Corneal collagen crosslinking is a surgical solution for corneal ectasias. These are a group of diseases that affect the cornea.
Corneal ectasias are rare diseases and include several variants, the most frequent of which is called keratoconus.
The cornea is a transparent tissue, a kind of watch glass that lies in front of the coloured part of the eye (iris), and is an integral part of the most superficial structures of the eye, being essential for vision.
In the absence of disease, the cornea, apart from being transparent, has a regular shape.
When corneal ectasia is present, the cornea becomes conically shaped, giving rise to high myopia together with what is called irregular astigmatism. This type of astigmatism results in a loss of vision that cannot be corrected with spectacles.
Corneal collagen crosslinking consists in the intertwining of the collagen fibres that compose the cornea (these fibres are normally linear and in this process they become a sort of "safety net", which gives more rigidity and resistance to the cornea). It is a process that occurs naturally with age, being more marked after the ages of 35 to 40.
Collagen crosslinking, used to treat corneal ectasia, consists of exposing the cornea to violet (UV) rays, which force this phenomenon to occur artificially. A vitamin, riboflavin (also called vitamin B2), is used to make the cornea more sensitive to UV rays while protecting the inner structures of the eye from any possible toxicity.
Collagen crosslinking not only increases the rigidity and resistance of the cornea, it also protects it from certain enzymes that are normally harmful, and these are the mechanisms by which it is able to slow down the evolution of the disease.
Several scientific studies show that this technique is capable of slowing down the evolution of the disease, thus avoiding the need to use rigid contact lenses or, above all, corneal transplantation, the only therapeutic alternative in the most advanced and severe cases.
Use of Femtosecond Laser in techniques complementary to Crosslinking
Collagen crosslinking may be combined with other techniques to treat corneal ectasia, such as laser, the implantation of intraocular lenses or small plastic segments (rings) inside the cornea in order to regularise its shape.
In the case of the use of intracorneal rings, these can nowadays be implanted using a specific laser, the so-called femtosecond laser. This latter method, the only one used in these cases in PCO, allows much greater predictability than manual techniques, alternative to the use of the laser, giving the surgeon better control over the depth at which the ring segments are placed and their respective location, which leads to better results and a faster visual recovery.
