Astigmatism: Causes, Symptoms, and Treatment Options
What Is Astigmatism and What Causes It?
Understanding how astigmatism affects your eye is the first step toward finding the right solution. Whether you have had it since birth or developed it later in life, knowing the cause helps us guide the best treatment plan for you.
In a normally shaped eye, the cornea and lens are smooth and uniformly curved, like a basketball. This shape allows light to focus cleanly onto the retina, producing a sharp image. With astigmatism, the cornea or lens curves more steeply in one direction than the other, similar to the shape of a football.
Because light rays do not meet at a single point on the retina, your brain receives a blurred or distorted image. Straight lines may look wavy, text may appear smeared, and both near and distant objects can seem out of focus at the same time. Astigmatism frequently occurs alongside nearsightedness (difficulty seeing far away) or farsightedness (difficulty seeing up close), and your prescription will address all of these together.
Most cases of astigmatism are present from birth and have a genetic component, meaning they tend to run in families. Other causes include eye injuries, certain eye surgeries, or conditions that alter the shape of the cornea, such as keratoconus (a condition where the cornea gradually thins and bulges outward) or a pterygium (a growth on the surface of the eye).
- Family history of astigmatism or other refractive errors
- Eye trauma or scarring on the corneal surface
- Previous eye surgery or disease affecting the cornea
- Chronic eye rubbing or eyelid pressure that may contribute to corneal shape changes over time
Regular astigmatism is the most common form and occurs when the cornea curves more in one direction than the other, creating two principal meridians with different curvatures. This pattern is predictable and straightforward to correct with glasses, contact lenses, or laser surgery. Irregular astigmatism occurs when the corneal surface is uneven in multiple directions, often due to injury, scarring, or conditions like keratoconus.
Irregular astigmatism is more difficult to correct with standard eyeglasses and may require specialized contact lenses or advanced treatments. Astigmatism can also originate from the lens inside the eye rather than the cornea, though this is less common. Our team will determine which type you have during a thorough comprehensive eye exam.
Signs and Symptoms of Astigmatism
Astigmatism does not always cause obvious symptoms, particularly when it is mild. However, when symptoms are present, they can affect your comfort and ability to perform everyday tasks, and they are worth discussing with one of our eye care providers.
The most recognizable sign of astigmatism is blurred or distorted vision that affects both near and distant objects. Letters may look fuzzy, lines may appear wavy, or images may seem stretched in one direction. Unlike nearsightedness or farsightedness, which tend to affect only one distance, astigmatism can make everything look unclear at once.
Even mild astigmatism can make reading, using a computer, or recognizing faces more tiring than it should be, because your eye is constantly working to compensate for the uneven focus.
When your eyes struggle to focus clearly, the muscles around them work harder to compensate. This sustained effort can lead to tired, achy eyes, especially after extended screen time or reading. Many people with uncorrected astigmatism also experience frequent headaches, particularly across the forehead or temples.
- Squinting to temporarily improve clarity
- Frequent headaches after reading or detailed visual tasks
- Sore or fatigued eyes by end of the day
- Difficulty concentrating during close work
Astigmatism often becomes more noticeable in dim conditions. You may see halos, starbursts, or streaks around streetlights and oncoming headlights, which can make nighttime driving uncomfortable and less safe. These effects occur because the irregularly shaped cornea scatters incoming light in multiple directions rather than focusing it cleanly.
Reduced contrast sensitivity, meaning difficulty distinguishing objects against similar-colored or dark backgrounds, is another common complaint in low-light environments. If you find yourself avoiding driving after dark because of blurry or glary vision, astigmatism may be a contributing factor.
Astigmatism itself is not a medical emergency, but sudden changes in your vision always require prompt attention. Do not wait for a routine appointment if you experience any of the following symptoms, as they may signal a serious condition unrelated to your astigmatism.
- A sudden increase in blurriness or double vision
- A curtain, shadow, or dark area moving across your field of vision
- Flashes of light or a sudden increase in floaters
- Sudden loss of vision in one eye
- Significant eye pain accompanied by redness and decreased vision
These symptoms could indicate retinal detachment, acute glaucoma, infection, or corneal injury, all of which need same-day or emergency evaluation. If symptoms occur after office hours, go to an emergency room right away, and do not drive if your vision is significantly impaired.
How We Diagnose Astigmatism
Diagnosing astigmatism is a routine part of a comprehensive eye exam and involves no discomfort. Our team uses a combination of tests to measure how your eyes focus light and to evaluate the exact shape and health of your cornea.
We will start by asking about your symptoms, vision history, and any family history of eye conditions. From there, we will carry out a series of measurements designed to identify the degree and type of astigmatism you have.
- Visual acuity testing to assess how clearly you see at various distances
- Refraction testing to determine your precise corrective lens prescription
- Keratometry or corneal topography to map the curvature of your cornea
- A full evaluation of your eye structures and overall eye health
During refraction testing, you will look through a device called a phoropter, which holds a series of different lenses, while we ask you which options make the eye chart look clearest. This simple process allows us to pinpoint the exact prescription that corrects your astigmatism. We may also use an autorefractor, an instrument that shines a light into your eye and automatically estimates your prescription, as a helpful starting point before the manual test.
Your astigmatism prescription will include a cylinder power (the degree of correction needed) and an axis measurement (the direction of the correction), which together tell the lab precisely how to shape your lenses.
For a more detailed picture of your corneal shape, we may use corneal topography or tomography, imaging technologies that create a color-coded map of the cornea's surface and internal structure. These tools reveal even subtle irregularities in curvature that standard testing alone might not detect.
Advanced corneal imaging is especially important if you are considering laser vision correction or if we suspect a condition like keratoconus. The maps allow us to track changes over time, customize your treatment plan, and confirm that surgical options are safe and appropriate for your eye anatomy.
Non-Surgical Treatment Options for Astigmatism
Most people with astigmatism manage their vision very successfully with non-surgical correction. The right option for you will depend on your prescription, lifestyle, and personal preferences, and our team will walk you through each choice in detail.
Eyeglasses are the most straightforward way to correct astigmatism. Your lenses will be made with a special cylindrical prescription that compensates for the uneven curvature of your cornea or lens. The prescription specifies both the cylinder power and axis so the lenses are shaped precisely to deliver your clearest vision.
Depending on your prescription and daily activities, we may recommend full-time wear or glasses for specific tasks such as reading, driving, or computer work. Most people adapt to their new lenses within a few days, though it is normal for your brain to take up to a week to fully adjust to the corrected image.
If you prefer contacts, toric soft lenses are designed specifically to correct astigmatism. These lenses have different focusing powers in different meridians and a built-in stabilization system that keeps them properly oriented on your eye. For higher degrees of astigmatism or irregular corneal shapes, rigid gas permeable lenses, scleral lenses, or hybrid lenses can provide sharper, more consistent vision.
- Soft toric lenses for mild to moderate astigmatism
- Rigid gas permeable lenses for higher or irregular astigmatism
- Scleral lenses that vault over the cornea for complex or irregular prescriptions
- Hybrid lenses with a rigid center and soft outer edge for a balance of clarity and comfort
- Daily disposable and monthly replacement options available
Proper contact lens hygiene is essential for protecting your eye health. Always wash your hands before handling lenses, replace your lens case regularly, never expose lenses to water, and only sleep in lenses if your provider has specifically instructed you to do so.
Orthokeratology, commonly called Ortho-K, uses specially designed rigid contact lenses that are worn overnight to gently and temporarily reshape the cornea while you sleep. When you remove them in the morning, your vision is clearer throughout the day without needing glasses or daytime contacts. This non-surgical and fully reversible option can be particularly appealing for active individuals, children, and adults who are not ready for surgery.
Because the reshaping effect is temporary, the lenses need to be worn regularly (most nights) to maintain results. Ortho-K requires a custom fitting, strict lens hygiene, and regular follow-up visits to monitor your corneal health and ensure the correction remains safe and effective. As with any overnight lens wear, there is a greater risk of eye infection if hygiene protocols are not followed carefully.
Surgical Treatment Options for Astigmatism
For patients who want to reduce or eliminate their dependence on glasses and contact lenses, surgical options may be worth exploring. Candidacy depends on the type and degree of astigmatism, the health of your cornea, and other individual factors that our team will evaluate thoroughly before making any recommendation.
LASIK is a commonly performed laser procedure that reshapes the cornea to correct astigmatism, often at the same time as nearsightedness or farsightedness. During the procedure, a thin flap is created in the outer corneal tissue, a laser removes a precise amount of tissue to reshape the curvature, and the flap is repositioned to heal naturally. Many patients notice significantly improved vision within a day or two of surgery.
Good LASIK candidates generally have stable vision, adequate corneal thickness, and realistic expectations about outcomes. Not all types or degrees of astigmatism are appropriate for LASIK, and irregular astigmatism in particular is often not suitable for this approach. Corneal topography and tomography are used to check for ectasia risk (a condition where the cornea becomes too thin and may bulge forward), assess dry eye status, and confirm eligibility before surgery is recommended.
Photorefractive keratectomy, or PRK, reshapes the cornea using a laser without creating a flap. Instead, the outer cell layer of the cornea is gently removed before the laser is applied. PRK may be a better option for patients with thinner corneas or certain lifestyle considerations that make LASIK less suitable.
Other refractive procedures include LASEK and SMILE (small incision lenticule extraction), which is commonly used for myopia with astigmatism. Topography-guided or wavefront-guided treatments can address certain corneal irregularities in select cases, and candidacy depends on the specific pattern and severity of astigmatism. Our team will explain the recovery timeline and expected outcomes of each option so you can make a confident, well-informed decision.
If you have both astigmatism and cataracts (clouding of the natural lens inside the eye), we can address both conditions in a single procedure by implanting a toric intraocular lens (IOL). Toric IOLs have built-in astigmatism correction and are carefully aligned with your corneal curvature during surgery, which can significantly reduce or eliminate your need for glasses after recovery.
In some cases, your surgeon may combine cataract surgery with limbal relaxing incisions, which are small, precise corneal incisions that help reshape curvature for additional astigmatism correction. Our surgical team will discuss which approach best fits your prescription and eye anatomy.
Not everyone is a suitable candidate for refractive surgery, and your safety always comes first. We may recommend against surgery if certain conditions are present that affect eligibility or increase surgical risk.
- Unstable or fluctuating vision prescription
- Thin or irregularly shaped corneas that increase ectasia risk
- Active eye infection or significant inflammation
- Autoimmune or systemic conditions that affect healing
- Age under 18, when the eyes are still developing and the prescription may still be changing
- Pregnancy, nursing, or uncontrolled diabetes
Managing Astigmatism Over Time
Whether you choose glasses, contacts, or surgery, ongoing care plays an important role in keeping your vision clear and your eyes healthy. Astigmatism can change gradually over the years, so staying on top of your eye exams and maintaining good habits matters.
It is common to need a brief adjustment period when starting a new astigmatism prescription, especially if this is your first correction or if your prescription has changed significantly. You may notice mild distortion at the edges of new glasses lenses or slight dizziness at first. These sensations typically resolve within a few days as your brain adapts to the clearer images.
If discomfort persists beyond a week, or if your vision does not seem quite right, reach out to our office. A small refinement to your prescription or lens fit can make a meaningful difference in your daily comfort.
Astigmatism can shift gradually over time, and your prescription may need updating even if you are not aware of a change. Most adults benefit from a comprehensive eye exam every one to two years, while children and individuals with certain risk factors (including rapidly changing prescriptions or eye conditions) may need to be seen more frequently.
If you notice new blurriness, increased headaches, or worsening eye strain between your scheduled visits, do not wait. Getting an updated prescription promptly can restore clear vision and prevent unnecessary discomfort.
Taking care of your eyes between appointments helps you get the most out of your correction and supports long-term eye health. Small daily habits can add up to a meaningful difference over time.
- Take regular screen breaks using the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds
- Wear sunglasses with UV protection whenever you are outdoors
- Keep your hands and contact lenses clean to reduce infection risk
- Avoid rubbing your eyes, as chronic rubbing may contribute to corneal shape changes over time
- Eat a balanced diet that includes nutrients known to support eye health, such as leafy greens, omega-3 fatty acids, and vitamins C and E
Recovery timelines differ depending on which procedure you have. After LASIK, many patients notice significantly improved vision within one to two days, though full stabilization can take several weeks. PRK has a longer initial recovery, with meaningful improvement over the first week and continued healing over a few months.
It is common to experience temporary dry eye, mild glare, and halos around lights in the weeks following surgery. Less common but more serious risks include infection, corneal ectasia, flap complications with LASIK, corneal haze with PRK, and the possibility of under-correction or over-correction requiring a follow-up enhancement. Some patients may still need glasses for certain activities, particularly near tasks as they age. We will schedule follow-up visits to monitor your healing and address any concerns promptly.
Frequently Asked Questions
Here are answers to some of the questions our patients ask most often about astigmatism, covering decisions, expectations, and practical next steps.
In most cases, astigmatism does not resolve without treatment because it is determined by the physical shape of your cornea or lens. Very mild astigmatism in young children occasionally improves slightly as the eyes develop, but this is the exception rather than the rule. For the vast majority of people, some form of correction is needed to achieve clear, comfortable vision throughout life. If you are unsure whether your level of astigmatism requires correction, a comprehensive exam will give you a definitive answer.
Astigmatism can remain stable for many years, but it may also change gradually, particularly as the cornea and lens naturally shift with age. Certain eye conditions, like keratoconus, can cause astigmatism to progress more noticeably over time. This is why regular monitoring matters even when you feel your vision has not changed. Catching a shift early allows us to update your prescription before the change significantly affects your daily life.
Standard spherical contact lenses are not designed to correct astigmatism because they apply uniform correction across all meridians of the lens and cannot compensate for the directional differences in corneal curvature. If you try to wear them with astigmatism, your vision is likely to remain blurry or fluctuate throughout the day. Toric lenses, rigid gas permeable lenses, or scleral lenses are the appropriate contact lens solutions, and the best fit depends on your prescription and corneal shape. Our optometry team can guide you through the fitting process.
Many vision insurance plans cover eyeglasses and contact lenses for astigmatism, though the amount covered varies by plan and provider. Refractive surgery such as LASIK or PRK is typically considered elective and is generally not covered by medical or vision insurance, though some plans offer discounts or allow the use of flexible spending accounts (FSAs) or health savings accounts (HSAs) to help with costs. We recommend reviewing your specific plan details or speaking with our team about financing options available to you.
Yes, and treating astigmatism in children is important for healthy visual development. Significant uncorrected astigmatism in young children can lead to amblyopia, commonly called lazy eye, where the brain begins to favor the better-seeing eye and vision in the other eye does not develop properly. Glasses are typically the first-line treatment for children, and some may transition to contact lenses as they mature. Refractive surgery is generally not recommended until the late teens or early twenties, when the eyes have finished growing and the prescription has been stable for at least two years.
A standard glasses prescription corrects for nearsightedness or farsightedness by adjusting focus either closer or farther away. Astigmatism adds a directional component to the correction, because the eye does not focus evenly across all angles. This is why astigmatism prescriptions include both a cylinder power and an axis measurement, in addition to the sphere power for nearsightedness or farsightedness. Many people have all three components in their prescription at the same time, and a well-fitted pair of glasses or toric contact lenses can address all of them together.
See Clearly with the Right Care
If blurry vision, headaches, or eye strain is affecting your daily life, our team at Rhode Island Eye Institute is here to help. We offer comprehensive astigmatism evaluations and a full range of treatment options tailored to your vision needs, lifestyle, and goals. Serving patients across Rhode Island and southeastern Massachusetts, we are committed to providing expert, compassionate eye care that makes a real difference in how you see the world.