Tuesday, January 27, 2009
Dr. Yiu provides an update on a variety of anterior segment issues in a conversation with Dr. Brian Francis.
The DMEK procedure: DMEK = Descemet’s membrane only, no stromal tissue. It is relatively new with few surgeons actually skilled in the technique. At Doheny, they’ve done nearly 200 cases. Tissue preparation for the DMEK is more challenging in that eye banks do not prepare the tissue in the same way they do donor corneas for DSEK. Penetrating keratoplasty with the IntraLase femtosecond lasers is being done at Doheny also (IEK, IntraLase Enabled Keratoplasty). In the first 9 cases they have done, the astigmatic changes compared to traditional corneal transplant is much smaller. This is because of the precision of the cut. IEK has the advantage of preparing donor and recipient tissues identically and allows for the tissue to be joined mechanically using a zigzag pattern, akin to an interlocking puzzle piece. Also reduces the time required for sutures to remain in the tissues. This allows for greater strength of the cornea once healed.
Dry Eye Therapy: Restasis (topical cyclosporine)has been the only option since 2004. However several new drugs are in the pipeline and offer some encouraging data. Dicrovazole, a p2-i2 agonist, affects the tear film by increasing production of mucin and oily layers of tear film. Another presented had dual action: lubricating and penetrate deep into epithelium for extended duration. Artificial lachrymal gland project: an implantable of live tissue on biocompatible scaffold to enable patients to secrete more tears. Azasite, azithromycin, may impact the Meibomian gland positively and offer some relief – more work needs to be done here.
Graft rejection in corneal transplant: Use of topical drugs has not been found to be efficacious. At Doheny, a more aggressive triple therapy approach is in use. They are also one of the sites evaluating the Lux Biosciences cyclosporine implant which offers sustained release for one year. Preliminary data are encouraging. Topical avastin may aid in reduction of neovascularization, implicated in corneal graft rejection.