Background: Penetrating keratoplasty is one of the most common and successful ophthalmic procedures. However, controversy and uncertainty still call to question the significance of certain risk factors for graft failure.
Methods: A consecutive series of 1819 penetrating keratoplasties at a single center was studied to determine donor and recipient risk factors for graft failure. Mean follow up was 2.3 years (range, 1 to 96 months) with 139 (7.7%) eyes lost to follow up.
Results: Previous graft failure was the most significant risk factor for secondary failure (P = .0013). The risk of failure significantly decreased with increased postoperative time. Significant patient risk factors for secondary failures in initial grafts included race (P = .01), age (P = .004), iris color (P = .02), use of preoperative glaucoma medications (P = .0008), deep stromal vascularization (P = .002), and host horizontal diameter (P = 0.007). Significant risk factors for failures associated with immunologic allograft reactions in initial grafts included horizontal corneal diameter (P = .002), donor size (P = .05), differences between horizontal corneal diameter, and both donor size (P = .02) and recipient trephination size (P = .01). However, deep stromal vascularization was only marginally significant (P = .09). A history of preoperative glaucoma medication usage was not a significant risk factor.
Conclusions: The relationship of the recipient's horizontal corneal diameter to immunologic graft rejection is a new risk factor that surgeons can directly control and thereby help avoid graft failure.