What is it?
It is a degenerative disease of the cornea (transparent part of the anterior segment of the eye) in which the cornea loses its natural rounded shape and adopts a conical shape.
Keratoconus usually has a bilateral presentation (affects both eyes), but asymmetric (affects one eye first). The onset of keratoconus usually occurs around puberty, progressing in the following 10-20 years until a gradual stabilization occurs, around 35-40 years of age.
Causes
Its cause is not exactly known, although it appears to have a certain genetic predisposition. On the other hand, there seems to be a certain relationship between eye scratching (either due to allergy, compulsion, or syndromes associated with psychomotor retardation) and keratoconus.
Can keratoconus be prevented?
It is very important that any patient diagnosed with keratoconus avoid scratching the eyes, as it accelerates its progression and worsens its prognosis.
Symptoms
The main symptom produced by keratoconus is a vision reduction, mainly related to important changes in graduation (increased myopia and the appearance of irregular astigmatism). Keratoconus can produce various symptoms, among which are: blurred vision (more accentuated as the disease progresses), a certain degree of visual distortion, increased sensitivity to light (photophobia), and eye redness. In very advanced cases, corneal edema (opacification of the cornea that causes significant loss of vision) may appear.
As keratoconus worsens, visual disturbances cannot be corrected with glasses, and some intolerance to contact lenses often occurs.
Diagnosis
The diagnosis of keratoconus can be made by a complete standard ophthalmologic examination, with special attention to visual acuity, refractive errors, and the anterior segment of the eye. In the most incipient forms, it may be necessary to carry out a corneal topography (topographic study of the cornea) and a keratometry to measure the curvature of the cornea and know the corneal surface with precision. The detection of keratoconus early in the process is essential to obtain good clinical results.
Treatment
The most incipient and / or mild cases can achieve good vision with glasses or contact lenses. Moderate cases require contact lenses to have acceptable vision.
In some cases, it may also be necessary to resort to surgical treatments such as corneal cross-linking, intrastromal rings, or keratoplasty (corneal transplantation).
Corneal cross-linking is the only effective treatment to slow the progression of keratoconus. It is a minimally invasive surgical procedure with which, in combination with the administration of vitamin B2 (riboflavin) and a low dose of ultraviolet light, it is possible to increase the stiffness of the cornea. In most cases it is able to stop the progression of the disease. Corneal cross-linking provides greater clinical benefit in incipient cases, so early diagnosis is very important.
Intrastromal or intracorneal rings are implants made of biocompatible material that are inserted into the central layers of the cornea (stroma), using a femtosecond laser, which achieves greater precision and safety when placing the implant. Intrastromal rings flatten the cornea and regularize its surface, improving vision.
In some cases it may be necessary to perform a cornea transplant (the cornea with keratoconus is removed and replaced with a healthy one). At present, a selective transplant can be performed, in which only the layers of the cornea that are affected are replaced and the healthy tissue of the patient is maintained. Corneal transplantation, either full-thickness (penetrating keratoplasty) or partial-thickness (deep lamellar keratoplasty), is reserved only for the most advanced cases.
