Football season has officially begun! Fall weather, team spirit, and… astigmatism? Have you ever had an eye doctor tell you that you had football shaped eyes? Sometimes, eye doctors use the analogy of a football when describing a condition known as astigmatism. Rather than the eye being perfectly round, like a basketball, when eyes have astigmatism they are more curved or shaped more like a football. Does this mean eyes with astigmatism are literally shaped like a football? No, it does not. Astigmatism is somewhat difficult to describe, so this analogy is just a simple way to explain the condition. So, what does astigmatism actually mean?
To fully understand astigmatism, it helps to know a little bit of eye anatomy. Light enters the eye through the cornea. The cornea is the clear outer covering of the eye that helps light focus within the eye. Light then travels through the pupil of the eye and is focused by the lens. The lens of the eye could be compared to a camera lens. Just as we zoom a camera lens in when we’re looking up close or zoom out when looking at something in the distance, the lens of the eye adjusts its shape to allow us to see things clearly depending on where we are looking. In an eye with perfect vision, the lens will then correctly focus light onto the retina in the back of the eye. This focused light is then sent to the brain where we interpret the light as images. Unfortunately, sometimes the power of the eye is too weak or too strong or the shape of the eye is longer or shorter than normal. When the combined power of the cornea and lens is too strong or if the eye is too long, this makes a person nearsighted. This means that light is focused in front of the retina rather than directly on the retina. A nearsighted person can see clearly up close, but things in the distance are blurry. Someone who is farsighted has the opposite problem. The power within their eyes is too weak and unable to focus on objects up close. Glasses and contact lenses are used to make both near and far-sighted people’s vision clear by refracting light and moving it to the correct place on the retina. So what about astigmatism?
Astigmatism usually occurs because the cornea has an irregular shape. Rather than focusing light in one spot, it usually focuses light in two different places within the eye. Sometimes it focuses light both in front of and behind the retina at the same time. You can imagine how this would make your vision blurry. It can also focus light in two different locations in front of the eye which makes one nearsighted and astigmatic, or two places behind the eye making one farsighted and astigmatic. Fortunately, astigmatism is usually easily corrected with glasses and even contact lenses in most cases. In fact, the majority people’s eyeglass prescriptions have at least some astigmatism correction because most peoples’ corneas vary a bit in shape. Hopefully this helps explain astigmatism a bit more. You can probably see now why optometrists sometimes simplify astigmatism by calling eyes “football shaped.”