Special contacts called toric lenses are required for those with moderate to severe astigmatism.

What Is Astigmatism?

Astigmatism is a refractive error of the eye.  The refractive error that occurs in those with astigmatism is caused by an irregularly shaped cornea or lens.

Under normal conditions, light enters the eye through the cornea and the lens and is projected onto the retina, which sends the impulses through the optic nerve to the visual cortex of the brain.  In the case of a refractive error, the light does not bend correctly causing distorted and/or blurred vision.

Different Contact Lens Designs

There are several contact designs available depending on personal taste and medical necessity. Spherical contacts are the typical lenses used to correct near and farsightedness. Bifocal contacts allow you to see both near and far by either providing two powers in one lens, or one power in each. Orthokeratology lenses are used to reshape your cornea while you sleep so you can see clearly during the day.  Finally, toric lenses are used to correct both vision and astigmatism.

How Toric Lenses Work

Regular soft contact lenses conform to the shape of the eye. Because astigmatism is caused by an irregular shaped cornea or lens, these contacts are ineffective at helping to refract the light correctly.

Unlike regular contact lenses that have one corrective power, toric lenses combine two, one for the vision correction the other for astigmatism.

Toric lenses are specially designed to stay in place with weighted areas around the lens to compensate for the corneal irregularity to minimize rotation and shifting.