Which of the following is considered the most common cause of late corneal graft failure after penetrating keratoplasty?

Explanation

Endothelial graft rejection is the most common cause of late corneal graft failure after penetrating keratoplasty (PKP). It typically presents with signs such as corneal edema, anterior chamber inflammation, keratic precipitates on the graft endothelium, and a Khodadoust line (a line of inflammatory cells on the endothelium). While graft infection, primary graft failure (failure of the graft to clear immediately post-op), and post-operative glaucoma are significant complications, endothelial rejection accounts for the majority of late failures.