Q: I’ve heard various explanations, but not really sure what this vision problem is, and does it get worse over time?
A: So glad you asked, as this must be the most common question asked of eye doctors since time began! In our clinic, I explain this many times every single day.
Let me explain the major vision disorders. Nearsightedness and farsightedness are named for your better vision. Sort of backwards, as most medical conditions are named for the problem…..these are named for your best eyesight. Nearsighted people have eyes that grew too long…..like an egg, not a ping pong ball…and see better up close. Farsighted folks have eyes that are too short, and see better far away. Both conditions make your vision focus either too soon or too late to be in sharp focus on your retina. Glasses and contact lenses simply change the focus of our incoming vision, moving the sharp focal point either further back or closer to the front of our eyes.
How Astigmatism Affects Vision?
Astigmatism is different but is the most common vision disorder of all. This is just a different kind of eyesight blur, not a disease at all. This blurring of vision is sometimes noticed as a distortion or smearing of vision. For instance, you might see the vertical part of the letter E clearly, but the horizontal parts are not distinct. There are countless variations on this distortion.
The causes of astigmatism are one or two anatomical variations. One, the front surface of our eyes may not be perfectly round, but rather “bent” like the back of a spoon. This bent shape also makes our vision focus imperfectly. Two, the crystalline lens inside our eye may be “bent” as well. Some people have one tissue misshaped, while others have both. Nonetheless, both are nicely corrected with glasses or contact lenses.
Can Astigmatism Get Worse?
Lastly, most people have both near- or far-sightedness plus some form of astigmatism. And does it get worse over time? Not necessarily. In fact, it is totally unpredictable…….getting worse over time for some, and getting better for others. Genetics likely control this lifelong change, but clearly change is not caused by how you use your eyes! I must add that astigmatism can be the primary indicator of corneal diseases like keratoconus. This is especially true for younger patients ( teens through 30 ) who are developing increasing astigmatism at a rapid rate. Using corneal topography, we can sort out “healthy” astigmatism from the disease-caused disorders.
Our vision never stops changing. Most people have some vision prescription change every year throughout their life. We prescribe based on the amount of change and the patient’s symptoms.
