What is keratoconus? Dr. Nir Erdinest
The definition of keratoconus is in the name of the disease. Keratoconus means Kerato (cornea) and Conus (coned cornea). This is an eye disease characterized by corneal tightening, weakening corneal tissue and corneal protrusion, into the shape of a cone (irregular curve) instead of a dome shape. Keratoconus is considered a mild to moderate eye disease.
The disease is wide-ranged and in its early stages, there are patients who may be unaware of it for years. The incidence ratio of keratoconus in the population is 1:2000, with 10-15% of the cases having a genetic background. The process of the disease is caused by complex changes and the weakening of certain layers in the cornea. The changes create an asymmetry in the corneal curve (with the lower part being convexed from the top) and the increasing optical strength in the center of the cornea. These changes cause irregular astigmatism (cylinder), which creates visual distortion.
- Keratoconus usually develops during adolescence and is mainly characterized by blurring of vision and inadequate visual acuity, such as halos.
- In keratoconus disease there is an abnormal increase in the intensity of astigmatism (cylinder) on a faster rate than usual.
- A distinct characteristic of keratoconus is the dissatisfaction with glasses. Glasses have limited correction ability for keratoconus compared to contact lenses.
In the past, before the use of corneal topography devices, the diagnosis was only made with the appearance of significant symptoms and visible changes in the cornea.
The diagnosis was made using a ray of light in a retinoscope, or examination of the structure of the cornea in a crack lamp, when scarring or corneal edema occurs.
Today, with the availability of advanced mapping devices it is possible to diagnose keratoconus in its early stages. An advanced rear cornea mapping device is used to detect the tightening of the rear cornea.
Therefore, it’s possible to treat keratoconus in its early stages and even prevent its development using crosslinking.
The diagnosis also includes the classification of the keratoconus, and the eye doctor determines whether the disease is subclinical (isn’t felt and has no symptoms), or clinical.
The classification is determined by the results of the corneal topography and the cornea diagnosis itself.