Astigmatism is extremely common. Most people have at least some degree of it. According to the American Academy of Ophthalmology, the majority of people have between 0.5 and 0.75 diopters of astigmatism, a mild amount that often doesn’t require correction. Only when the measurement reaches about 1.5 diopters or higher do most people need glasses or contacts to see clearly.
How Many People Have It
Almost no one has a perfectly round cornea, which means almost no one has zero astigmatism. The question isn’t really whether you have it, but whether you have enough to notice. Roughly half of all adults over 40 have astigmatism greater than 0.5 diopters, and about one in four have it above 1 diopter. Severe astigmatism, above 3 diopters, is much rarer, affecting around 3 to 4% of adults.
For most people, astigmatism is mild enough that they may never realize they have it. Their eyes compensate, or the blur is so slight it doesn’t interfere with daily life. It’s the people in the 1.5-diopter-and-above range who typically start noticing blurred or distorted vision at certain distances, headaches, or eye strain.
Astigmatism at Different Ages
Astigmatism is surprisingly common in babies. A large study of young children in Los Angeles found that 25% of African American infants and 40% of Hispanic infants between 6 and 11 months old had significant astigmatism (1.5 diopters or more). By the time those children reached age 5 or 6, prevalence dropped to about 11% in both groups. This pattern is well established: many infants are born with astigmatism that naturally resolves as the eye develops during the first few years of life.
In adults, the trend reverses. Astigmatism tends to increase again with age, particularly after 40. The type of astigmatism also shifts. Younger people tend to have what’s called “with-the-rule” astigmatism, where the cornea is steepest along the vertical axis. As people age, the steepest curve rotates toward the horizontal axis. In one study of adults aged 40 to 64, this age-related pattern nearly doubled in prevalence between the early 40s and early 60s.
Who Gets It More Often
Ethnicity plays a role in how common astigmatism is, especially in children. Hispanic children have consistently higher rates than other groups. In the Multi-Ethnic Pediatric Eye Disease Study, 16.8% of Hispanic children overall had clinically significant astigmatism compared to 12.7% of African American children. Studies of non-Hispanic white and Asian children have found overall rates around 6 to 8% at the same threshold, though Asian children tend to have higher rates of nearsightedness instead.
Genetics is a major factor regardless of ethnicity. If your parents have astigmatism, you’re more likely to have it too. There’s no single gene responsible; it’s influenced by multiple genetic factors that shape corneal curvature.
The Difference Between Regular and Irregular Types
The vast majority of astigmatism is “regular,” meaning the cornea is shaped like a football: curved more steeply in one direction than the other, but in a consistent, predictable way. This is what glasses and standard contact lenses correct easily.
Irregular astigmatism is far less common and harder to correct. It occurs when the cornea’s surface is uneven in unpredictable ways, creating distortions that standard lenses can’t fully fix. The most common cause is keratoconus, a condition where the cornea progressively thins and bulges outward. Irregular astigmatism can also result from corneal scarring after infections or injuries, and occasionally from eye surgeries, particularly full-thickness corneal transplants. Specialty rigid contact lenses are typically needed to correct it because they create a smooth optical surface over the irregular cornea.
Astigmatism Alongside Other Vision Problems
Astigmatism rarely exists in isolation. It commonly occurs alongside nearsightedness or farsightedness. In children, farsightedness is the most common refractive error overall, and many of those same children also have some degree of astigmatism. In adults, the combination of astigmatism with nearsightedness is particularly common, especially in populations with high myopia rates.
Having astigmatism alongside another refractive error doesn’t make either condition worse, but it does mean your prescription needs to account for both. Your glasses or contacts will correct the overall focusing error and the directional distortion from astigmatism at the same time.
How It’s Corrected
Glasses are the most common and straightforward fix. The lens is shaped to compensate for the uneven curvature of your cornea, bending light so it focuses properly on the retina. Toric contact lenses do the same thing but sit directly on the eye, with a design that keeps them oriented correctly so the correction stays aligned with your astigmatism axis.
Laser eye surgery is an option for people who want a more permanent solution. For those undergoing cataract surgery, astigmatism can be corrected at the same time using specially designed lens implants. A large analysis of nearly 40,300 eyes during cataract procedures found that about 60% of eyes with low astigmatism were left uncorrected during surgery, suggesting that many surgeons and patients decide mild amounts aren’t worth the added complexity of correction.
Astigmatism under 0.5 diopters generally doesn’t need any correction at all unless you’re experiencing eye strain or headaches. If you’ve been told you have astigmatism, the number that matters most is your cylinder measurement on your prescription. The higher it is, the more noticeable the blur and the more benefit you’ll get from correction.