Astigmatism (or “the stigmatism!!!”) is a common topic of discussion in my exam room. Many people have heard about it, report a family history and believe they have it in their glasses prescription. Conversely- many patients report suffering from symptoms of uncorrected astigmatism in their vision and are unaware that their visual problems could be fixed with simple glasses prescription. Let’s get to it and explain what astigmatism is, what are some common symptoms of astigmatism, and what are some ways in which we can help relieve the visual stresses of this refractive error.
Astigmatism is a refractive error. That means that the light entering your eye is not properly focused on the retina so instead of a crisp, clean image you wind up with a blur circle and subsequent blurry, strained vision. Many of you have probably heard that an astigmatic eye is shaped more like a football than a basketball. While this can be true and is an easy visualization, that is not always the case. The cornea and lens work together to focus light on your retina and the cause of refractive error is often something other than an irregularly shaped cornea. I prefer to explain it this way: in an astigmatic eye, the light rays that come in vertically are focused differently than the horizontal rays entering the eye 90 degrees away. That means the light going up and down may have a prescription of -1.00 and the light coming into the SAME EYE horizontally might have a prescription of -2.00. Sometimes the rays are not perfectly vertical or horizontal or vertical and you have a unique cylinder axis in your written prescription. (that last number on your vision prescription!) Rarely, the lines out of focus are not 90 degrees apart. These are unique cases … but it’s still the exact same thing: Astigmatism is when there is more than one power of prescription within one eye. Plain and simple.
Astigmatism can be benign (and usually is) or caused by disease processes which affect the shape of your cornea. It is impossible to discern the cause of astigmatism without a full eye exam. One thing we can address are some common symptoms and complaints relative to astigmatism. First and foremost- headlights at night. Patients with astigmatism will often complain that headlights while driving at night are extremely bothersome. Another complaint I hear is “my eyes hurt/strain when I’m on the computer”. This is becoming so common due to the increased role computers, tablets and phones have in our society. Young workers and students of all ages frequently say their eyes are uncomfortable on the computer or when they read. Often, these patients have otherwise perfect vision but are straining when working on computer screens. One other big sign of uncorrected astigmatism is when someone tells me they see better when they squint. Remember me saying that light is coming in and focusing in different places for patients with astigmatism? Squinting eliminates one point of light that is out of focus and eliminates the blur circle. Think of it as shutting the blinds on a really bright morning and making the amount of light coming in much more manageable.
Astigmatism without underlying disease is a very simple condition to treat. We treat astigmatism with glasses or contact lenses. Contacts are more difficult to fit since they actually rotate on the cornea but in most cases we can find a comfortable fit that corrects your vision with a little trial and error. Astigmatism is usually a benign condition that can be corrected with a simple glasses or contact lens prescription. If you are suffering from any of the symptoms above please contact our clinic and we will set up an exam to see if you have astigmatism and if we can do anything to help!