In his letter, Dr Busin suggests that the higher endothelial cell loss seen with the Busin glide in our study may have arisen from the use of a temporal incision, rather than nasal. We had used the Busin glide for 10 months prior to the start of the study. Initially a nasal incision was used, but it was found that a temporal incision provided easier access and allowed combined surgery with phacoemulsification and lens implantation.
Other surgeons have similarly modified Busin’s original technique, including 2 previous studies cited in his letter. Price and associates also used a temporal incision, and showed an endothelial cell loss of 34% at 6 months, not the lower value of less than 30% stated in Dr Busin’s letter. Bahar and associates appear to have used a superior limbal incision and a suture pull-through technique. Of the previous studies cited by Dr Busin, only his own used a nasal incision. The paper by Chen and associates used forceps insertion and not the Busin glide.
A number of possible reasons are acknowledged in our study for the higher endothelial cell loss reported compared to previous studies. There are only 2 reports from the UK reporting postoperative endothelial cell counts (ECC), with losses of 38% and 61%. UK donor corneas are usually preserved in culture medium, rather than Optisol, and the preoperative ECC are taken before the corneas are put into dextran. This is associated with an 8% reduction in donor ECC. Consequently the preoperative ECC would actually be lower, giving a falsely higher-percentage postoperative cell loss.
In addition, the quality of the donor tissue might have influenced the cell loss. The donors used were older and had lower preoperative ECC than those used in some other countries. Older donors and lower donor ECC have been shown to be associated with a greater postoperative cell loss.
Our results show that an experienced DSEK surgeon had almost twice the endothelial cell loss when using the Busin glide compared to the EndoGlide. There is no evidence to suggest that use of a nasal incision would have significantly changed these results.