Abstract
Purpose:
A corneal pre-cutting service for endothelial keratoplasty was developed at the Moorfields Lions Eye Bank in June 2013, leading to a transition from using surgeon-cut to pre-cut tissue. This retrospective review was performed to determine the consistency and quality of the pre-cut tissue. We also aimed to establish techniques that can be used to improve graft quality.
Methods:
We performed a retrospective review of 407 donor corneas pre-cut for endothelial keratoplasty at the Moorfields Lions Eye Bank from June 2013 to November 2014. All corneas were cut with a 350µm Moria microkeratome, using a slow-pass method. Endothelial cell count was determined using specular microscopy, and graft thickness determined with pachymetry. Rates of graft perforation during pre-cutting were also recorded. Initial problems with pre-cut tissue were determined by a simple questionnaire sent to surgeons.
Results:
The perforation rate for the pre-cut corneas was 2.46% (10 of 407) throughout the study period. Perforations occurred during the introduction of the pre-cutting service in June 2013, and also in the initial stages of ultra-thin grafts (<100µm) in May 2014. Mean graft thickness was 162.54µm (76-315, SD 50.9) in 2013, and 81.16µm (48-126, SD 19.8) in 2014. This reflects a continual rise in the number of ultra-thin pre-cut grafts and graft thickness consistency with increasing technician experience.<br /> <br /> Initial problems with the pre-cut corneas were due to loss of cornea markings and eccentric trephination of tissue, which was addressed by introducing cornea re-marking in theatre. Amongst the techniques used to improve the quality of tissue were: air drying (to 500µm or less), clamping the line 2cm from the chamber, lubrication of the blade and corneal surface with basic salt solution, and using a slow six second pass when cutting.
Conclusions:
Our results show that the consistency of successful donor cornea preparation increased from 2013 to 2014, reflecting the learning curve of the technicians. With increasing experience and volume, our Eye Bank is consistently providing us with accurately prepared, high quality tissue.