Ocular Tissue Banking

Abstract

Disease and trauma can cause loss of corneal transparency or distortion of corneal shape, resulting in severe visual impairment. For many of these patients, the only option to restore vision is a corneal transplant where clear, healthy tissue from a deceased eye donor is used to replace the diseased tissue. Corneal transplantation is one of the oldest and most frequently performed transplant operations with at least 180 000 procedures annually worldwide. Hypothermic storage allows corneas to be kept for up to two weeks. Alternatively, organ culture at 28–37 ℃, allows up to four weeks of storage. For the great majority of transplants, a healthy corneal endothelium is required. These cells do not readily proliferate in situ and there is a gradual decline in endothelial cell density throughout life. The endothelial cell density is therefore one of the principal quality assessment criteria used by eye banks. Full-thickness corneal transplantation (penetrating keratoplasty) has in many cases been superseded by techniques where only the diseased part of the cornea is replaced. Endothelial keratoplasty, where the graft comprises endothelium supported only on its basement membrane with or without a thin layer of corneal stroma, is now the method of choice for endothelial deficiency. Stromal opacities can be treated with transplants of stromal tissue without the endothelium, retaining the patient’s own healthy endothelium. Sclera and limbal tissue are used, respectively, for reconstructive surgery and for treating ocular surface disease.