**8.1.6 Persistent epithelial defect**

Careful handling of the donor cornea intraoperatively is imperative to avoid damaging the epithelium. Good wound apposition and prevention of an overriding edge leads to better tear-film distribution and a reduced incidence of epithelial defects. A persistent epithelial defect has the potential to secondary infection thus reepithelialization and the maintenance of an intact epithelium is critical for postoperative wound healing, graft survival, and protection against infection and melting. Initial treatment requires application of topical lubricants and if it persists a permanent or temporary tarsorrhaphy early in the postoperative period can be performed. Alternatively, botulinum A toxin injected into the elevator muscle to induce a complete ptosis, may help reduce the severity and persistence of an epithelial defect.

The use of preservative-free medication is recommended to reduce the risk of epithelial toxicity and corticosteroids may need to be decreased.
