Astigmatism is a condition that causes your vision to become blurred. Like near- or far-sightedness, it is caused by an irregular shape of the eyeball and can usually be treated with glasses or toric contact lenses. Here, we explore the causes, symptoms and treatment options available for astigmatism.
What is astigmatism?
Astigmatism is caused when the shape of your lens or your cornea, the transparent part at the front of your eye, is not the shape that it should be. The cornea is responsible for refracting light that enters the eye and focusing it so that we see clearly. When there is an abnormal curve in its shape, and the eye is more rugby ball shaped, this changes the way that light enters the eye, and onto your retina. As a result, the light is focused on more than one place and your vision becomes blurred. It is a type of refractive disorder.
Are there different types of astigmatism?
Astigmatism can affect two different parts of the eye. If the cornea is an irregular shape, it is referred to as a corneal astigmatism. When the lens is misshapen, it is referred to as a lenticular astigmatism.
What causes astigmatism?
Usually, astigmatism is something that you are born with. The exact cause isn’t known but it is believed to be genetic. It is much more likely to occur in people who have far- or near-sightedness.
Sometimes, astigmatism can develop after an injury has occurred in the eye, or following an eye disease. It can also be caused by some types of eye surgery, like the removal of cataracts.
Symptoms of astigmatism
Symptoms can be different for everyone and some people may have no symptoms at all. Usually, astigmatism causes blurred or fuzzy vision. It can also cause headaches, squinting, and difficulty seeing at night, eye irritation and eyestrain. When astigmatism occurs in children, it can cause something known as a lazy eye.
If you suffer from any of these symptoms, book an appointment to see your eye doctor.
Diagnosing astigmatism
Astigmatism is diagnosed during an eye examination by an optometrist or ophthalmologist using non-invasive methods. Sometimes it can be diagnosed through a test which assesses how good your vision is, known as a visual acuity assessment. A refraction test may also be used to assess your vision while you look through a number of different strength lenses. Your eye doctor can then use something called keratometry, which allows them to measure the curvature of your cornea.
Treatment for astigmatism
Once astigmatism has been diagnosed, your doctor will advise you on the best treatment option. Often, if the astigmatism is mild, then it won’t require any treatment. If it is affecting your vision, or causing any other side effects, then they may prescribe glasses or toric contact lenses.