Corneal cross-linking prevents keratoconus from progressing in 95% of cases

The number of diagnosed cases of keratoconus, a condition that affects the cornea, has increased due to new examination techniques.

During IMO’s Contact Lenses Conference, Dr Óscar Gris explained that keratoconus is a pathology that causes the cornea to become cone-shaped rather than round and results in irregular astigmatism, which, often, cannot be corrected with glasses or contact lenses. According to IMO specialist, “it is a fairly common disorder, and the number of diagnosed cases is increasing, because examination techniques are becoming more sensitive.”

Some patients are diagnosed by chance during examinations prior to myopia or astigmatism surgery, he added.

Occasionally, keratoconus remains in its early stages and does not develop, while more severe cases can result in the need for corneal transplantation. Advanced keratoconus mainly affects younger patients, for whom it is the leading reason for corneal transplantation. This is because, after the age of 40, the condition does not usually progress, as the cornea reverts to being naturally rigid through ageing. According to Dr José Luis Güell, “although keratoplasty (transplantation), especially deep anterior lamellar keratoplasty involving only the transplantation of the corneal layer affected by the disorder, has an excellent prognosis in severe cases, the objective is to prevent it by means of techniques that can improve the patient’s quality of vision, as well as preventing or delaying transplantation.”

 

The indicated treatment for keratoconus, when diagnosed in its early stages, is corneal cross-linking, which produces excellent results. A three-year follow-up study of 50 patients aged between 13 and 30, who had been treated for keratoconus at IMO with the cross-linking technique, has shown the effectiveness of the treatment in slowing the development of keratoconus. Unlike other treatments that do not slow down the condition, cross-linking prevents development in 95% of cases and improves the regularity of the cornea, resulting in better vision for 75% of patients.

The technique increases the rigidity of the keratoconus-weakened cornea through the administration of vitamin B2 (riboflavin) drops to the surface of the cornea, until they penetrate the interior. The cornea is subsequently exposed to a low ultraviolet light that causes a chemical reaction and increases the thickness of the collagen fibres and the links between them, thus improving the rigidity of the cornea.

During the conference, Dr Daniel Elíes stressed the important role of imaging techniques in the early detection of keratoconus and recommended that “patients with rare, oblique or increased astigmatism after the age of 18 should be referred to an ophthalmologist to perform a topography.” IMO specialist also made reference to intracorneal rings as an alternative treatment for more advanced stages of the disorder. The technique is indicated for healthy patients between the ages of 15 and 40, Down syndrome sufferers and people with atopic allergies, who habitually rub their eyes, which is completely discouraged by specialists. The rings shape the cornea and cause no rejection, and the patient can easily adapt to them (irritation only occurs during the first 24 to 48 hours).

The technique is also used to help contact lens specialists fit a lens to an irregular cornea before transplantation. Dr Elíes also noted that IMO is one of the most experienced centres for implanting these rings, a procedure that has benefited in the past two years from the introduction of the femtosecond laser to ophthalmic surgery. Doctors Daniel Elíes, Óscar Gris and José Luis Güell, IMO’s cornea specialists, highlighted the various threats to the anterior region of the eye at the Contact Lens Conference. The two problems that captured most attention were keratoconus and presbyopia (old eyes). In addition to other diseases that affect the cornea such as dry eye, blepharitis, conjunctivitis, pinguecula and pterygium (abnormal growth of the conjunctiva over the cornea) and limbal stem cell deficiency (corneal epithelial cell death).