but also progress in a centripetal direction, inward from the limbus. Support for this concept is provided indirectly by the relatively poor prognosis for penetrating keratoplasty for these types of ocular surface diseases. In such cases, it is suggested that limbal damage and depletion is present and is a significant factor in loss of integrity of the ocular surface; therefore, conventional penetrating keratoplasty, which does not include limbal tissue, does not have a high success rate.