JUST WHAT IS THIS ASTIGMATISM STUFF?
A condition of being without a brand or mark. Huh? That's according to a strict definition of "stigma" or "stigmata" by Webster and his dictionary. Then you must add the "a-", meaning without, and the "-ism", meaning a condition of, and put it all together. Already confused? Me too.
Let's stay with the football and the egg. If you have astigmatism, there is a good chance that your cornea (the front, clear part of the eye) has an irregular shape, much like a football or an egg. This is in contrast to a golf ball shape which is SPHERICAL. Actually, let's use a ping-pong ball and an egg. (Most corneas don't have those dimples) The ping-pong ball is a regular, spherical object, where as the egg has an irregular, cylindrical surface. The cornea that resembles the egg will have astigmatism, and the cornea that resembles the ping-pong ball will probably not. Getting any easier yet?
OK, don't give up yet, it gets better. If you ran your finger across the surface of a ping-pong ball in any direction, the curvature is the same. Now try this with an egg. As you run your finger across the "long" portion of the egg, you can feel a gradual curve. Now check it the "short" direction and you will notice a lot more curvature. Again, the ping-pong ball represents a spherical cornea without astigmatism, and the egg represents a cylindrical cornea with astigmatism.
I would have to guess that about 70% of all eyes have, at least, a small amount of astigmatism. If the astigmatism is mild, as in most cases, the patient may not even be aware of it. It will be the moderate to severe astigmatic cases that need help. If you had no other refractive problem (nearsightedness or farsightedness) but your astigmatism was significant, you will see blurry at ALL DISTANCES. Things would appear "ghosty" or double, or just plain blurry. It also creates an internal "focusing battle" inside the eye that may lead to fluctuating vision, eye strain or headaches. I have seen patients that even develop a slight head tilt to compensate for their astigmatism.
Myopia, or nearsightedness, affects FAR vision; hyperopia, or farsightedness, affects NEAR vision. Astigmatism affects ALL vision. The silver lining in astigmatism is the fact that it affects your far vision about HALF as much as being myopic of the same degree. It also CANCELS some of the effect of being hyperopic. So, I guess our egg-shaped corneas aren't all that bad! By the way, if you tend to forget if you are nearsighted or farsighted, think of it this way: nearsighted = "sighted at near", but blurry at far. Farsighted = "sighted at far", but blurry at near. See how easy this stuff is?
And remember, astigmatism is a CONDITION of the eyes. It's not a case where you might have an astigmatism in one eye and two or three in the other. It's a little like conjunctivitis in that regard, you don't have two or three of them, you have the condition of CONJUNCTIVITIS, period.
Astigmatism can be corrected quite easily with glasses or contact lenses. Excimer laser surgery is also an option in certain cases. Just as the cornea is stronger (more curved) in one direction, the corrective lens must also be stronger in that direction. This is why we must use astigmatic or "toric" soft lenses on patients with astigmatism. They are "weighted" in a special way as to correctly align the different powers on that contact lens with different powers on that cornea. Glasses work the same way. Try tilting your glasses (if you have astigmatism) and see what happens to your vision.
Astigmatism is very common and quite harmless, but it's always good to have a little knowledge of where it comes from….it comes from eggs! Anyone for Eggs Benedict?