As we previously reported before, astigmatism is one of defective eyes. It has two types which generously described as its cause.
The cornea is a clear (transparent) layer of tissue that covers the front of the eye. As well as transmitting and focusing light into the eye, it protects the eye from infection and damage. The cornea needs to have a perfect curve in order to bend (refract) light properly as it goes into the eye.
If the cornea does not curve perfectly – if one half is flatter or steeper than the other – the light that hits it will not refract properly and the retina at the back of the eye will receive an imperfect image. The person will have blurred vision from that eye, and then it called as astigmatism.
The problem is similar to corneal astigmatism, but exists in the lens rather than the cornea. The lens has variations in its curvature, rather than having a perfect curve, causing images to reach the back of the eye (retina) imperfectly. Most patients with lenticular astigmatism have a normally shaped cornea – the defect is only in the curvature of the lens.
Another reasons or causes, which related to corneal astigmatism:
# Having it since born
Experts are not sure why some people are born with a cornea that does not curve properly. Some studies indicate a baby has a higher risk of having astigmatism if one or both of the parents have it.
A higher percentage of babies born prematurely, as well as those born with a low bodyweight have astigmatism, compared to other babies.
Certain types of surgery or eye injuries that cause scarring of the cornea may cause astigmatism.
Keratoconus is one of a degenerative disorder of the eye where the cornea gradually thins and changes to a more conical shape, can also cause astigmatism.