Descemet's membrane endothelial keratoplasty (DMEK) is our treatment of choice for patients who need an endothelial keratoplasty. This partial-thickness transplant is performed in most cases of Fuch’s corneal dystrophy and bullous keratopathy, however very complicated surgical cases may require a DSEK. Some major advantages of DMEK over DSEK is the decreased risk of tissue rejection and superior visual acuity after tissue healing. Post-operatively, patients undergoing DMEK can achieve 20/20 vision, and can even be considered a candidate for a multifocal IOL implant in some cases.
Descemet’s stripping endothelial keratoplasty is another method of endothelial transplantation. While a DMEK transfers the endothelial layer alone, a DSEK will strip a small layer of the stroma in addition to the damaged endothelial layer, and the transplanted tissue will also include a small layer of stroma. The host-stroma to donor-stroma interface can cause a small hyperopic shift, as well as a slight reduction in visual acuity after the cornea is healed and stable. This procedure is reserved for patients with complicated anterior chambers that could include tube shunts, anterior chamber IOLs and other complex anterior chamber findings. While some patients can achieve 20/20 vision post-DSEK, the majority are 20/25 or 20/30 post-operatively.
Vance Thompson Vision has been involved with corneal cross-linking since 2011 through our participation in the clinical trials leading up to FDA approval. Corneal cross-linking is a corneal procedure that is indicated for patients with progressing ectatic conditions like keratoconus and post-LASIK ectasia. Currently, we are performing epithelium-off corneal cross-linking, as it is both the approved method by the FDA, as well as greater efficacy in corneal stability compared to transepithelial (also known as epithelium-on corneal cross-linking) methods. During the procedure, the epithelium is loosened and removed, followed by exposure to UV light and riboflavin. The combination of the UV light and riboflavin enhances the strength of the corneal stroma by inducing covalent bonds between the corneal collagen fibers.
Phototherapeutic keratectomy is indicated on corneas with irregular corneal surface, like anterior basement membrane dystrophy or anterior stromal scars. Prior to PTK, the only way to remove anterior scarring of the cornea was via a full-thickness corneal transplant. The surface epithelium is loosened and removed, then a laser is utilized to remove any anterior stromal scars. The laser also improves the ability of the new epithelial cells to grow back in a more smooth and regular fashion. Due to the removal of the epithelial cells, a bandage contact lens is applied to the ocular surface to promote patient comfort and protect the new epithelial cells. The lens is removed around 4-5 days after the procedure, and vision will continue to improve over the following 1-2 weeks. Our very own Dr. Vance Thompson was a national medical monitor in the FDA-controlled clinical trials during the development of PTK in the United States in 1995.