Keratoconus is a condition that affects the cornea, which is the outermost part of the eye. The transparent, dome-shaped cornea helps to protect the eye, but it also functions as a lens to focus incoming light onto the retina to provide clear vision. The cornea’s thickest layer, called the stroma, contains collagen. Collagen is a type of protein that is abundant in the body. It consists of tightly packed molecules that form long, thin fibers that give strength and structure to cells and tissue.
In eyes that develop keratoconus, the corneal collagen becomes unstable. This causes the cornea to become weaker and thinner and to bulge forward, creating an irregular cone-like shape. With the natural shape of the cornea altered, vision is affected. The first symptoms associated with keratoconus, which may include slight blurring or distortion of vision and increased sensitivity to light, may be mild. However, the condition is progressive, which means without treatment it worsens over time. Symptoms may advance to include starbursts around lights, ghosting, multiple images, intense glare or severe blur and distortion. Keratoconus tends to first appear in individuals in their late teens or early 20s. In some eyes, it may progress for many years and then stabilize. In others, approximately 10-20% of keratoconus sufferers, it may eventually reach a point at which a corneal transplant is necessary to restore useful sight.
The cause of keratoconus isn’t completely understood. It’s thought that the condition could be related to genetics, hormones, insufficient elimination of cell metabolism byproducts from the body, atopic (allergic) disease, or a combination of factors.
The FDA recently approved a new treatment for keratoconus called corneal collagen cross-linking (also known as KXL). KXL isn’t a cure for keratoconus, but it’s the first treatment that’s capable of stopping its progression, preventing the need for a corneal transplant. A large number of studies have shown that KXL prevents further loss of vision for most patients and improves vision for many.
While KXL is newly approved for use in the United States, it has been performed on more than 200,000 eyes around the world.
KXL can be performed in the cornea specialist’s office. Most patients only require one treatment.
The treatment, which is painless, is done while you are lying on your back. Drops will be used to numb your eye, and you’ll be given a mild sedative like a Valium tablet. You’ll be asked to look at a soft light above your head throughout the treatment. KXL takes approximately an hour for one eye. For the first 30 minutes, a drop of a riboflavin (vitamin B2) solution will be placed into your eye every few minutes. The riboflavin is then activated by exposing it to an ultraviolet (UV) light for 30 minutes. During the activation time, riboflavin drops are again placed into your eye every few minutes. This process creates new collagen cross-links (bonds) in the stroma and results in a shortening and thickening of the collagen fibers, which stiffens and strengthens the cornea. At the end of the treatment, a contact lens will be placed on your eye to protect it like a bandage.
After KXL, your vision may seem worse for a few weeks. Around week four, you should begin to notice some improvements. Further improvements can occur over several months. Like any medical procedure, KXL can produce side effects, which your doctor will discuss with you. Most of the potential side effects disappear within a month, while others may take longer to go away. Some patients feel eye discomfort or as if something is in the eye after the procedure. The eye may feel sensitive to light. (Wearing sunglasses can help.) If you feel severe eye pain or have a sudden decrease in vision, or if the bandage contact lens falls out or becomes dislodged, call your eye doctor immediately. Your doctor will also discuss with you whether you can return to your usual activities the next day or whether you’ll need to wait a few days. If you were wearing glasses or contact lenses to correct your vision prior to KXL, you may or may not have to continue wearing them, or have them updated, after the recovery period.
Most patients who have keratoconus can be helped by KXL. However, there are other ways for patients with the condition to achieve good vision before having KXL or needing a corneal transplant.
Specially designed rigid gas permeable contact lenses are an effective option. And, thanks to the development of new contact lens materials, soft contacts may work as well. Hybrid contact lenses, rigid in the center and soft around the edges, are also available, as are scleral lenses, which have a large diameter, rest on the white of the eye, and vault above the cornea. A rigid lens worn on top of a soft lens is also sometimes done.
A surgical option that has shown effectiveness for keratoconus is the implantation of small semi-circular inserts into the cornea, which helps to normalize its shape.
For patients who must undergo a corneal transplant, improvements to the procedure, in particular the use of a highly advanced femtosecond laser, have improved results in recent years. The laser can be programmed to create precisely shaped incisions in the patient’s cornea and in the donor corneal tissue. This produces many benefits, including faster healing, a more stable cornea, and better postoperative vision.
If you suffer from keratoconus, contact Barnet Dulaney Perkins Eye Center at (602)-955-1000. We have practices throughout Arizona, including Phoenix, Tucson and Flagstaff. We’ll schedule a consultation for you so you can learn how to achieve your best possible sight.