Keratoconus
The Cornea is the front transparent part of the eye. As the transparent tissue that it is we can see clearly through it. It has the greatest refractive power of all the media of the eye. It is a gradual, slowly progressive disease, it may get worse over a number of years and stops around 40 years of life and occurs in about 1 in 2000 people. It is characterized by a gradual thinning of the cornea, as a result of which it deforms forward and takes the shape of a cone.
As a result of this deformity, astigmatism mainly develops and myopia develops and vision is greatly reduced. This condition typically begins during adolescence or shortly thereafter and has an evolutionary course that differs between the two eyes and from patient to patient. Initial treatment is with glasses that correct astigmatism and myopia or hard contact lenses.
Cause
The causes of keratoconus are not known. It is generally considered a hereditary disease and many factors are blamed for its occurrence, allergies to rubbing the eyes and mainly abnormalities of the dosage of the different parts of the cornea.
Symptoms and Features
- In the early stages of the disease, it causes slightly blurred vision
- Sensitivity to bright light
- Difficulty driving at night
- Abnormalities, astigmatism not corrected by glasses
- Monocular diplopia
- Eye pain
- Eye irritation, eye rubbing
Diagnosis
Diagnosis & Diagnostic tests
The diagnosis is usually made through an ophthalmological examination carried out by a specialist ophthalmologist. The clinical symptoms are often enough to suspect the existence of keratoconus:
• Shadowscopy: shows scissor reflection abnormalities.
• Direct ophthalmoscopy: shows a reflex, (Redreflex).
Keratometry high: (Ks mild 48 D, < moderate 48-54 D, severe keratoconus > 54 D)
The diagnosis, however, is easily verified today by analyzing the curvature of the anterior surface of the cornea with computed topography that demonstrates the abnormality on the surface of the eye. Newer topography systems can simultaneously check the curvature of the posterior surface of the cornea, whose abnormalities appear to precede the anterior surface. At the same time, with the same examination, we can check with great precision the thickness of the cornea at every point. The thickness of the cornea is a quantity of fundamental importance for our therapeutic intervention.
Repeating the examination at regular intervals is necessary to objectively check the stability or deterioration of the condition. This test should usually be repeated every 4-12 months depending on the age of the patient.
Treatment
Treatment of keratoconus. In its initial stages, keratoconus is essentially mild astigmatism, it can be treated in similar ways, such as:
Contact lenses (RGP or GP) or eyeglasses can be used to correct the mild myopia and astigmatism caused by keratoconus in the primary stage, however to some extent a rigid air permeable (RGP) contact lens will correct keratoconic vision better.
Rigid air permeable contact lenses (RGP or GP) can correct vision as keratoconus progresses. The lens’s rigid material allows it to apply pressure to the cornea, replacing the irregular shape of the cornea with a smooth, uniform refractive surface to improve vision
- Corneal crosslinking (CXL) or collagen cross-linking method is one of the most effective methods for the treatment of keratoconus. With this method we try to intervene in the collagen of the cornea with the use of vitamin ribiflavin B2 but also with the appropriate use of light of a specific wavelength, UV-A, in order to affect the elastic owners of the cornea, so that it ceases to be loose as it is in the case where he suffers from keratoconus, to harden.
- Intracorneal rings. The treatment of keratoconus with the new kerarings intracorneal rings is completely successful, in a percentage that exceeds 95%. Their implantation, in combination with collagen crosslinking therapy, significantly reduces the percentage of patients with keratoconus. Kerarings intracorneal rings are biotechnological product and implanted into the corneal layer, they normalize the anterior surface of the cornea and reduce the refractive error due to keratoconus and other corneal stretching disorders “Unlike other corneal implants, kerarings are specifically designed to treat keratosis pilaris, giving better smoothing of the corneal surface”. In addition, the goal of intracorneal rings is to correct abnormal astigmatism. Residual refractive errors after Keraring insertion can usually be corrected with corrective glasses or contact lenses.
- Corneal transplant surgery is necessary in very advanced stage keratoconus due to scarring, extensive thinning or contact lens intolerance. Corneal transplantation is our last option in the treatment of keratoconus. These transplants have a particularly successful 92-95% for people aged 20-35. Replacing the central part of the cornea with a graft from a healthy donor is called keratoplasty or corneal transplantation. Depending on whether the entire central part is transplanted or only the diseased layer of the cornea, the operation is called penetrating or partial thickness keratoplasty.