Astigmatism (often called “stigma” or “stigmatism”) is one of the most common vision problems, and it can be fully corrected with glasses, contact lenses, or surgery. It happens when your cornea, the clear front surface of your eye, is curved more like a football than a basketball. This uneven shape bends light unevenly, so instead of focusing to a single sharp point on the retina, light splits into two focal lines, causing blurry or distorted vision at all distances.
What Causes Astigmatism
Most astigmatism is corneal, meaning the front surface of the eye has one meridian that curves more steeply than the other. You can also have lenticular astigmatism, where the lens inside the eye is tilted or unevenly curved, though this is less common. Some people are born with it, while others develop it after an eye injury, surgery, or conditions like keratoconus (a progressive thinning of the cornea).
Even everyday factors play a role. Eyelid pressure, the pull of the muscles around your eye, and habitual squinting can all influence corneal shape over time. A chalazion (a bump on the eyelid) or a pterygium (a growth on the eye’s surface) can press on the cornea enough to create or worsen astigmatism. Contact lens wear can also temporarily warp the cornea, a phenomenon called contact lens warpage.
How It’s Diagnosed
An eye care provider measures the curvature of your cornea using a keratometer, a device you look into while it projects rings of light onto your eye and calculates how steeply each meridian curves. Many offices now use corneal topography, which creates a detailed color map of the entire corneal surface. This is especially useful for detecting irregular astigmatism that a standard test might miss. Your prescription will include three numbers: a sphere power (for nearsightedness or farsightedness), a cylinder power (the amount of astigmatism), and an axis (the angle, from 1 to 180 degrees, where the astigmatism sits).
Glasses and Standard Contact Lenses
For most people, the simplest fix is a pair of glasses with cylindrical lenses built into the prescription. The cylinder power targets the specific meridian where your cornea curves too steeply, bending light back to a single focal point.
If you prefer contacts, toric lenses are the standard option. Unlike a regular spherical contact lens that has a uniform curve, a toric lens has two different curvatures, one for the sphere correction and one for the cylinder. Because astigmatism has a specific direction, the lens must sit at the correct angle on your eye. Toric lenses use stabilization features like thin zones or weighted edges to keep them from rotating out of position when you blink.
Scleral Lenses for Irregular Astigmatism
When astigmatism is irregular, caused by keratoconus, corneal scarring, or a prior corneal transplant, standard glasses and toric contacts often can’t fully sharpen vision. Scleral lenses are a specialized option for these cases. They’re larger than typical contacts and vault completely over the cornea, resting on the white of the eye (the sclera) instead. The space between the lens and the cornea fills with a thin layer of fluid that essentially creates a new, smooth optical surface, neutralizing the uneven curvature underneath.
Newer designs use wavefront-guided optics and custom-shaped edges fitted from detailed scans of the eye’s surface. These lenses have reduced the number of people who need corneal transplant surgery for conditions like keratoconus.
Laser Surgery: LASIK, PRK, and SMILE
Laser procedures reshape the cornea permanently, eliminating or reducing astigmatism so you no longer need glasses or contacts. The three main options differ in how they access the corneal tissue.
LASIK creates a thin flap on the cornea’s surface, reshapes the tissue underneath with an excimer laser, then replaces the flap. It can correct up to 6.0 diopters of astigmatism (the unit used to measure refractive error). A large meta-analysis of FDA-approved LASIK devices found that 97% of patients achieved vision of 20/40 or better without glasses, and 62% reached 20/20.
PRK removes the outermost layer of the cornea entirely instead of creating a flap, then reshapes the tissue with the same laser. It treats the same range of astigmatism as LASIK. Recovery takes longer because the surface layer needs to regenerate, but PRK is a better choice for people with thinner corneas or jobs where a flap could be risky.
SMILE uses a femtosecond laser to create a small disc of tissue (called a lenticule) inside the cornea, which the surgeon removes through a tiny incision. It’s approved for up to 3.0 diopters of astigmatism. Research comparing SMILE to LASIK shows they perform similarly for high astigmatism (above 3.0 diopters), but LASIK tends to be slightly more precise for low-to-moderate amounts. Both procedures can slightly undercorrect high astigmatism, which sometimes means a touch-up procedure using PRK.
To qualify for any of these surgeries, your prescription needs to have been stable (changing no more than 0.5 diopters) for at least a year. Minimum age requirements vary: 18 for LASIK and PRK, 21 for mixed astigmatism correction, and 22 for SMILE.
What Recovery Looks Like
After LASIK, expect stinging and burning for two to four hours. Most people wake up the next morning with noticeably clearer vision and no need for glasses. The first week calls for precautions: no eye makeup, no swimming for two weeks, and a follow-up visit to check healing. For most people, the eyes are fully healed within a month, though it can take three to six months for vision to completely stabilize. Some people notice mild fluctuations in clarity during that window, which is normal.
PRK recovery is slower. The surface layer of the cornea takes several days to grow back, and vision may be blurry for one to two weeks. Full stabilization follows a similar three-to-six-month timeline.
Toric Implants During Cataract Surgery
If you have both cataracts and astigmatism, a toric intraocular lens (IOL) can correct both problems in a single procedure. During cataract surgery, the clouded natural lens is removed and replaced with an artificial one. A toric IOL is shaped to compensate for your corneal astigmatism, and the surgeon uses corneal topography data to align it to the correct axis. These implants have been available since 1998 and are now widely used. One limitation: most toric IOLs don’t correct presbyopia (age-related difficulty with close-up reading), so you’ll likely still need reading glasses afterward.
Can Eye Exercises Fix Astigmatism?
No. Astigmatism is a structural issue, the physical shape of your cornea or lens. Eye exercises cannot reshape the cornea. Claims that relaxation techniques, eye yoga, or focus-shifting drills can cure astigmatism have no scientific support. These exercises may reduce eye strain from screen use, but they won’t change your prescription. The only ways to correct astigmatism are optical (lenses that redirect light) or surgical (physically reshaping the cornea or implanting a corrective lens).