Corneal Collagen Cross-Linking with Riboflavin and UV-A light (UVX)

 Keratoconus is a disorder of the eye which results in progressive thinning of the cornea and ultimately causes the cornea to weaken and bulge outward. This abnormal curvature of the cornea is often in the lower half of the cornea and initially leads to astigmatism. Of course, It should be noted, however, that all cases of astigmatism are not due to keratoconus. In mild cases or in the early stages of keratoconus, eyeglasses can be worn to correct the astigmatism. So far, there has not been a treatment for slowing down the progression of keratoconus in the world. All treatments such as eyeglasses, contact lenses, intrastromal corneal ring segment have helped to correct only a part of the patient's vision.

Fortunately, in recent years, cross-linking surgery is the only method to stop the progression of keratoconus and completely carried out in Tehran-Iran Noor Eye Hospital.

 Introduction to Corneal collagen cross-linking (UVX) as a treatment for keratoconus

In this surgery, creating more transverse ligaments in the corneal collagen tissue using riboflavin causes more corneal strength. The transverse ligaments in the cornea are like hooks and are responsible for preventing corneal bulge and irregularity.

 

Mechanism of thinning and weakening of the cornea

Young adults are susceptible to the accumulation of free oxygen radicals in their eyes. Under normal conditions, these free radicals are decomposed by the superoxide dismutase enzyme and do not harm the eyes. Some patients can not produce these protective enzymes. Eventually, the accumulation of these free radicals will damage the cornea tissue and reduce the strength of the cornea.

It takes about an hour and can be carried out in an ophthalmology operating room. During the surgery, after removing corneal epithelium ( the thin outermost layer of the cornea), a light sensitive eye drop, Riboflavin, is dropped into the cornea, which then is activated by UV light. It has been shown that this simple operation increases the transverse ligaments in the cornea collagen tissue, which ultimately increases the strength of the cornea.

The studies have shown that corneal cross-linking can slow down or stop the progression of Keratoconus. It is even observed that this surgery in some cases reverses the changes caused by keratoconus. It also observed that the combination of collagen cross-linking and implanting Intacs lenses ( intracorneal rings) has a synergistic effect on keratoconus and its effect is far greater than  INTACS implantation done separately. It is usually necessary to wear contact lenses after cross-linking, but it seems that the progression of corneal tissue destruction is inhibited by this surgery.

The studies conducted in Europe shown corneal cross-linking is generally an effective and safe method to arrest the progression of Keratoconus and in a few years that it has been carried out in the world and Iran-Tehran Noor Eye Hospital, it has not needed to be repeated.

In the first few days after surgery, blurred vision, tearing, burning and redness of the eye may occur. Redness, tearing and burning usually resolve after a few days, but blurred vision may take several weeks for your vision to stabilize completely. Usually, 1-3 days after the surgery, you can do your usual activities such as studying, driving, and other daily activities.

- When can UVX (cross- linking) surgery be used as a treatment for Keratoconus?

- How does UVX surgery cause to treat Keratoconus?

-  How long will UVX surgery last?

- Does UVX surgery need to be repeated?

- What are the common complications of UVX surgery?

- How long after UVX can the patients return to their daily activities?

 

 

- When can UVX (cross- linking) surgery be used as a treatment for Keratoconus?

UVX surgery is the only way to stop the progression of Keratoconus.

- How does UVX surgery cause to treat Keratoconus?

In this surgery, creating more transverse ligaments in the corneal collagen tissue using riboflavin causes more corneal strength.

- How long will UVX surgery last?

The duration of the surgery varies according to the patient's condition and treatment plan. However, the estimated time for this surgery is about an hour.

- Does UVX surgery need to be repeated?

The UVX surgery is effective and safe procedure and in a few years that it has been carried out in the world it has not needed to be repeated

- What are the common complications of UVX surgery?

In the first few days after surgery, blurred vision, tearing, burning and redness of the eye may occur. Redness, tearing and burning usually resolve after a few days, but blurred vision may take several weeks for your vision to stabilize completely.

 - How long after UVX can the patients return to their daily activities?

Usually, 1-3 days after the surgery, you can do your every day activities such as studying, driving, and other daily activities.