DEFINITION AND PATHOLOGIES: KERATOCONUS AND PROGRESSIVE, NON-INFLAMMATORY CORNEAL DYSTROPHY
Keratoconus is a degenerative disease of the cornea that involves the deformation of the optical corneal surface (generally an irregular myopic astigmatism) that is associated with the reduction of the thickness of the cornea and progressive reduction of visual capacity. Keratoconus usually arises during adolescence (between 14 and 20 years of age). Typically, it appears in an asymmetric way and it affects one eye and after some years, the other. Unilateral forms are very rare and this is marked as a progressive disease.
Visual disturbances of a patient with keratoconus depend on the irregular form of the corneal surface. Therefore, it is essential to study its characteristics to define the development of the disease and monitor its progression. Corneal tomography is carried out with Pentacam at the Blue Eye Ocular Microsurgery Centre, which reconstructs, in 3D, the anterior segment of the eye and gives an evaluation of the characteristics of the cornea, anterior chamber, and crystalline lens. It is undoubtedly the most modern and sophisticated diagnostic tool available today. This examination is non-invasive and presents no risks. In the study of keratoconus, corneal tomography is associated with another non-invasive examination, endothelial microscopy, which gives the number and morphological characteristics of endothelial cells.
How Is Keratoconus Treated
Today, there is a definitive cure for keratoconus, however, in its early stages, the visual defect generated by the disease can be corrected with glasses or soft contact lenses, rigid, and, in more advanced cases, custom-built.
In cases where the central portions of the cornea are transparent, it always pays to have recourse to conservative techniques. Among these, the most recent therapy for the treatment of keratoconus is the cross-linking procedure that serves to reinforce the collagen fibers through the instillation of vitamin B2 (riboflavin) and the subsequent irradiation of the ocular surface with a laser ultraviolet ray that activates the medication. The treatment is performed under topical anesthesia (eye drops) that lasts about 40 minutes.
- Intrastromal Rings
In cases of keratoconus at later stages, intrastromal segments can be introduced. These rings are invisible to the naked eye and have the purpose of restoring physiological form thereby reducing maximum deformation and irregularity of the central portions of the cornea. Usually, the surgery allows for an improvement of both the naked eye vision and of that with glasses or contact lenses.
Finally, only in the most serious cases and when none of the techniques described above has proven effective, the recourse must be partial or total transplantation of the corneal flap.