Keratoconus is a bilateral corneal ectasia that causes progressive non-inflammatory corneal thinning. The beginning is usually in adolescence and can progress to adulthood.
Map of curvature of a normal eye
Map of curvature of an eye with keratoconus
It is not known very well what is its origin. There are theories of genetic origin, immune, endocrinological, ... What is common is a history of asthma, allergies, atopias, chronic rubbing of the eyes.
The symptomatology is blurred vision, glare, light photofobia and occasionally double vision. It can cause significant visual distortion due to irregular astigmatism and myopia and secondarily to corneal scars.
At the start you can wear glasses or soft contact lenses, but as the vision quality progresses, it decreases and then semi-rigid contact lenses (normal, semi-scleral or scleral) must be adjusted. Currently, the technique of cross-linking can slow down its progression (riboflavin drops are administered and UV-rays are applied to strengthen the bonds of collagen molecules and thus strengthen the cornea). Also, there is the technique of Intacs (small segments of a plastic material that are placed in the cornea, changing its curvature from irregular to symmetrical and uniform, achieving a better image). The last option is surgery (lamellar or penetrating keratoplasty).