What Is Astigmatism?

Astigmatism is a frequent refractive defect in the eyes that produces blurry vision. It happens when the cornea (the transparent front surface of the eye) or the lens inside the eye are irregularly shaped, causing light to be improperly focused on the retina. In a normal eye, the cornea and lens have a smooth curvature, allowing light to be precisely focused on the retina, resulting in clear vision. However, with astigmatism, the cornea or lens is bent more in one direction than the other, like the shape of a football rather than a basketball.

What are the causes?

Irregularly shaped cornea: Astigmatism is mostly caused by an unevenly shaped cornea. The cornea may be oval or football-shaped, rather than spherical like a basketball. This imperfection causes light to concentrate unevenly on the retina, resulting in impaired vision.

Irregularly formed lens: In certain circumstances, astigmatism is caused by an irregularly shaped lens within the eye rather than the cornea. This is referred to as lenticular astigmatism.

Genetics: Astigmatism can be genetic, which means it can run in families. If one or both parents have astigmatism, their offspring are more likely to develop it.

Eye injuries or operations: Trauma to the eye or certain eye procedures can change the shape of the cornea or lens, causing astigmatism.

Keratoconus: Keratoconus is a condition where the cornea gradually thins and bulges into a cone shape, resulting in astigmatism along with other vision problems.

Certain medical conditions: Some medical conditions, such as Down syndrome and Ehlers-Danlos syndrome, are associated with an increased risk of astigmatism.

Childhood development: Astigmatism can develop or change during childhood as the eyes grow and develop.