Abstract
Purpose: :
To study the histopathological features of graft failure following endothelial keratoplasty (EK).
Methods: :
All cases of EK failure over a 24 month period in one unit were included. Transplantation indication, surgical history, donor age and endothelial count were obtained by retrospective case-note review. Corneal button specimens from repeat EK/penetrating keratoplasty (PK) were examined by histopathological methods.
Results: :
8 patients were included; age 51-83 (mean 70.6) years. Indications for EK were Fuchs’ endothelial dystrophy (n=4), pseudophakic bullous keratopathy (n=3) and traumatic endothelial damage secondary to glaucoma drainage valve (n=1). Donor age was 61-92 (mean 74.9) years, with endothelial counts of 2300-3000 (mean 2663) cells/mm2. Surgery was uneventful in all but 2 cases: air entered the EK interface in one and the graft unfolded in the wrong orientation in the other. EK detachments subsequently occurred in 5 cases with successful repositioning in 3. Graft failure (corneal oedema) developed in all 8 cases (primary graft failure (PGF) in 6). Repeat EK (n=3) or PK (n=5) was subsequently performed.Consistent histopathological findings of the corneal buttons were reduction/absence of donor endothelium and reduction of keratocyte density in both donor and host stroma. The graft-host interfaces were inconspicuous. There was no evidence of immunological rejection or inflammation in donor or host material. Varying degrees of retrocorneal fibrous membrane were observed (n=3). Adhesion of donor to host stroma was still observed even in the presence of marked donor endothelial loss.
Conclusions: :
Primary EK failure may be attributed to endothelial decompensation, keratocyte loss and the formation of retrocorneal fibrous membranes, rather than immunological rejection or any inflammatory reaction. Graft adhesion occurred despite the presence of PGF suggesting that donor tissue adhesion does not necessarily depend upon a functioning endothelium.
Keywords: transplantation • pathology: human • cornea: clinical science