Descemet's stripping automated endothelial keratoplasty grafts

DSAEK (Descemet's stripping automated endothelial keratoplasty) grafts are demonstrating good visual results and long-term survival rates despite high endothelial cell count loss, according to William Power MD, FRCOphth, Royal Victoria Eye and Ear Hospital (RVEEH), Dublin. DSAEK has been performed for more than five years, meaning surgeons have access to medium-term outcomes data. It is a superior option to penetrating keratoplasty (PKP), he told the Joint Irish and UKISCRS refractive surgery meeting. Listing the advantages of using DSAEK, Dr Power said it provides stable refraction and a quick visual rehabilitation, intact innervation, a stronger wound, retention of corneal integrity, no suture-related complications and less problems with ocular surface healing.

Additionally, two grafts can be obtained from one donor cornea. Vision improves quite quickly after DSAEK with notable improvement after one month Dr Power said, quoting a study of 16 of his original DSAEK patients with four-tofive- years of follow-up. “After three months most patients are experiencing a significant improvement so you are getting a very quick recovery in terms of vision. Between one and three months most patients achieve their new level of vision and maintain a fairly stable level following that. This is a huge advantage to the patient,†he explained, adding these results are very different from what is usually seen with PKP. Dr Power highlighted potential severe complications of PKP such as suture problems, endophthalmitis and expulsive haemorrhage.

“Certainly every two to three years in our institution we would see a ruptured graft from some sort of accidental trauma. And of course these things are avoided by DSAEK.†He said while the disadvantages of DSAEK “aren’t major†there is an increased primary failure, “which can be very frustrating especially after what seemed like a very smooth procedureâ€. There can also be issues with donor dislocation, interface haze and of course there remains question marks over long-term graft survival. Without doubt there is significant cell loss in the initial period following DSAEK, ranging from 25 per cent to 45 per cent in our study. “Thus a very important point is that you give the patients as many cells as you can,†Dr Power said. For example, using a 9.0mm graft compared to an 8.0mm one means there is a 27 per cent increase in total cell count delivered to the patient, he said.

“What has surprised a lot of people is that so many of the grafts are clear but if we do cell counts it seems to be quite low. We may be able to keep these grafts clear with a smaller number of healthy cells in the presence of a more normal intact Descemet’s membrane. Cell loss is highest in the first three to six months but it plateaus out then. The key is to minimise the cell loss in the operative period and if you can do that then the long-term survival of grafts should be good,†Dr Power told EuroTimes.