A clinical condition characterised by thinning and forward protrusion of the cornea resulting in conical shape. This disorder is usually bilateral, with onset at the age of 10 -14 years. Affects both sexes, with a slight female preponderance. Although it has been reported in families, the risk of inheritance is reasonably low.
Why does it occur ?
Etiology of this condition is still not clear. . Eye rubbing, hormonal variations , genetic predisposition have been proposed to be causative factors in the disease. It is possible that this condition could be secondary to increased breakdown of the stromal collagen lamellae by the lysosomal enzymes released by the basal epithelium in these eyes.
The substance of the cornea consists of hundreds of layers that are linked to each other by a substance called as collagen. if these collagen cross links between the layers are lost due to keratoconus, there is a progressive corneal thinning and stretching which progresses often in both eyes. The cornea bulges forwards into a irregular cone shape causing distortion of image.
The eye develops astigmatism and myopia and vision becomes severely blurred.