The cornea is the window of the eye. It is essential for good vision. It helps focus light into the eye, filters harmful ultraviolet rays, and acts as a barrier to prevent harmful matter from entering the eye. Due to its importance for clear vision, diseases that affect the cornea, including injury, genetic, or physiological problems can cause decreased vision or other eyesight issues.
Intermountain Eye Centers provide the most advanced medical and surgical treatment options for disorders of the cornea. This includes the newest types of corneal transplantation and refractive surgery procedures.
Fuchs dystrophy is a slowly progressing corneal dystrophy that affects the corneal endothelium. The endothelium is the thinnest layer of the cornea and functions to pump fluid out of the cornea and keep it clear. In Fuchs dystrophy, endothelial cells are lost at a fast rate and the cornea becomes swollen with fluid. It occurs in both eyes, is more common in women, and usually affects people in their 50’s and older.
Early Fuchs’ dystrophy causes glare and increased light sensitivity. Patients will notice blurry vision in the morning that clears as the day progresses. This occurs because the cornea is thicker in the morning due to our eyes being closed while we sleep. As the disease worsens the swelling increases and can lead to painful blisters on the cornea.
The first treatment usually involves eye drops or ointment. If vision is decreased enough to affect regular every day activities then a cornea transplant may be needed to restore vision. This is one of the most common reasons that someone would need a cornea transplant.
Keratoconus is progressive thinning of the cornea and the most common corneal disorder in the US, affecting one in every 2,000 Americans. It is more prevalent in teenagers and adults in their 20s.
Keratoconus arises when the middle of the cornea thins and gradually bulges outward, forming a rounded cone shape. This abnormal shape changes the cornea’s ability to refract light and can cause severe distortion and blurriness. Sometimes keratoconus is so severe it can cause corneal swelling and scarring that can severely impair vision.
Keratoconus can be inherited, but can also be caused by excessive eye rubbing. It is more common in groups of people who rub their eye frequently including patients with allergies and systemic diseases such as Lebers congenital amaurosis, Ehler-Danlos syndrome, and Down syndrome.
Keratoconus can usually be treated with glasses or special contact lenses. In about 10 to 20 percent of keratoconus patients, the corneal shape is too irregular for any kind of contact and a cornea transplant is required to improve vision. The survival rate of corneal transplant is about 90% in patients with keratoconus.
Collagen crosslinking is a new treatment for keratoconus. It uses riboflavin (Vitamin B2) and UV light to strengthen the cornea. It is like putting steel rebar in concrete to strengthen the wall of a building. With this new treatment, some keratoconus patients may stop having progressive corneal thinning.
If a cornea becomes cloudy, light is unable to penetrate the eye to reach the retina. This can result in decreased vision or blindness. A full-thickness corneal transplant, also known as a penetrating keratoplasty, is done to replace a diseased or scarred cornea with a new one. The transplant is secured to the eye with sutures. Penetrating keratoplasty is safe and a very common form of corneal tranplant, with over 20,000 being performed every year in the United States.
DSAEK, Descemet’s Stripping Automated Endothelial Keratoplasty, is a partial thickness corneal transplant. Unlike a conventional corneal transplant surgery, DSAEK uses a smaller incision, and stitches aren’t necessary. For this reason, patients usually experience faster recovery and have less follow-up visits. During the procedure, the surgeon uses special instruments to enter the eye through an incision less than ¼ inch long. The back portion of the cornea is then replaced by a similar piece of healthy graft tissue from a donor. DSAEK is not for all patients with corneal disease, but is the standard procedure for diseases of the corneal endothelium. It is the most common corneal transplant performed in the United States.
Descemet’s Membrane Endothelial Keratoplasty (DMEK) is the thinnest and newest type of cornea transplant available for diseases requiring a partial-thickness cornea transplant. For comparison, a DMEK is 1/6 of the thickness of a DSAEK corneal transplant. As compared to traditional full-thickness corneal transplants, this procedure has a quicker recovery time and vision improvement. Additionally, there is a lower risk for transplant rejection with this type of transplant. If your inner corneal layer is swollen and not working properly, you may be a candidate for DMEK.
Deep Anterior Lamellar Keratoplasty (DALK) is another partial-thickness corneal transplant. In a DALK surgery, the endothelial layer (back layer) of the cornea is left intact, and only the outer layers of the cornea are replaced with donor tissue. Compared to penetrating keratoplasty, DALK has a lower risk of graft rejection. DALK is usually offered to certain patients with keratoconus