Astigmatism is one of the types of refractive error, similar to myopia (nearsightedness) and hyperopia (farsightedness). It is one of the causes of blurry vision that can be corrected with glasses.
Astigmatism refers to the cornea (the clear “front window” of the eye) not being perfectly rounded—or not equally curved in every axis, but rather is more steeply curved at one axis and flatter at another. For instance, if you think of a clock face, the cornea may be more steeply curved along the 12 o’clock (vertical) axis and flatter along the 3 o’clock (horizontal) axis. The job of the cornea is to bend light to help put it in focus for clear vision. A cornea with astigmatism bends light coming in at different axes differently, so it will not be well focused and vision will not be clear. Special glasses lenses are required to account for the astigmatism and provide clear vision.
Many corneas have some astigmatism (un-roundness or irregular shape). This is very common and is not a disease—it’s just how many of our corneas are shaped. Like nearsightedness or farsightedness, astigmatism can be corrected to some extent with corrective lenses.
Cataract surgery and astigmatism
Standard cataract surgery does not fix astigmatism, but if your astigmatism isn’t addressed at the time of cataract surgery, it is more likely that glasses will be needed for your best vision after surgery.
There are several ways of correcting astigmatism during cataract surgery. However, correcting astigmatism is considered “refractive” surgery because it is not correcting a disease, but rather is intended to reduce the likelihood that you will need to wear glasses for best vision after surgery. Therefore, many insurances do not pay for the portion of the procedure that corrects astigmatism. Insurances will still pay for cataract surgery and the cost of a standard intraocular lens implant at the time of cataract surgery, but most will not pay for astigmatism correction, so the fee for that portion of the procedure would be your responsibility. It is okay to choose cataract surgery without astigmatism correction. Astigmatism correction is an option.
Options for correcting astigmatism during cataract surgery
Toric intraocular lens implants
A special type of lens is strategically positioned to compensate for or correct your astigmatism.
Astigmatism relaxing incisions
Incisions are made across the steeper axis of the cornea to “round it up,” which reduces the difference in steepness between axes, rounding out or reducing the astigmatism and thereby reducing your need for glasses. This adds very little surgical time or risk and does not tend to complicate healing. Dr. Quinn will do measurements and calculations to make the correct incisions.
Laser procedures on the cornea (such as LASIK)
No option is guaranteed to have a perfect outcome. For any refractive surgery, it is possible that we will not get exactly what we aim for and you will still see best when you wear glasses. However, your chances for getting the best vision without glasses increase if you choose a surgical astigmatism correction option.
For more information:
Eye Care Center
Winona Health, Clinic 3rd floor
859 Mankato Avenue
Winona, MN 55987
8 a.m.–5 p.m. Monday–Friday