Astigmatism is a common refractive error that can cause blurry or distorted vision. It happens when the cornea or lens of the eye has an irregular shape, causing light to be refracted unevenly as it enters the eye. While it’s a condition easily diagnosed with an eye exam, distinguishing it from regular refractive errors like myopia (nearsightedness) or hyperopia (farsightedness) can help you understand your symptoms better.
This blog will help you identify whether you might have astigmatism by discussing the physical symptoms and how to read your prescription. We will also explain how prescription eyeglasses can correct this condition and help improve your vision.
Physical Symptoms of Astigmatism vs. Regular Eye Prescription
Astigmatism affects your vision differently from other refractive errors like myopia or hyperopia. While some symptoms overlap, there are clear distinctions in how each condition impacts your vision.
1. Blurry or Distorted Vision
1. Astigmatism: The primary symptom of astigmatism is blurry or distorted vision. Since the cornea or lens is shaped irregularly, light entering the eye doesn’t focus evenly, leading to unclear vision at both near and far distances. Straight lines may appear wavy or uneven, and objects might look distorted, especially when reading small text or viewing objects like windows.
2. Regular Eye Prescription (Myopia or Hyperopia): Myopia causes blurry vision for distant objects (like street signs or the television), while hyperopia results in blurry vision for nearby objects (such as reading a book). These refractive errors don’t distort objects—they simply blur them depending on the distance from your eyes.
Key Difference: Astigmatism causes distortion and blurriness at all distances, while regular vision problems typically blur images at specific distances.
2. Frequent Eye Strain and Discomfort
1. Astigmatism: Eye strain is a common symptom of astigmatism. Since the eye is constantly working harder to compensate for the irregular curvature, focusing on objects for extended periods can lead to discomfort, especially during activities like reading, driving, or working on a computer.
2. Regular Eye Prescription (Myopia or Hyperopia): People with myopia or hyperopia may also experience eye strain, but it’s usually associated with specific tasks—like trying to see objects far away (myopia) or focusing on close-up text (hyperopia).
Key Difference: Astigmatism typically causes more frequent and persistent strain, as the eyes must focus on both near and far objects. Myopia or hyperopia-related strain occurs when focusing on one distance.
3. Headaches
1. Astigmatism: Regular headaches, especially around the eyes or temples, are common for people with astigmatism. This happens because the eyes are exerting more effort to focus, which can lead to tension and discomfort in the head.
2. Regular Eye Prescription (Myopia or Hyperopia): Headaches in myopia or hyperopia tend to occur less often and are generally related to specific activities like reading or driving, where the eyes are under strain to focus at a particular distance.
Key Difference: Headaches caused by astigmatism are typically more frequent and constant, as the eyes struggle to maintain clear focus at multiple distances.
4. Squinting and Double Vision
1. Astigmatism: Squinting is a common response to astigmatism. By narrowing the eyelids, squinting temporarily reduces the distortion and helps focus. People with astigmatism may also experience double vision, where objects appear to overlap because light is refracted in different directions.
2. Regular Eye Prescription (Myopia or Hyperopia): Squinting can also occur with myopia or hyperopia, but it’s generally to adjust vision at a specific distance (near or far). Double vision is rarer in myopia and hyperopia, as these conditions usually cause a single, blurred image rather than multiple overlapping images.
Key Difference: Double vision and frequent squinting are more characteristic of astigmatism, while squinting in myopia or hyperopia is usually limited to specific tasks.
How to Read Astigmatism on Your Prescription
If you have astigmatism, your prescription will include specific measurements to correct the condition. Understanding how to read your prescription can help you identify astigmatism and other refractive errors:
1. Cylinder (CYL) Value: The cylinder value in your prescription indicates the degree of astigmatism. It will be listed in the “CYL” column and is measured in diopters (D). The higher the value, the more severe the astigmatism.
2. Axis: This number represents the orientation of the astigmatism, measured in degrees from 1 to 180. It tells your optometrist where the curvature is located on your eye.
3. Spherical (SPH) Value: This indicates whether you are nearsighted (myopia) or farsighted (hyperopia). If you have both astigmatism and a regular refractive error, both the CYL and SPH values will appear on your prescription.
For example:
1. OD (right eye): -2.50 SPH, -1.00 CYL, 90° axis
2. OS (left eye): -2.25 SPH, -1.25 CYL, 85° axis
This means the person has myopia and astigmatism in both eyes. The cylinder and axis values will correct for the astigmatism, while the spherical values correct for nearsightedness.
Correcting Astigmatism with Prescription Eyeglasses
Astigmatism can be easily corrected with prescription eyeglasses. These glasses are specially designed to address the irregular curvature of your cornea or lens. By incorporating cylindrical lenses, prescription glasses for astigmatism help to focus light evenly on the retina, allowing for clearer vision at all distances.
Prescription lenses for astigmatism will often have special coatings or materials to make them more comfortable and effective. For example, high-index lenses can help make your glasses thinner, and anti-glare coatings can improve visibility in various lighting conditions.
Conclusion
Astigmatism presents distinct symptoms, such as blurry or distorted vision, headaches, eye strain, and double vision, that can be differentiated from regular refractive errors like myopia and hyperopia. If you experience these symptoms, it’s important to schedule an eye exam to determine the cause.
Whether you’re dealing with astigmatism alone or alongside other refractive errors, prescription glasses are a practical solution for improving vision and easing discomfort.
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Matt is a passionate woodworker, father of four, and number cruncher by day. His love for woodworking was sparked by his great-grandfather's carpentry legacy and nurtured by his dad's DIY spirit. Encouraged by his wife, Matt turned his woodworking hobby into a successful side hustle, focusing on creating custom cutting boards and engaging with a thriving online community. Now, he's shifting gears to share his knowledge and passion through Borkwood Blog, where he hopes to inspire and connect with fellow woodworking enthusiasts.
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