Lamellar keratoplasty rising, but advances needed to improve outcomes

Selective lamellar keratoplasty, both endothelial and anterior, is taking hold around the world and is almost certainly the future of corneal transplantation, 2015 Binkhorst Medalist Donald TH Tan FRCS, Singapore, told the opening session of the 2015 American Society of Cataract and Refractive Surgery Symposium.

But while endothelial keratoplasty has become the gold standard for treating endothelial dysfunction, loss of endothelial cells remains a challenge, Dr Tan observed. Advances in surgical technology and technique are improving cell survival rates, which should lead to better long term outcomes.

For example, with the DSAEK taco folding tissue insertion technique, six month endothelial cell loss was above 60 per cent in Asian eyes in 2006, Dr Tan reported. Switching to sheets glide cut that to about 30 per cent in 2007, and the EndoGlide inserter, developed by Dr Tan and colleagues, cut that to about 15 per cent – less than the 20 per cent seen with penetrating keratoplasty. “We have managed to halve our endothelial cell loss in DSAEK with each insertion transition.”

With its extremely thin and fragile donor tissue, DMEK presents new challenges, Dr Tan said. The tissue is difficult to manipulate and touching it destroys endothelium. Even the masters of the technique see endothelial losses of 34 to 40 per cent. The newly developed D-Mat for use with the EndoGlide may make the membrane easier to handle, and help reduce cell loss and donor tissue waste, he said.

Similarly, deep anterior lamellar keratoplasty has proven superior to penetrating keratoplasty in both visual and graft survival outcomes. Yet the surgery itself is technically challenging, prompting many to seek new solutions. Indeed, some have moved away from the “big bubble” lamellar separation technique, which can result in accidental perforations, to manual blunt dissection, Dr Tan said.

But manual dissection, too, remains more art than science, Dr Tan said. Possible technological solutions include microkeratomes and femtosecond laser, but these also have their limits. Dr Tan is experimenting with a piezo-electric vibrating blunt dissector to ease manual dissection. So far it is producing very smooth separations of deep corneal lamellae, he reported.

“Major surgical challenges remain and technological changes are needed. They will hopefully come soon,” Dr Tan concluded.

After the lecture ASCRS Programme Committee Chair Edward J Holland MD presented Dr  Tan with the 2015 Binkhorst Medal in honour of Dr Tan’s career contributions to ophthalmology.