Corneal Transplant Surgery
Following disease, infection, or injury, the cornea may become weakened, cloudy, or scarred, leading to decreased vision or discomfort. If medicines, contact lenses, or other treatments are ineffective in improving the symptoms, the damaged cornea can be replaced with a healthy cornea from a donor. At Peninsula Laser Eye Medical Group, Dr. Liu performs four different types of corneal transplants: Descemet’s Membrane Endothelial Keratoplasty, Descemet’s Stripping Automated Endothelial Keratoplasty, Deep Anterior Lamellar Keratoplasty, and Penetrating Keratoplasty. With these different options, Dr. Liu selects the best treatment for his patients to improve vision while minimizing risks. A corneal transplant is the most successful of all tissue transplants: about 48,000 operations are performed in the United States each year.
Descemet’s Membrane Endothelial Keratoplasty (DMEK)
DMEK is specifically suited to treat the damaged inner layer of the cornea (endothelium), which includes patients with conditions such as Fuch’s dystrophy, bullous keratopathy, or failed prior corneal transplants. DMEK involves replacing only the innermost layer of the cornea rather than the entire thickness of the cornea. Because most of the patient’s own cornea remains intact, the results are a smoother corneal surface and faster healing compared to a full-thickness corneal transplant. The replacement tissue is also thinner than DSAEK tissue, which typically allows for better visual acuity after the eye has healed. However, DMEK is also associated with a higher rate of graft detachment and need for graft repositioning. Dr. Liu will help you decide which type of transplant is best for you.
Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK)
DSAEK is also a partial-thickness transplant similar to DMEK. The main difference is the donor tissue, which is slightly thicker for DSAEK. The extra thickness provides the tissue with more structural stability, so the graft is easier to position at the time of surgery. It has a lower rate of requiring an additional procedure, such as repositioning the graft. The final visual acuity may be a little less sharp than with the thinner DMEK tissue, but your vision should still be significantly better than prior to surgery.
Historically, full-thickness corneal transplant surgery has not changed significantly in the last 30 years. A conventional corneal transplant requires long periods of healing, sometimes up to 12 months for patients to enjoy good and stable vision. The traditional corneal transplant procedure requires multiple sutures and a lengthy post-operative recovery period until one reaches their final glasses or contact lens prescription. Now, with the advent of DMEK and DSAEK, we are able to insert a partial thickness corneal transplant through a 4mm (or smaller) incision that typically requires only a single suture and several weeks for recovery of vision.
Benefits of DMEK/DSAEK
- • Stronger corneal integrity with less sutures
- • Smaller incision for faster recovery and rehabilitation
- • Reduced risk of corneal graft rejection
Penetrating Keratoplasty (PKP)
This type of transplant replaces all the layers of the central cornea. This is the best option for corneas that have a significant amount of scarring that cannot be repaired with either DMEK or DSAEK. The new donor cornea is held in place with sutures until it’s fully healed, and they may be adjusted or removed to gradually improve the vision. The overall healing time can take 6 to 12 months. Patients will need glasses and may need to use a contact lens after the transplant has healed for the best vision.
Deep Anterior Lamellar Keratoplasty (DALK)
DALK can be thought of as the opposite of DMEK: it replaces the outer corneal layers while preserving the innermost layer of the cornea. This procedure is most commonly performed to treat advanced cases of keratoconus when the patient is no longer able to tolerate or achieve adequate vision with contact lenses. By preserving the inner layer of the cornea, the risk of corneal graft rejection is lower than a full-thickness transplant, and it also provides a lower risk of surgery and lower risk of infection. Similar to a PKP, sutures are used to hold the graft in place and healing may take upwards to a year.
DALK may only be used for select patients. Because the innermost layer of the cornea is approximately 50 microns, the procedure may need to be converted into a full-thickness corneal transplant.
Corneal tissue for transplantation comes from an Eye Bank. The process begins when someone has been generous enough to donate his or her eyes following their death. The Eye Bank carefully screens the donor cornea to ensure it meets the National Eye Bank Association quality standards. We are fortunate to have several Eye Banks throughout the United States, and there is no waitlist to receive tissue from a donor. The tissue can be stored for several days in a nutrient fluid before its use. The color of the donor eye is irrelevant, since only the clear cornea in the front of the patient’s eye is replaced and not the colored iris behind it. Similarly, tissue typing is not necessary because there are no blood vessels in the normal healthy cornea.
Dr. Jeffrey Liu
Dr. Liu completed a cornea fellowship and is specially trained in corneal transplantation to offer these revolutionary procedures to patients throughout Northern California and the Bay Area.
If you think you may benefit from these procedures or know someone who may need a corneal transplant, please schedule a consultation today with Dr. Liu by calling (650) 961-2585 or schedule online now by clicking this link.