We Pursue Eye Research
Corneal Transplants
Endothelial Keratoplasty (EK)
Endothelial keratoplasty is the preferred way to restore vision when the inner cell layer of the cornea stops working properly from Fuchs’ dystrophy, bullous keratopathy, iridocorneal endothelial (ICE) syndrome, or other endothelial disorders. EK selectively replaces only the diseased layer of the cornea, leaving healthy areas intact.
Dr. Price, founder and president of the Cornea Research Foundation, was an early pioneer of this procedure. Since 2002 he has been taught courses in this transplant technique to over 500 doctors from 23 countries around the world and he has performed over 1600 EK procedures, more than any other surgeon in the world.
In the EK procedure, the surgeon removes the diseased inner cell layer of the cornea (Figure 1) and implants healthy donor tissue through a small incision (Figure 2). An air bubble is used to unfold and position the donor tissue against the patient’s cornea (Figure 3). The small incision is either self-sealing or may be closed with a few sutures. Dr. Price routinely performs this procedure just using eye drops to numb the eye.
Compared with a traditional full thickness transplant, endothelial keratoplasty provides the following advantages:
- The eye remains much stronger and less prone to injury
- Visual recovery is much faster
- Minimal activity restrictions are required
- Minimal change is required in glasses prescription
DSEK and DSAEK techniques
The most common type of EK procedure is known as DSEK or DSAEK. In this procedure the surgeon implants the back 20-30% of the donor cornea into the patient’s eye. Patients without other eye problems usually achieve average vision of 20/30 or better within a couple of months. Drs. Francis and Marianne Price produced the first ever DSEK book, describing how the procedure is done and what it is like from the patient’s perspective.
News Story: Dr. Price yields positive visual outcomes in keratoplasty. Read Story
DMEK and DMAEK techniques
Dr. Price is helping to pioneer newer forms of EK, known as DMEK or DMAEK. These use extremely thin donor tissue and provide more patients with 20/20 or 20/25 than DSEK or DSAEK. In fact, DMEK and DMAEK provide 20/25 or better vision for about 3 out of 4 patients.
The biggest hurdle with DMEK is the preparation of the donor tissue. Basically the endothelium and attached Descemet’s membrane has to be peeled off the back of the donor cornea. The ultra-thin DMEK grafts are so fragile that sometimes the precious donor tissue tears while separating the layers and it cannot be salvaged. Descemet’s membrane is only about 15 microns thick! So the preparation has to be done very carefully.
Once a DMEK graft is placed into the patient’s eye, it usually curls up into a scroll. The scroll has to be unrolled and the surgeon has to determine which side should face the recipient cornea and which side should face the inside of the eye. We have developed some techniques to help with this, but it is still a complex surgery for the surgeon. As a result, we have evaluated some hybrid techniques like DMAEK.
In DMAEK the donor graft just has the thin Descemet’s membrane and endothelium in the center, with an outer rim of extra supporting tissue which is the thickness of a DSEK / DSAEK graft. The outer ring of thicker tissue prevents the graft from curling into a scroll and allows easier placement of the tissue in the patient’s eye. Pavel Studeny in the Czech Republic came up with the idea of this hybrid technique, but he uses a hand dissection to remove the anterior stroma from the donor eye. In the DMAEK technique, we remove the anterior stromal tissue from the donor with a microkeratome just as we do in DSEK / DSAEK surgery. Next we turn the donor tissue over and inject air into the tissue to separate Descemet’s membrane from the rest of the donor over the central 5 to 7 mm of the cornea. We then coat the endothelium with a special viscoelastic material to protect it, remount it on an artificial anterior chamber and remove the stromal tissue over the area where the Descemet’s membrane was removed by the air. We now have the DMAEK graft ready to be punched or cut with a round trephine to the sized needed for the patients eye – just as is done for a standard penetrating keratoplasty or DSEK / DSAEK. Just as in DMEK, DMAEK surgeries require more re-injections of air to keep the thin donor tissue up against the back of the patient’s cornea during the first few days to weeks after surgery compared to DSEK / DSAEK. The ultimate reward is the excellent vision that these patients achieve.
Our Endothelial Keratoplasty Publications (DSEK, DSAEK, DMEK and DMAEK)
{exp:list_maker type=“ol”}Price MO, Price DA, Fairchild KM, Price FW. Rate and risk factors for cataract formation and extraction after Descemet stripping endothelial keratoplasty. Br J Ophthalmol, in press.
Kwon RO, Price MO, Price FW, Ambrosio R, Belin MW. Pentacam characterization of corneas with Fuchs’ dystrophy treated with Descemet membrane endothelial keratoplasty (DMEK). J Refract Surg 2009, in press.
Price FW, Price MO. Spontaneous clearance despite graft detachment in DMEK. Am Jour Ophthalmol 2009, in press.
Price MO, Price FW. Endothelial keratoplasty. Clinical and Experimental Opthalmology 2009, in press.
Price MO, Bidros M, Gorovoy M, Price FW, Benetz BA, Menegay HJ, Debanne SM, Lass JH. Effect of incision width on graft survival and endothelial cell loss after Descemet stripping automated endothelial keratoplasty. Cornea 2009, in press.
Price MO, Gorovoy M, Benetz BA, Price FW Jr, Menegay HJ, Debanne SM, Lass JH. Descemet’s Stripping Automated Endothelial Keratoplasty Outcomes Compared with Penetrating Keratoplasty from the Cornea Donor Study. Ophthalmology. 2009 Dec 22. [Epub ahead of print]
Price MO, Giebel AW, Fairchild KM, Price FW. Descemet’s membrane endothelial keratoplasty: prospective multicenter study of visual and refractive outcomes and endothelial survival. Ophthalmology 2009;116:2361–2368.
McCauley MB, Price FW, Price MO. Descemet membrane automated endothelial keratoplasty: hybrid technique combining DSAEK stability with DMEK visual results. J Cataract Refract Surg 2009;35:1659-64.
Vajaranant TS, Price MO, Price FW, Gao W, Wilensky JT, Edward DP. Visual acuity and intraocular pressure after Descemet’s stripping endothelial keratoplasty in eyes with and without preexisting glaucoma. Ophthalmology 2009;116:1644-50.
Price FW, Price MO. Does endothelial cell survival differ between DSEK and standard PK? Ophthalmology 2009;116:367-8.
Price MO, Jordan CS, Moore G, Price FW. Graft rejection episodes after Descemet stripping with endothelial keratoplasty: part two: the statistical analysis of probability and risk factors. Br J Ophthalmology 2009;93:391-5.
Jordan CS, Price MO, Trespalacios R, Price FW. Graft rejection episodes after Descemet stripping with endothelial keratoplasty: part one: clinical signs and symptoms. Br J Ophthalmol 2009;93:387-09.
Price MO, Price FW, Stoeger C, Soper M, Bavuso T, Locke G. Central thickness variation in precut DSAEK donor grafts. J Cataract and Refract Surg 2008;34:1423-4.
Price MO, Baig KM, Brubaker JW, Price FW. Randomized, prospective comparison of precut vs surgeon-dissected grafts for descemet stripping automated endothelial keratoplasty. Am J Ophthalmol 2008;146:36-41.
Price FW. Precut tissue for descemet stripping automated endothelial keratoplasty. Cornea 2008; 27: 630-1.
Vajaranant TS, Price MO, Price FW, Wilensky JT, Edward DP. Intraocular pressure measurements following Descemet stripping endothelial keratoplasty. Am J Ophthalmol 2008;145:780-6
Price FW, Price, MO. Adult keratoplasty: has the prognosis improved in the last 25 years? Ophthalmology International, 2008; 28:141-146.
Price MO, Price FW. Endothelial cell loss after descemet stripping with endothelial keratoplasty influencing factors and 2-year trend. Ophthalmology. 2008;115:857-865.
Allan B, Terry MA, Price FW, Price MO, Griffin N, Claesson M. Corneal transplant rejection rate and severity after endothelial keratoplasty. Cornea 2007; 26:1039-42.
Price MO, Price FW. Descemet’s stripping endothelial keratoplasty. Current Opinion in Ophthalmology 2007; 18:290-4.
Price MO, Price FW. Descemet stripping with endothelial keratoplasty for treatment of iridocorneal endothelial syndrome. Cornea 2007;26:493-497.
Price MO, Price FW, Trespalacios R. Endothelial keratoplasty technique for aniridic aphakic eyes. J Cataract and Refract Surg 2007; 33:376-379. {/exp:list_maker}
