DMEK
DMEK
What is DMEK?
Descemet membrane endothelial keratoplasty (DMEK) is the newest version of endothelial keratoplasty to treat swollen corneas as seen in Fuchs dystrophy, bullous keratopathy, and other causes of poor corneal endothelial function. DMEK surgery provides the most anatomically exact replacement of the diseased layer of the cornea and leaves the patient’s cornea closer to its original condition more than any other corneal transplant technique. DMEK surgery is technically advanced and involves the transplantation of just one cell layer on a thin 15-20 micron thick membrane.
What at the advantages of DMEK compared to standard corneal transplantation?
- The eye surface is kept intact with faster and better visual recovery
- There is usually only a very small refractive shift because only the very inner layer of the cornea is replaced
- Usually only 1-2 sutures are necessary to close the incision sites (which are removed a month later in clinic)
- Because it does not include other layers of the cornea, studies have shown that it offers a lower rejection rate compared to other techniques
- There is flexibility with the surgical plan as DMEK can be staged after cataract surgery, combined cataract surgery or done prior to cataract surgery depending on your age and lens/cataract. Your cornea surgeon will tell you what is best in your case.
How is the thin corneal graft attach to my cornea?
The tissue is so thin that sutures cannot be used to attach the graft. Instead a gas or air bubble is placed into the eye to gently float the graft into the upward correct position. That is why your corneal surgeon will have you position on your back with your eyes straight upwards after your surgery. Because gas floats above liquid, the gas pushes upward and allows your new cornea transplant to attach to the inner side of your own cornea.
What is the difference between DSAEK and DMEK?
DSAEK is very similar to DMEK except that DMEK is an even thinner tissue. It dose not include any of the cornea stroma. Instead it includes the very inner layer of Descemet's Membrane and endothelial cells. On average vision may be slightly sharper than DSAEK, however post operative detachments requiring additional air or gas into the eye are more common.
Preparing for DMEK Surgery
Do not eat or drink after midnight prior to your surgery. Any needed medications can be taken with a small sip of water. It is important to continue taking the medical eyedrops (e.g. for glaucoma) that you would normally use on the same day of surgery.
The Surgery
The procedure is done through a small incision on the side of the cornea and usually takes about 45 minutes to complete if done alone or 60 to 90 mins if done in conjunction with a cataract surgery. The DMEK procedure involves removing the diseased endothelial layer from the back of the cornea and leaving the healthy remainder intact. The donor corneal tissue is then placed into the eye through the small incision and is positioned into place. Once in good position, your surgeon then locks it into place with the injection of a small gas bubble
Post-operative care
The eye is patched and minimal discomfort should be experienced. Tylenol (acetaminophen) can be taken, as needed. As much as possible, you should lie down on your back, facing the ceiling for the first 24 hours. We require you not to look downward past eye level. You will see the doctor the same or the next day after your surgery. Your patch will be removed and your eye examined. You will be instructed on when to start an antibiotic and steroid drop to prevent infection and aid in healing. Your next appointment will be in approximately 1 week after surgery and usually in 3-4 weeks afterwards. Vision usually starts to recover by week 2-3 after surgery. Glasses are dispensed around 2-3 months after surgery once vision has completely stabilized.
Click Here for more information on post-operative care for DSAEK and DMEK surgery.
DMEK Detachment
This can happen any time from the day after surgery to the week afterwards. After a week it is very rare to have a late detachment. If the cornea has a small detachment, your surgeon will replace additional air in the minor procedure room or clinic room to allow for better attachment. The need to replace additional air occurs in ~ 10-15% of DMEK surgeries. Usually once positioned with air, vision will be very blurry until the air is reabsorbed, afterwards vision is restored. If the cornea cannot be completely attach after 1-2 rebubblings, then your surgeon will replace your donor cornea with a new in the operating room several weeks later.
DMEK graft week one
For a video on the DMEK procedure, Click Here.