Astigmatism Definition

Astigmatism is a common vision problem that occurs when the cornea, the clear front part of the eye, is not perfectly round. This can cause light to bend in different ways, making it difficult for the eye to focus images on the retina. Astigmatism can cause blurred vision at all distances, including near and far.

Types of astigmatism

There are three main types of astigmatism:

• Myopic astigmatism: This type of astigmatism occurs when the cornea is too curved, causing light to focus in front of the retina.
• Hyperopic astigmatism: This type of astigmatism occurs when the cornea is too flat, causing light to focus behind the retina.
• Mixed astigmatism: This type of astigmatism is a combination of myopic and hyperopic astigmatism.

Causes of astigmatism

The exact cause of astigmatism is unknown, but it is thought to be a combination of genetic and environmental factors. Astigmatism is often present at birth, but it can also develop later in life.

Risk factors for astigmatism

People who are at increased risk for astigmatism include:

• People with a family history of astigmatism or other eye conditions, such as keratoconus.
• People with thin corneas.
• People with severe myopia, which can cause blurred vision at distance.
• People with severe hyperopia, which can cause blurred vision at near.
• People with a history of certain types of eye surgery.

Symptoms of astigmatism

The symptoms of astigmatism can vary from person to person. Some people may not experience any symptoms at all. Common symptoms of astigmatism include:

• Blurred vision at all distances, including near and far.
• Difficulty seeing at night.
• Eye strain.
• Headaches.

Diagnosis of astigmatism

Astigmatism can be diagnosed by an eye doctor or optometrist during a comprehensive eye exam. The eye doctor will use a variety of tests to assess your vision, including:

• Visual acuity testing: This test measures how well you can see at different distances.
• Refraction testing: This test measures the strength of your glasses or contact lenses.
• Corneal topography: This test creates a map of the surface of your cornea.

Treatment for astigmatism

Most cases of astigmatism can be corrected with glasses or contact lenses. Glasses use lenses with different strengths to bend light correctly. Contact lenses can also be used to correct astigmatism.

In some cases, surgery may be an option for people with severe astigmatism. There are two main types of surgery for astigmatism:

• LASIK: This procedure uses a laser to reshape the cornea.
• PRK: This procedure uses a laser to remove a thin layer of tissue from the cornea.

Complications of astigmatism

If astigmatism is left untreated, it can lead to complications such as:

• Amblyopia, also known as lazy eye: This condition occurs when one eye does not develop properly due to lack of use.
• Eye strain and headaches.

When is astigmatism serious?

Astigmatism is not usually serious, but it can be a nuisance if it is not corrected. In rare cases, astigmatism can lead to more serious complications, such as amblyopia.

Can astigmatism be prevented?

Astigmatism cannot be prevented. Most people who have astigmatism are born with it.

How often should you get your eyes checked?

It is important to get your eyes checked regularly to detect astigmatism early. The frequency of eye exams depends on your age:

• Children: Children should be screened for vision problems every 1 to 2 years.
• Adults under age 40: Adults should get their eyes checked every 5 to 10 years.
• Adults ages 40 to 54: Adults should get their eyes checked every 2 to 4 years.
• Adults over age 55: Adults should get their eyes checked every 1 to 3 years.

If you wear glasses, you may need to get your eyes checked more often. People with diabetes should also get their eyes checked regularly.

Now, learn more about astigmatism and its treatment, and request a consultation with Dr. Osama Hakim, Consultant of Ophthalmology and Eye Surgery, and surgeries for squint, eyelids, and tear ducts at the Moroccan Eye Hospital in Dubai and founder and director of Medical Eye Center in Egypt.