What Is Astigmatism?

At a Glance: Astigmatism

• What it is: A common refractive error where the cornea or lens is shaped more like a football than a basketball, so light scatters across the retina and vision is blurry at all distances.
• Who gets it: About 1 in 3 American adults. It often runs in families and is frequently present from birth.
• Key symptoms: Blurry vision near and far, eye strain, headaches, squinting, and glare or starbursts around lights at night.
• How it's fixed: Eyeglasses, toric contact lenses, or refractive surgery (LASIK, PRK, or lens implants). Most regular cases can be corrected so vision is clear or significantly improved.
• When to see a doctor: New or worsening blurry vision, headaches with eye strain, or a child squinting or struggling to read the board at school.

What Is Astigmatism?

Astigmatism is a common, treatable eye condition that happens when the cornea or lens has an irregular shape. It is a type of refractive error that causes blurred vision at all distances.

A normal cornea curves smoothly, like the surface of a basketball. An astigmatic cornea curves more like a football: steeper in one direction than the other. That uneven curve sends light to two or more focal points instead of one, and your brain reads the result as blurry or distorted.

You can have astigmatism in one or both eyes. It is often present at birth and frequently shows up alongside other refractive errors:

• Myopia (nearsightedness). Known as myopic astigmatism.
• Hyperopia (farsightedness). Known as hyperopic astigmatism.

Mixed astigmatism is a little different: one part of the eye's curve focuses light in front of the retina and another part focuses it behind, so vision is blurry or distorted at any distance.

How Does Astigmatism Affect Your Vision?

Astigmatism scatters light across your retina instead of focusing it on a single point. With a smoothly curved cornea, light from one object converges on one spot at the back of the eye. With astigmatism, the irregular curve sends light to two or more focal points, and the image you perceive is blurred or doubled.

Types of Astigmatism

Astigmatism is classified two ways: by which part of the eye is affected, and by how regular the curve is.

By Affected Structure: Corneal vs. Lenticular

• Corneal astigmatism. The front surface of the eye (the cornea) has an uneven, football-shaped curve. This is the more common type.
• Lenticular astigmatism. The lens inside the eye is misshapen. The cornea may look normal.

It is possible to have both types in the same eye.

By Curve Regularity: Regular vs. Irregular

• Regular astigmatism. The cornea or lens is steeper along one even axis, like a football lying on its side. Most astigmatism is regular and corrects well with glasses or contacts.
• Irregular astigmatism. The curve is uneven in more than one direction, often from an eye injury, corneal scarring, or a condition like keratoconus. Irregular astigmatism is less common and harder to correct with standard glasses.

What Causes Astigmatism?

Astigmatism is usually present at birth and tends to run in families. It can also develop after eye injury, eye surgery, or certain eye diseases like keratoconus. Researchers do not know exactly why the cornea or lens grows in an irregular shape.

What does not cause astigmatism: squinting, reading in dim light, watching television up close, or spending long hours on screens. These habits can leave your eyes tired, but they do not change the shape of your cornea.

Who's at Higher Risk

Family history is one of the most consistent risk factors: having a parent with astigmatism raises your odds. Other risk factors include:

• Older age (the cornea and lens shift with age)
• Eye injuries that scar or thin the cornea
• Eye surgery, including cataract surgery and LASIK
• Keratoconus and other corneal diseases
• Having another refractive error like myopia or hyperopia
• Maternal smoking during pregnancy: Some pediatric studies find an association; others do not

Astigmatism is one of the most common refractive errors in the U.S. Older national survey data (NHANES 1999-2004) estimated that about 36% of American adults had astigmatism, and current consumer-facing estimates from the AOA and AAO put the figure at roughly 1 in 3.

Symptoms of Astigmatism

Most people with astigmatism have blurry vision at both near and far distances. Mild astigmatism with no other vision problems may cause no noticeable symptoms at all.

Common symptoms include:

• Blurry or distorted vision at any distance
• Squinting or straining to see clearly
• Glare, halos, or starbursts around lights at night
• Headaches, especially after reading or screen time
• Eye strain and fatigue
• Trouble seeing in low light

Symptoms often appear gradually. Many people only notice them once they compare their vision with corrected vision after an eye exam.

Astigmatism in Children

Astigmatism is common in children and is one of the refractive errors that pediatric vision screenings are designed to catch. Children often will not report blurry vision because they do not know their sight is different from anyone else's.

Watch for these signs at home and at school:

• Squinting or tilting the head to see
• Sitting close to the TV or holding books close to the face
• Frequent headaches or eye rubbing
• Trouble reading the board at school, or a sudden drop in school performance

Why early detection matters: Uncorrected astigmatism in early childhood can contribute to amblyopia (lazy eye). When one eye sends a consistently blurred image, the brain learns to favor the other eye, and vision in the weaker eye never fully develops. Treating astigmatism early helps prevent this.

The American Association for Pediatric Ophthalmology and Strabismus (AAPOS) recommends age-appropriate vision screening starting in early childhood, with repeat screening every one to two years after age 5. Talk to your pediatrician, family physician, or eye doctor if you suspect a vision problem, and follow through on the pediatric vision screenings offered at well-child visits.

How Is Astigmatism Diagnosed?

A comprehensive eye exam is the only way to confirm astigmatism. Your eye doctor combines several quick tests to measure how your eye focuses light and how the cornea is shaped.

The exam usually includes:

• Visual acuity test. You read letters from a chart at set distances to measure the sharpness of your vision.
• Refraction test. Your doctor uses a phoropter (the instrument with rotating lenses) to find the lens prescription that gives you the clearest vision. This is where the CYL value on your prescription comes from.
• Keratometry or corneal topography. Both measure the curve of your cornea. Topography produces a detailed map of the surface and is useful when irregular astigmatism is suspected.
• Autorefraction. An instrument shines light into the eye and measures how it reflects back, giving the doctor a starting prescription.

A slit-lamp exam (a close look at the eye through a lighted microscope) is often included to check overall eye health, but it is not how astigmatism itself is measured.

How Is Astigmatism Measured?

Astigmatism is measured in diopters (D), the same unit used for nearsightedness and farsightedness. Higher diopter values mean more correction is needed. Many eye doctors begin to consider glasses or contacts around 1.5 D, though the right threshold depends on symptoms and lifestyle.

A commonly used severity scale looks like this (these are general ranges, not a universal standard):

• Mild. 0.10 to 1.00 D
• Moderate. 1.00 to 2.00 D
• Severe. 2.00 to 4.00 D
• Extreme. over 4.00 D

For a deeper breakdown by diopter level, see our guide to astigmatism severity.

How to Read Your Astigmatism Prescription

Your astigmatism prescription has three numbers: sphere (SPH), cylinder (CYL), and axis.

• SPH is the lens power for nearsightedness or farsightedness, in diopters.
• CYL is the strength of the astigmatism correction, in diopters. A value of -1.00 means 1.00 diopter of astigmatism correction.
• Axis is a number from 1 to 180 that tells the lens-maker how to orient the cylinder correction on the lens.

If you see numbers in all three columns, you have astigmatism on top of any nearsightedness or farsightedness.

Can You Fix Astigmatism?

Yes. Regular astigmatism is treated effectively with corrective lenses or refractive surgery. Your eye doctor measures the irregular curve and prescribes the option that fits your prescription and lifestyle.

Irregular astigmatism is harder to correct. Standard glasses may not fully sharpen the image, and treatment often shifts to specialty rigid or scleral contact lenses or, depending on the cause, a corneal procedure.

Astigmatism Treatment Options

Astigmatism treatment falls into three buckets: corrective lenses (glasses, toric contacts, specialty rigid or scleral lenses, or Ortho-K), corneal refractive surgery (LASIK, PRK, or LASEK), and lens-based procedures (toric IOLs during cataract surgery, refractive lens exchange, or phakic IOLs). Most cases are handled with the simplest option: eyeglasses.

Eyeglasses

Glasses are the simplest and most affordable way to correct astigmatism. A cylindrical lens, set at the correct axis, redirects light to a single focal point on the retina.

Eyeglasses correct astigmatism across the full diopter range, from mild (under 1.00 D) through extreme (over 4.00 D). Your eye doctor will weigh whether glasses, contacts, or surgery fits your prescription and daily life best.

If your astigmatism comes with another refractive error like presbyopia, your doctor may recommend progressive lenses that combine both corrections in a single pair.

Contact Lenses

Toric contact lenses are contacts designed for astigmatism: they include cylinder correction plus stabilization features that keep the lens lined up on the eye. Soft toric lenses correct mild to moderate astigmatism, generally up to about -2.75 D. Rigid gas-permeable (RGP) lenses correct higher diopters and irregular astigmatism that soft lenses cannot.

Your doctor may prescribe:

• Soft toric lenses for everyday wear
• Rigid gas-permeable (RGP) lenses for higher prescriptions or irregular corneas
• Scleral lenses that vault over the cornea, useful for keratoconus or post-surgical irregular astigmatism

To compare brands, see our review of the Best Contacts for Astigmatism.

Laser Eye Surgery

Laser refractive surgery permanently reshapes the cornea to reduce or correct astigmatism, though vision can shift over time and some people still need glasses, contacts, or an enhancement procedure later on. The three most common procedures are:

• LASIK (laser-assisted in situ keratomileusis). LASIK treats astigmatism and other refractive errors. The surgeon creates a thin corneal flap, reshapes the tissue underneath with a laser, and replaces the flap. Not everyone is a candidate for LASIK.
• PRK (photorefractive keratectomy). PRK reshapes the cornea with a laser but does not create a flap. That makes it a better fit for people with thin corneas or active lifestyles where a flap could be displaced.
• LASEK (laser-assisted subepithelial keratectomy). LASEK sits between LASIK and PRK: the surgeon lifts and replaces the epithelial layer rather than cutting a full corneal flap.

Orthokeratology (Ortho-K)

Orthokeratology uses specially fitted rigid contact lenses, usually worn overnight, to temporarily reshape the cornea. Vision may improve within days to weeks, but the effect is temporary; maintenance lens wear is needed to keep the correction in place.

Ortho-K is used for mild to moderate astigmatism and is also prescribed for myopia control in children.

Lens Replacement Surgery

Lens replacement surgery (refractive lens exchange) removes the eye's natural lens and replaces it with a clear intraocular lens (IOL). When the patient has astigmatism, a toric IOL can correct it during the same procedure.

This option is most commonly used during cataract surgery to treat pre-existing corneal astigmatism, rather than as a standalone elective procedure.

Phakic Intraocular Lenses (IOLs)

Phakic IOLs are implanted in front of or behind the iris without removing the eye's natural lens. They are FDA-approved for moderate to severe myopia, and some lens options may also correct astigmatism in selected candidates.

Can Astigmatism Be Prevented or Get Worse?

There is no proven way to prevent astigmatism. It is not caused by squinting, reading in dim light, screen use, or any everyday habit. Most cases are present from birth.

Astigmatism can shift over time, though. The cornea and lens both change with age, and an eye injury or eye surgery can change the curve as well. Regular eye exams catch these shifts so your prescription stays current.

What to Expect: Astigmatism Prognosis

Astigmatism is a lifelong condition for most people, but it does not cause permanent vision loss when it is corrected. Glasses, contacts, or surgery restore clear vision for the great majority of regular cases, and most people with astigmatism live with no daily limits once they have the right correction.

The prescription may drift a little over time. A routine eye exam every one to two years is enough to keep up with changes.

When to See an Eye Doctor

See an eye doctor for a comprehensive eye exam if you have:

• New or worsening blurry vision at any distance, especially if it makes reading or driving harder
• Frequent headaches with eye strain or after long stretches of screen time
• Glare, halos, or starbursts around lights at night that are new or getting worse
• A child who squints, sits close to screens, or struggles to read the board at school: Uncorrected astigmatism in childhood can contribute to amblyopia (lazy eye)

Most adults should get a comprehensive eye exam every one to two years even without symptoms. Children should have age-appropriate vision screening starting in early childhood, with repeat screening every one to two years after age 5.

Frequently Asked Questions

Can Astigmatism Go Away on Its Own?

Astigmatism rarely resolves on its own in adults. It can shift slightly in young children as the eye grows, but most people who have astigmatism will have it for life. Glasses, contacts, or surgery correct it; they do not cure it.

Does Astigmatism Get Worse With Age?

Astigmatism tends to be relatively stable, but the cornea and lens both change with age, and the prescription can drift in either direction over the years. An eye injury, eye surgery, or a condition like keratoconus can also change the curve.

Is Astigmatism the Same as Nearsightedness or Farsightedness?

No. All three are refractive errors, but they are different. Nearsightedness blurs distant objects; farsightedness blurs close objects; astigmatism blurs vision at all distances because the cornea or lens is unevenly shaped. Many people have astigmatism alongside one of the other two.

What Happens If Astigmatism Is Left Untreated?

Adults with mild, uncorrected astigmatism may have ongoing blurry vision, eye strain, and headaches but no lasting damage. In children, uncorrected astigmatism in one eye can contribute to amblyopia (lazy eye), which is why pediatric vision screenings matter.