donor graft quality used for penetrating keratoplasty versus deep anterior lamellar keratoplasty

deep anterior lamellar keratoplasty (dalk) has recently been introduced as an alternative procedure to penetrating keratoplasty (pk) for corneal pathologies not affecting the corneal endothelium. dalk does not rely on donor endothelium and requires less rigid criteria for donor corneal tissue quality. therefore, dalk makes it possible to use donor corneas deemed unsuitable for pk. furthermore, lamellar keratoplasty allows acellular corneal tissue to be transplanted. as a result, long-term preservation techniques are being revisited to increase the availability of donor corneas and subsequently alleviate constraints of availability, cost, storage, and transportation in many countries. the recent alterations in corneal transplantation techniques and hence the type of donor cornea tissues used for each technique, may require corneal surgeons and eye banks to reevaluate their selection criteria. the purpose of this systematic review is to present an updated analysis on the type and quality of donor corneas used for pk and dalk, assess the influence of donor and eye bank factors on the quality of donor corneas, and determine whether any of these donor factors affect clinical outcomes, complications, and graft survivals.