What is Astigmatism and Can LASIK Treat It?

In short, yes. Astigmatism can be treated by the LASIK treatments of today. Astigmatism is not an abnormal eye health condition; rather, it is a refractive error of the eye. In fact, it is quite common. About 1 in 3 people that wear glasses or contacts have astigmatism. There is a common misconception that you cannot have LASIK if you have astigmatism, but this could not be farther from the truth.

To best understand astigmatism and how it relates to one’s vision, one must first understand some of the basics of the optics of the human eye. When a person sees clearly at a distance without an eyeglass prescription, they are emmetropic. Emmetropic means that the light entering their eye(s) from a distance focuses clearly to a single point onto the retina, allowing them to see clearly.

When light hits an oblique surface, like the lens of an eye, it bends and changes paths. This is known as refraction of light. When you go to the eye doctor, they often perform a certain test known as a refraction. This is the famous “what is better, 1 or 2?” test that is often portrayed in the media. A refraction test helps determine a person’s eyeglass prescription by examining their refractive error, or the reason why light is unable to focus to a single point onto that eye’s retina without glasses.

There are three primary refractive errors that cause light to not focus properly. The first two refractive errors are nearsightedness and farsightedness. Nearsightedness (myopia) occurs when light focuses too soon and comes to a point focus in front of the retina. Nearsighted eyes do not see well far away, and these patients have a minus sign in front of their eyeglass prescription. Farsightedness (hyperopia) means light focuses too late, meaning that light comes to a point focus behind the retina. Farsighted eyes thus do not see as well up close, and these patients will have a plus sign in front of their eyeglass prescription.

The third refractive error is astigmatism, which causes light to not come to a focus point anywhere on the retina. Instead, light becomes unequally focused on two separate lines. For this reason, astigmatism means “without a focal point.”

Astigmatism can be corneal or lenticular, meaning one or both of these two primary refractive parts of the eye are not spherical or are shaped more like a football. The lack of a spherical shape causes the light passing through the cornea and lens to not focus correctly on the retina. In essence, astigmatic eyes have two different primary refractive errors. That is why patients with astigmatism have very different-looking eyeglass prescriptions from patients that don’t have astigmatism.

Example of a Non-Astigmatic Eyeglass Prescription: -2.50 SPH (Sphere)

Example of an Astigmatic Eyeglass Prescription: -2.50 -1.25 x 180

In the astigmatic prescription above, in addition to the myopic -2.50 part of the prescription, the -1.25 x 180 part of the prescription represents the amount and orientation of the astigmatism. Fortunately, astigmatism is correctable by LASIK. The Excimer Laser used in LASIK procedures can successfully reshape the cornea to treat all kinds of astigmatism. Modern advanced LASIK technology has corrected tens of millions of eyes with astigmatism around the world.

At 20/20 Institute, we assist patients tired of the limitations eyeglasses and contact lenses place on their everyday lives. We perform Advanced Custom LASIK that treats all three types of refractive errors, whether that is myopia, hyperopia, or astigmatism. Our unsurpassed visual outcomes mean that 99.67% of our Denver LASIK patients have achieved 20/20 or better vision*. If you’re ready to explore your options related to LASIK surgery in Denver, schedule one of our complimentary LASIK phone consults to discover if LASIK can free you from the daily hassles of glasses and contacts.