Keratoconus: Cross Linking. When, Why and How?

Keratoconus can be treated through Cross Linking , the practice of which aims to make the cornea more resistant. This intervention is therefore an intervention that strengthens the cornea, resulting in the formation of more numerous bonds between the collagen fibers that constitute it. A bit as if, wanting to strengthen a house, the pillars were tied together to make the structure of the house more resistant. However, let’s start from the definition of keratoconus : it is a very widespread disease in which the cornea thins and deforms over time, leading to a progressive loss of vision. Keratoconus is due to a genetic fragility of the collagen molecules that make up the cornea and to repeated traumas that deform a cornea that is already more fragile from the start. Thanks to progress in research, this disease can now be treated with various non-invasive interventions .

Rubbing your eyes exacerbates keratoconus: conservative treatment

A keratoconus treatment strategy, which in many cases avoids the need for any intervention, is to reduce repeated trauma to the cornea. This consists of example in stopping the bad habit of rubbing your eyes. Often those who suffer from keratoconus also suffer from allergic conjunctivitis with itching and various discomforts which lead to finding relief by rubbing the eyes. This gesture unfortunately leads to a worsening of keratoconus and vision. Simply by interrupting this habit, an improvement in corneal topography is often observed. Another habit to avoid in these predisposed subjects is that to sleep on your stomach with your face towards the pillow; this position is often associated with repeated trauma of the eye against the pillow which can lead to worsening of vision. Dr. Badalà , expert in Micro Surgery of Keratoconus, interviewed on the subject by the Journal of Cataract and Refractive Surgery , confirms how it is advisable to modify incorrect lifestyle habits before undergoing surgery for the treatment of keratoconus, putting into practice a real conservative treatment: “It can often be enough to modify incorrect lifestyle habits to witness an arrest in the progression of keratoconus or even an improvement in the disease and vision”

Cross Linking Keratoconus: When and Why?

When conservative treatment alone is not sufficient to guarantee a good result, and only then, does it make sense to undergo surgery. As anticipated, today there are several minimally invasive interventions for keratoconus. Cross linking is one of these interventions, however today it is often suggested as the solution for all patients with keratoconus. This is not the case unfortunately. When Keratoconus is advanced and vision is impaired, Cross Linking is no longer useful. The ideal candidates for Cross Linking are therefore to be found among those who have keratoconus in the initial phase and who have not managed to avoid its progression, despite having implemented conservative treatments which have led to a change in their lifestyle habits .

Cross Linking Keratoconus: How?

Cross Linking for Keratoconus is now performed with different strategies , however not all have demonstrated equal effectiveness in controlled clinical studies. The Transepithelial Cross Linking technique for example appears to be less effective than the Epi-Off Cross Linking technique . In the first technique, the cornea is left intact and the treatment is performed. In the second, the corneal epithelium (the superficial layer of the cornea) is removed and only then is Cross Linking performed. The difference is that with Epi-Off Cross Linking the part of the cornea that is cross linked, i.e. strengthened, is greater and therefore the treatment is more effective. Cross linking takes place in two phases: a first phase in which a molecule, which is usually riboflavin, is made to penetrate inside the cornea and a second phase in which the cornea is irradiated with an ultraviolet light source. In the cornea soaked in riboflavin, ultraviolet light causes the formation of bonds between the collagen fibers, making the cornea more resistant. Depending on the riboflavin, the light source and the exposure times, there are also very important differences in the type of Cross Linking that is performed. The result of this treatment is observed after a few months; usually the most important effect is observed between one and two years after the Cross Linking intervention. “It is good practice to rely on centers specialized in the treatment of keratoconus. Centers that know how to offer all the treatment alternatives currently available to be able to choose the best strategy together with your trusted specialist” concludes Dr. Badalà in his interview. To read the full Journal of Cataract and Refractive Surgery article click here .