Astigmatism is a common refractive error that occurs when the cornea, or the eye’s lens, is shaped irregularly, affecting how light focuses through the eye.
Yes, astigmatism can cause headaches, eye strain, and blurry vision at all distances. Fortunately, it can be corrected with eyeglasses, contact lenses, or refractive surgery, which can alleviate these symptoms.
What Is Astigmatism?
Astigmatism is a refractive error like myopia (nearsightedness) or hyperopia (farsightedness) that occurs in approximately 1 in 3 people. Astigmatism occurs when the shape of the eye is irregular. A normal eye is round and shaped like a basketball. With astigmatism, the shape of the eye changes, becoming oval-shaped like a football.
When the eye is round, internal structures like the cornea and the lens have an even round shape. When light enters the cornea, it bends to focus on the retina, helping us see clearly.
Astigmatism can be caused by either the cornea or the lens of your eye having an irregular shape. When these structures become oval-shaped, light rays don’t bend properly as they enter the cornea and cannot focus on the retina. This leads to blurry vision.
Vision can be blurry at both near and far distances depending on whether the light rays fall short of or behind the retina. Individuals with astigmatism may also have additional refractive errors, such as myopia or hyperopia.
Symptoms that suggest an individual may have an astigmatism include:
- Blurry or distorted vision at any distance
- Eye strain
- Headaches
- Squinting
- Difficulty with night driving due to halos and light glare
Some individuals may experience light symptoms of astigmatism or no symptoms at all. Visiting your optometrist for routine eye exams can help determine if you have an astigmatism.
What Causes Astigmatism?
The irregular shape of the cornea or the lens of the eye causes astigmatism. Currently, we are unsure what causes this irregular shape.
Most people are born with astigmatism, which is diagnosed in childhood during a comprehensive visit. However, adults may independently develop astigmatism. Like myopia and hyperopia, astigmatism can change over time.
Several factors can increase your risk of developing astigmatism:
- Family history of astigmatism
- Corneal scarring
- Corneal thinning
- High myopia
- High hyperopia
- Keratoconus
Astigmatism can worsen over time due to factors such as:
- Aging: The cornea can change its shape as we age.
- Eye injuries: Foreign objects, chemical burns, or side effects after eye surgery can damage the cornea, lens, or retina.
- Keratoconus: An ocular condition that causes your cornea to become thinner and weaker.
How Is Astigmatism Diagnosed?
Your optometrist can diagnose astigmatism based on a series of tests conducted during your comprehensive eye exam, which is important for maintaining healthy vision and ocular health.
Before visiting your optometrist in the exam room, a series of preliminary tests will typically be conducted to give a baseline assessment of your eye health and vision prescription.
An autorefractor provides an estimate of your vision prescription and keratometry values. Keratometry helps determine the curvature of your cornea and measures astigmatism.
Inside the exam room, your optometrist will conduct a series of tests to determine your vision prescription. A phoropter is a measurement tool used to determine the severity of potential refractive errors, such as astigmatism, myopia, and hyperopia.
During a comprehensive eye exam, you can receive a prescription to help correct any refractive errors, such as astigmatism.
How Is Astigmatism Corrected?
Fortunately, astigmatism is not typically a serious eye condition. It can be corrected with tools like glasses, contacts, or refractive surgery like LASIK or PRK. When astigmatism is corrected, its symptoms, like blurry vision, eye strain, and headaches, can subside.
If left uncorrected, symptoms like headaches, blurry vision, and eye strain may persist. Uncorrected astigmatism can lead to serious ocular conditions like amblyopia (lazy eye) and vision loss.
The optimal plan for correcting your astigmatism will consider your lifestyle, personal preference, and advice from your optometrist.
Corrective Lenses
Eyeglasses are the most common and noninvasive approach to correcting astigmatism. The lenses in your glasses correct how light enters the cornea and focuses on the retina, resulting in clear vision.
Contact lenses are also a common way to correct astigmatism. They are slightly more invasive than eyeglasses, as the corrective lens sits comfortably on top of the cornea. Finding the right contact lenses for your prescription may require trial and error.
There are a variety of contact lenses that can help correct for astigmatism. Your optometrist will recommend the best option for you:
- Toric lenses: These are specialized soft contact lenses designed for astigmatism.
- Rigid gas-permeable contact lenses: These are hard contact lenses that maintain their shape while on the cornea. These are usually recommended for patients who have more severe astigmatism.
Refractive Surgery
Refractive surgeries like LASIK and PRK offer a more permanent approach to correcting astigmatism (and other refractive errors). These procedures help reshape the cornea to adjust how light enters the eye and focuses on the retina, typically resulting in clear vision without needing glasses or contacts.
Unfortunately, not everyone is a good candidate for refractive surgery. Several factors, including the strength of your prescription, determine a patient’s candidacy for surgery. Consult your optometrist to learn if refractive surgery will work well for you.
Schedule Your Visit With Us!
Visiting your optometrist for routine eye exams is important for maintaining healthy vision and ocular health. Astigmatism is a common refractive error that can be corrected in several ways. While it’s not often serious, leaving astigmatism uncorrected can lead to vision complications.
If you’re experiencing any symptoms of astigmatism, such as headaches, blurry vision, or eye strain, contact our team to schedule your next eye exam.
