Introduction
Keratoconus is a degenerative eye disease. The disease is progressive, causing deformities in the cornea. The cornea is the outermost layer of the eye. In people who have no eye problems, the cornea is clear and dome-shaped. However, in individuals affected by keratoconus, the cornea becomes thinner. It deforms into a cone-like shape, so the light that enters the eye cannot focus accurately on the retina. This change in shape can lead to blurry and distorted vision. Keratoconus can cause symptoms like mild to severe vision loss, blurred vision, nearsightedness, corneal swelling, and scarring. Corneal cross-linking is the most effective and standard treatment for keratoconus.
What Is Keratoconus?
Keratoconus is a rare progressive eye condition that affects the corneas, the transparent layer covering the front of the eye. In individuals affected by this condition, there is a progressive change in the shape of the cornea. The normal corneal surface is smooth and dome-shaped.
Light travels through the cornea, passes the lens to the retina, and then the brain to where the clear image is generated. In individuals affected by keratoconus, the cornea's surface is rough, irregular, and cone-shaped, resulting in a distorted image projected onto the brain. Initially, keratoconus may occur only in one eye, but later, it may affect both eyes, with one eye being more severely affected. Males and females are both equally affected by keratoconus.
The first-line treatment for this condition is using spectacles or contact lenses. However, these measures do not stop the progressive nature of the keratoconus. In severe cases of keratoconus, corneal transplantation is a procedure of choice that helps improve vision. However, this is a complex procedure, and the visual rehabilitation following transplantation could take between 12 and 18 months. It also carries a lifelong risk of corneal graft rejection by the body. In recent times, the advent of corneal cross-linking could delay or stop the progression of Keratoconus.
What Are the Symptoms of Keratoconus?
The symptoms of keratoconus can differ for each individual. In the early stages of keratoconus, symptoms are usually mild and may include:
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Light sensitivity.
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Glare.
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Distorted vision.
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Eye swelling.
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Redness of the eyes.
If swelling occurs due to keratoconus, it can lead to scarring over the corneal tissue, making the cornea opaque and more difficult to see, leading to blurry and distorted vision. In an advanced stage, the symptoms of keratoconus may include:
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Increased nearsightedness.
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Increased vision distortions and blurred vision.
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Contact lens discomfort.
What Is Corneal Collagen Cross-Linking?
Corneal cross-linking (CXL) is a non-invasive treatment for keratoconus as it reinforces the cornea by making new bonds between the collagen fibers in the middle of the cornea. Collagen cross-linking is natural as individuals age from mid-thirties to early forties. The collagen in the cornea tightens through exposure to UV (ultraviolet) sunlight, making the collagen fibers cross-link. The same concept applies to this procedure.
This procedure involves applying a photosensitizing solution to the cornea and exhibiting it to a low dose of UV light. The UV light reacts with the photosensitizer to create new collagen bonds throughout the cornea. These new bonds help to stiffen the cornea, maintain its circular shape, counteract the effects of keratoconus, and allow better vision to be preserved.
Corneal cross-linking is the only treatment option that can halt keratoconus from worsening and reduce the chances of a corneal transplant. Cross-linking may also be used to manage other corneal conditions, such as severe corneal ulcers and ineffective infections against antibiotics.
How Is This Procedure Performed?
Corneal cross-linking is a non-invasive, straightforward procedure performed by an eye care specialist in an operating theater under local anesthesia. In some cases, general anesthesia may be considered. During treatment, the superficial layer of the cornea called the epithelium, is gently removed to allow for better absorption of the photosensitizing agent. Then, photosensitizing drops like riboflavin eye drops are applied every two minutes for 10 to 15 minutes.
After applying photosensitizing drops, the cornea is exposed to a controlled dose of UV light for the next few minutes to produce collagen cross-linking. Once the procedure is complete, the eye is covered with a special bandage soft contact lens to help the epithelium grow back and make the visual recovery quick. This bandage will be left in place until the first review in the hospital. Overall, the procedure takes about 25 minutes.
During the postoperative period, oral tablets will be given for pain relief, and antibiotics and steroid drops will be given to prevent the risk of infection and allow smooth healing. The eye care specialist will examine the eye in a few days. The first visit following the surgery will occur between three and seven days after removing the contact lens.
Recovery After Corneal Cross-Linking for Keratoconus
Immediately after the procedure, the vision may be blurry. As the healing takes place, there may be some changes in the vision. People may sometimes experience poorer vision or be sensitive to light. However, the eyesight should stabilize within one to three months. Dramatic changes in vision tend to occur during the first three months after the surgery. Then, gradually, over up to one year, the cornea tightens and stabilizes, further improving the vision. Proper eye care should be taken following the surgery, such as not rubbing or scratching the eyes for at least a week.
What Are the Possible Complications of Corneal Cross-Linking?
The complications associated with the corneal cross-linking procedure are as follows:
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Infection of the eyes.
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Severe swelling.
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Issues with epithelium healing.
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Pain is due to the removal of the surface of the cornea during the procedure.
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Keratoconus might progress in the future.
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Persistent vision issues.
Conclusion
Keratoconus is a rare eye condition that affects the cornea of the eyes. Eyesight issues like blurry and distorted vision occur due to changes in the shape of the cornea. Corneal cross-linking is an effective treatment for the management of keratoconus. It is an invasive procedure that stops the progression of the keratoconus by strengthening the corneal fibers. It is necessary to consult an eye care professional to determine the proper treatment for the eye disorders.
