Astigmatism is a common vision problem that can cause blurry vision, visual distortion, and difficulty seeing in low light. Although the exact cause is unknown, the condition develops when the shape of the cornea—the clear outer layer of the eye—becomes irregular. Some people may be more likely to develop astigmatism if they have a family history of the condition, have experienced eye trauma, or have undergone eye surgery.

An estimated 40% of people will have astigmatism at some point in their lives. Fortunately, there are several ways to manage or correct it, including wearing glasses, using specialized contact lenses, or undergoing surgical procedures to reshape the cornea.

Types of Astigmatism

Identifying the specific type of astigmatism can help your eye doctor recommend the best treatment. The main types include:

  • corneal: caused by irregularities in the curvature of the cornea

  • lenticular: due to changes in the shape of the lens inside the eye

  • myopic: occurs in people who are nearsighted

  • hyperopic: occurs in people who are farsighted

  • mixed: when one eye is nearsighted and the other is farsighted

Symptoms

Astigmatism can lead to several symptoms, most of which involve changes in how clearly you can see. These include:

  • blurry vision: affects both near and distant vision and can cause general visual distortion

  • squinting: narrowing your eyes in an attempt to see more clearly

  • eye strain: often from squinting, it can make your eyes feel tired, heavy, or watery, and may cause burning sensations or headaches

  • difficulty seeing in low light: especially noticeable at night or in dimly lit environments

Causes

In a healthy eye, light enters the eye and focuses precisely on the retina at the back of the eye. The retina sends signals to the optic nerve, which transmits visual information to the brain.

With astigmatism, an irregular eye shape causes the light to scatter instead of focusing evenly. As a result, the retina receives a distorted image, leading to blurred or fuzzy vision.

Although the cause of the irregular eye shape is still unclear, possible contributing factors include age-related vision changes and underlying eye conditions.

Risk Factors

Certain factors may increase your likelihood of developing astigmatism, including:

  • having a family history of the condition

  • experiencing an eye injury

  • undergoing eye surgery or having complications afterward

Diagnosis

If you notice symptoms like blurry vision or eye strain, an optometrist or ophthalmologist can perform a full eye exam. This typically involves:

  • visual acuity test: measures how clearly you can see at various distances

  • refraction: checks the degree of refractive error

  • retinoscopy: uses a special light to evaluate how light reflects from the retina

  • keratometry: measures the curvature of the cornea

  • pachymetry: evaluates corneal thickness to determine if surgery is appropriate

Treatment

Astigmatism treatment aims to correct the visual distortion and reduce symptoms. Some mild cases may not need treatment but should be monitored regularly. More severe cases often require vision correction using lenses or surgery.

Refractive Surgery

Surgical procedures reshape the cornea to help light focus properly on the retina. Common surgical options include:

  • astigmatic keratectomy: involves small incisions in the cornea to improve its curvature

  • LASIK (laser in-situ keratomileusis): removes tissue from the inner cornea using lasers

  • PRK (photorefractive keratectomy): similar to LASIK but reshapes both the outer and inner layers of the cornea

Orthokeratology

Orthokeratology, or ortho-k, is a non-surgical option involving rigid contact lenses worn overnight. These lenses gradually reshape the cornea while you sleep. Although results are temporary, wearing the lenses consistently helps maintain clearer vision.

Glasses and Contact Lenses

Many people manage astigmatism with prescription glasses containing cylindrical lenses, which improve clarity and reduce strain.

For those who prefer contacts, toric contact lenses are specially designed to fit the unique shape of astigmatic eyes. These lenses are not round like standard contacts and are marked to help ensure proper alignment on the eye.

proper care and hygiene are crucial when using contact lenses to avoid infection or irritation.

How to Prevent Astigmatism

Because the exact cause of astigmatism is unknown, there's no guaranteed way to prevent it. However, good eye care practices—like limiting screen time in preschool-aged children—may reduce the risk of vision issues later on.

While some cases of astigmatism may improve naturally over time, regular checkups are essential. following your eye doctor’s treatment plan can help prevent the condition from worsening.

Related Conditions

Astigmatism can increase the risk of developing other eye conditions, including:

  • vision loss: associated with nearsightedness and farsightedness

  • cataracts: clouding of the eye’s lens, often linked to aging

  • amblyopia (lazy eye): occurs when one eye becomes weaker than the other, especially in children

  • strabismus: also known as “crossed eyes,” where the eyes don’t align properly

Living With Astigmatism

Although there's no cure, astigmatism can be effectively managed. With the right glasses, contact lenses, or surgical options, most people live normal lives without significant visual limitations.

If left untreated, the condition can interfere with everyday tasks like reading, driving, or using screens. That’s why it’s important to schedule regular eye exams and follow any prescribed treatments.