Paul M. Phillips, M.D., a board certified ophthalmologist, is performing corneal transplants at Jameson Hospital. Dr. Phillips attended the University of Cincinnati College of Medicine, Cincinnati, Ohio and served an internship at Mercy Hospital, Pittsburgh, PA. His ophthalmology residency was at the University of Virginia School of Medicine, Charlottesville, Virginia. He served his cornea specialist fellowship at the Devers Eye Institute, Portland, Oregon.
In corneal transplant, also known as keratoplasty, a patient's damaged cornea is replaced by the cornea from the eye of a human cadaver. This is the single most common type of human transplant surgery and has the highest success rate. The cornea is the transparent layer of tissue at the very front of the eye. It is composed almost entirely of a special type of collagen and normally contains no blood vessels, but because it contains nerve endings, damage to the cornea can be very painful.
In a corneal transplant, a disc of tissue is removed from the center of the eye and replaced by a corresponding disc from a donor eye. The circular incision is made using an instrument called a trephine. In one form of corneal transplant (penetrating keratoplasty), the disc removed is the entire thickness of the cornea and so is the replacement disc. Over 90% of all corneal transplants in the United States are of this type. In lamellar keratoplasty, on the other hand, only the outer layer of the cornea is removed and replaced. Eye banks acquire and store eyes from donor individuals largely to supply the need for transplant corneas.
Dr. Phillips attaches the donor cornea with extremely fine sutures. Topical anesthesia is applied and drops for relaxation and requires ten minutes. Over 40,000 corneal transplants are performed in the United States each year.
A less common but related procedure called epikeratophakia involves suturing the donor cornea directly onto the surface of the existing host cornea. The only tissue removed from the host is the extremely thin epithelial cell layer on the outside of the host cornea. There is no permanent damage to the host cornea, and this procedure can be reversed. It is usually employed in children. In adults, the use of contact lenses can usually achieve the same goals.
Descemet's Stripping Endothelial Keratoplasty (DSEK)
A new form of corneal transplant called Descemet's Stripping Endothelial Keratoplasty (DSEK) is a procedure that improves vision for patients with certain types of corneal diseases that cause clouding of the front, clear part of the eye (Fuchs Endothelial Dystrophy, Pseudophakic Bullous Keratopathy).
Comparison of Different Types of Corneal Transplant Procedures
The cornea is the front clear part of the eye. Corneal clouding (edema) most frequently occurs because of loss of the "endothelial" cells that line the inside of the cornea. In this diagram of a healthy eye, these endothelial cells are shown as a blue line on the inside of the cornea.
A cloudy, swollen cornea develops when there are too few endothelial cells. The black arrows show the area where an incision is made in a conventional corneal transplant.
Penetrating Keratoplasty (PKP),
Conventional Corneal Transplant Surgery
In conventional corneal transplant surgery (called penetrating keratoplasty), the surgeon removes the window of cloudy tissue from the patient's cornea and replaces it with donated tissue from a cadaver. This new tissue is held in place with many tiny stitches. To allow healing, these stitches must remain in place for at least six months. Then they are usually removed slowly over several office visits. During this time, vision is usually very poor, and the stitches may cause discomfort. Even after all stitches are removed, vision may not return to normal because of warping or 'irregular astigmatism' that remains in the corneal graft.
Descemet's Stripping Endothelial Keratoplasty (DSEK)
In DSEK, the surgeon uses special instruments to enter the eye through a less than 1/4 inch incision in the front clear part of the eye (cornea). The back portion of the cornea (Descemet’s membrane) is then painlessly stripped away and replaced by a similar piece of healthy graft tissue from a cadaver donor. Although only a small piece of cornea is actually replaced, the graft will help keep the entire cornea clear.
DSEK has several advantages over conventional transplant surgery.
No stitches are placed in the cornea. In clinical studies, this has resulted in significantly less astigmatism after surgery and faster recovery of vision.
In general, fewer follow-up exams are necessary because there are no corneal stitches to be removed. Ongoing studies are also examining whether corneal transplant rejection is less likely with DSEK than conventional transplants.
Like conventional transplantation, DSEK surgery is covered by most major insurance carriers, including Medicare. DSEK is not appropriate for all patients with corneal disease.
Cataract Surgery and Intraocular Lens Implants (IOL) are one of the most frequently performed types of eye surgery. Cataract operations to restore vision after Cataract Surgery is performed by implanting tiny, permanent artificial Intraocular Lens Implants or IOLs to achieve vision correction after surgery. Lens Implants are manufactured from flexible and foldable materials allowing cataract surgeons to implant or “inject” them through very tiny incisions so small that do not require stitches or sutures to close the incision. The short recovery time after Cataract Surgery allows patients to resume everyday activities within a day or so after the Cataract procedure.
Cataract Surgery is usually performed using a microsurgical technique called “phacoemulsfication” whereby the Cataract is gently “chopped up” and “suctioned” to remove it. There are many technological advances in Phacoemulsification that have enabled skilled Cataract Surgeons to perform Cataract Surgery and provide Lens Implants through very tiny incisions requiring only eye drops, rather than needles or injections for anesthesia and without the need for stitches or a patch after the surgery. This allows patients to have a very quick visual recovery. Patients have the comfort and convenience of having cataracts removed in an outpatient hospital setting.