Astigmatism

What is Astigmatism?

Astigmatism is a relatively common and often minor eye condition that can cause fuzzy or unclear vision. The condition arises when the lens of an eye is not in a perfectly circular shape, but rather has a more rugby-ball shape.

There are two main types of astigmatism: regular and irregular. Regular astigmatism is more common, and occurs when the cornea curves more in one direction compared to the other. Irregular astigmatism occurs when the cornea is curved in several directions.

Astigmatism belongs to a set of eye impairments which are known as refractive errors. The other two well known related eye conditions are short-sightedness (medically known as myopia) and long-sightedness (known as hypermetropia).

What causes Astigmatism?

Regular astigmatism is usually present from birth, and though although it is unknown what the definitive cause is, there is a strong suggestion of a hereditary element. Irregular astigmatism is usually caused by a scar that develops on the cornea resulting from an eye injury or infection.

Other causes of astigmatism include cornea changes caused by eye surgery, keratoconus; an eye condition that causes the cornea to thin and change shape, keratoglobulus; an eye condition that causes the cornea to bulge, and any other condition that can affect the cornea.

What are the symptoms of Astigmatism?

Symptoms of astigmatism can vary person to person. Left unchecked, a patient can experience headaches and/or migraines, tiredness and eyestrain, especially after doing tasks that require long periods of focus, for instance using a computer or studying.

Short sightedness; where distant objects appear blurred but closer objects are visibly clear, or long sightedness, where the reverse is true, can often accompany astigmatism.

How is Astigmatism treated?

Many cases of astigmatism are very mild so treatment is often unneeded to correct your vision. If treatment is needed, it depends on the type of astigmatism. Regular astigmatism can be treated with corrective glasses or toric contact lenses, both which work by refocusing the incoming light that pass through the corrective lens, so that it is properly focused on to the retina.

Irregular astigmatism is can be treated through the use of laser eye surgery, which removes the outer layer of corneal surface cells, effectively changing the shape of the cornea, and leaving the cornea to heal.