Description
Astigmatism is a disease of the Eye.
A defect in the Eye due to which the light fails to meet at the Retina is Astigmatism.
It is an imperfection of the Cornea or the Lens. The Cornea is not spherical and the Eye is not completely round in shape.
The Cornea and the Lens focus the images.
Cornea : It is a dome shaped transparent structure forming the outer surface of the Eyeball. It covers the front portion of the Eye. It protects the Eye from the harmful substances like Germs and dust mites.
Lens : It is a clear and biconvex structure present behind the Iris and the Pupil. It refocuses the light on to the Retina that is refracted by the Cornea.
When the light strikes the Cornea, it refracts the light into the Lens. The Lens focus this light on to the Retina. The Retina makes an image in the Brain.
If either the Cornea or the Lens is irregular, they do not refract the Light properly. This results in Astigmatism.
At night a spot of light looks like a streak. If there is no other defect in the Eye, the streak will be vertical. But, if in addition to Astigmatism, the Eyeball is cylindrical rather than spherical, then the angle of the streak depends on the angle of the cylinder.
Causes of Astigmatism
Myopia or Hyperopia
Irregular shape of the Cornea
Irregular shape of the Lens
If not treated properly, Astigmatism may cause
Blindness. Vision decreases very slowly.