What is astigmatism? This is a question many have for one of the most common vision problems. At least 30% of the US population has some level of astigmatism. We will answer everything you need to know about astigmatism in this blog. Yes, it is “astigmatism” not “stigmatism” as it is commonly referred to. You don’t have “a stigmatism”...you have astigmatism.
What is Astigmatism?
Similar to nearsightedness and farsightedness, astigmatism is a refractive error. It is simply a problem with how the eye focuses light. It is not a disease or eye health problem.
Astigmatism results from an imperfect curvature of the cornea or lens. Typically, the cornea and lens surfaces have a symmetrically round curvature (like a basketball). This allows light rays to be sharply focused to a single focal point on the retina. With astigmatism, there is an “out-of-roundness” that produces multiple focal points, either in front of the retina or behind it (or both). This results in a blurry image.
How is Astigmatism Diagnosed?
Astigmatism is diagnosed during a routine eye examination, which includes the following:
• Visual acuity: determines the clarity and sharpness of your vision
• Keratometry or topography: measures the shape of the cornea
• Refraction: determines how the eye focuses light
The results of these tests determine the corrective lenses that allow light rays to be sharply focused to a single focal point on the retina, resulting in clear vision.
How is Astigmatism Treated?
1. Eyeglasses are the simplest correction, as the appropriate lens will be prescribed to correct the specific level of astigmatism.
2. Contact lenses of an appropriate power and curvature can be prescribed to correct a specific level of astigmatism.
3. LASIK can be used to correct astigmatism similar to how it can correct nearsightedness and farsightedness.
4. Toric intraocular lens implants can be used during cataract surgery to correct one’s astigmatism.