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We thank Drs Stoeger and Terry for their interest in our article, and we appreciate their comments on the quality assessment of precut tissue for Descemet stripping automated endothelial keratoplasty (DSAEK) performed in the eye bank. We agree with most of their points, including the fact that the clinical outcomes and dislocation rates are mainly related to the surgical technique used to perform DSAEK. The number of donor cells that survive the transplant procedure depends on the donor preparation and particularly on the extent of trauma related to tissue manipulation during surgery.1 In order to maximise results, we included a minimum donor density of 2500 cells/mm2 for precut tissue, to address two key points: assessment of endothelial cell mortality after microkeratome cut and surgeon's technique used for DSAEK.
The use of a vital stain (Trypan Blue) is a simple procedure to highlight endothelial cell mortality.2 However, this dye only partially assesses endothelial cell death because it does not stain apoptotic cells.3 In our opinion, it is important to consider this ‘underestimation’ of endothelial cell mortality related to the stress on the corneal tissue occurring during the cutting process (eg, microkeratome blade or artificial anterior chamber dismounting). For the second point, although the DSAEK surgery is not technically any more challenging than penetrating keratoplasty,4 the influence of the surgeon's learning curve and donor lenticule insertion technique can make a difference to the clinical outcome.5 DSAEK surgery, and especially the use of precut tissues, has clearly shown an increasingly positive trend in recent years. We believe that the possibility of providing donor tissues with a minimum density of 2500 cells/mm2 may improve the clinical outcomes for surgeons performing DSAEK during their learning curve.6
In conclusion, we thank again Drs Stoeger and Terry for their pertinent comments on our investigations. We agree with them that eye banks play an important role in providing both precut and ‘non-precut’ tissues for DSAEK surgery. Eye banks can ensure the quality of posterior lamellar discs and minimise tissue wastage.