Astigmatism Explained: Symptoms, Causes, and How Glasses Help
If your optometrist has ever told you that you have astigmatism, you are in good company. It is one of the most common vision conditions, yet it is also one of the most misunderstood. A lot of people hear the word and assume something is wrong with their eyes beyond just needing glasses.
The truth is much simpler. Astigmatism just means your eye is shaped a little differently than a textbook eye, and it is easy to correct once you know what is going on.
Here is what astigmatism actually is, what causes it, and how the right pair of glasses fixes it.
What Astigmatism Actually Is
A healthy eye is shaped like a basketball, perfectly round in every direction. An eye with astigmatism is shaped more like a football, curved more in one direction than another. That uneven curve means light entering your eye focuses on more than one point instead of a single sharp point, which is what makes things look blurred or slightly distorted at any distance, up close or far away.
Astigmatism almost always exists alongside nearsightedness or farsightedness rather than on its own, which is why it shows up on your prescription as a CYL and AXIS number alongside your regular SPH correction.
Common Symptoms
Astigmatism symptoms are often subtle enough that people live with them for years without realizing something is correctable. The most common signs include:
Blurred or slightly distorted vision at any distance
Headaches, especially after reading or screen time
Eye strain or discomfort by the end of the day
Difficulty with night vision, like halos around lights while driving
Squinting to bring things into focus
None of these symptoms are dramatic on their own, which is exactly why astigmatism often goes undiagnosed until a routine eye exam catches it.
What Causes It
Astigmatism is almost always something you are born with, caused by the natural shape of your cornea or lens. It is not caused by reading in dim light, sitting too close to the television, or spending too much time on screens, despite the old myths. It can also develop or change slightly after an eye injury or surgery, but for most people it is simply genetic, the same way eye color or height is.
It is also not a disease and does not get progressively worse the way some eye conditions do. It can shift slightly over the years the way your overall prescription does, which is part of why regular eye exams matter.
How It's Diagnosed
Astigmatism is identified during a standard, comprehensive eye exam using the same equipment and process as checking for near or farsightedness. There is no separate test or extra appointment needed. Your optometrist measures exactly how much astigmatism you have and at what angle, which becomes the CYL and AXIS numbers on your prescription.
How Glasses Correct Astigmatism
Lenses for astigmatism are ground with a specific curve that offsets the irregular shape of your eye, redirecting light back to a single, sharp focus point. This is precisely why your prescription includes an AXIS number. It tells the lab exactly which direction, in degrees, that correction needs to be oriented in the lens so it lines up correctly with your eye.
Modern lenses correct astigmatism just as effectively and comfortably as they correct any other prescription. The days of astigmatism meaning thick, heavy lenses are long gone. Most people find the adjustment seamless, especially with properly fitted frames.
Astigmatism and Contacts vs. Glasses
Astigmatism can be corrected with either glasses or contacts, though contacts require a specific type called toric lenses, which are designed the same way as astigmatism glasses lenses, with a built-in orientation that has to stay properly positioned on the eye. Glasses are generally the simpler, more forgiving option since the lens orientation never shifts once it is in the frame.
FAQs
Does astigmatism get worse over time?
It can shift slightly as you age, similar to your overall prescription, but it is not a progressive disease and does not typically worsen dramatically on its own.
Can kids have astigmatism?
Yes, astigmatism is common in children and is usually caught during routine childhood eye exams. It is corrected with glasses the same way it is in adults.
Do I need special lenses for astigmatism?
Your lenses simply need the correct CYL and AXIS measurements ground into them. No special lens type is required, and nearly all frame styles can accommodate an astigmatism prescription.
Can I just ignore mild astigmatism?
Very mild astigmatism may not need correction if it is not affecting your daily vision, but your optometrist is the best judge of whether correcting it will make a noticeable difference for you.
Think You Might Have Astigmatism?
If headaches, night driving glare, or blurry close-up vision sound familiar, it might be time for an eye exam.
Book an exam with us, and we will check for astigmatism as part of every routine visit, and help you find frames that pair well with your prescription.
Book your eye exam online at 3for1glasseshamilton.com/book-your-exam, or stop by our Upper James St location on Hamilton Mountain.
Visit 3 for 1 Glasses - Hamilton
1550 Upper James St, Hamilton, ON L9B 2L6
Phone: 905-383-1467
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