Who Is a Good Candidate for Astigmatism Evaluation
If you notice that your vision seems blurry or slightly warped regardless of how far away an object is, you may benefit from an astigmatism evaluation. Unlike nearsightedness, which primarily affects distance vision, or farsightedness, which primarily affects near vision, astigmatism can reduce visual clarity at every viewing distance. People who frequently squint to see more clearly or who feel that their vision seems 'off' even with their current glasses may have undiagnosed or undercorrected astigmatism.
Even mild astigmatism can contribute to eye strain, headaches, and difficulty concentrating during visual tasks such as reading, working at a computer, or driving. If any of these experiences sound familiar, a comprehensive eye exam can determine whether astigmatism is playing a role.
Astigmatism can be present from birth or develop during childhood. Because children may not realize that their vision is different from what is considered typical, they may not report symptoms. Parents and teachers sometimes notice signs such as squinting, sitting unusually close to a screen or book, tilting the head to one side, or difficulty with schoolwork that involves reading or writing.
Early detection of astigmatism in children is important because uncorrected refractive errors can affect learning and development. When astigmatism is identified and corrected during childhood, it gives the visual system the best opportunity to develop properly. Your care team at Washington Eye Institute can evaluate children and recommend the appropriate corrective approach based on the child's age and visual needs.
Astigmatism frequently occurs alongside other refractive errors. It is common for a person to have both astigmatism and myopia, or both astigmatism and hyperopia. If you already wear glasses or contact lenses for nearsightedness or farsightedness but feel that your vision is still not as sharp as it should be, astigmatism may be a contributing factor that has not been fully addressed in your current prescription.
Adults who are considering refractive surgery also benefit from a thorough astigmatism evaluation. The degree and type of astigmatism you have influences which surgical approaches may be most appropriate and what outcomes you can expect. A detailed evaluation provides the information your provider needs to guide you through your options.
If your eyeglass or contact lens prescription has been changing more frequently than expected, an updated astigmatism assessment can help clarify the cause. While some prescription changes are a normal part of aging, other changes may reflect a shift in the curvature of the cornea or lens. Conditions such as keratoconus, which causes progressive thinning and steepening of the cornea, can produce increasing irregular astigmatism over time. Identifying these patterns early allows your care team to monitor your eye health more closely and intervene when appropriate.
How Astigmatism Works
To understand astigmatism, it helps to think about how a healthy eye focuses light. In an eye without refractive error, the cornea and lens have a smooth, evenly rounded curvature, similar to the surface of a basketball. This uniform shape bends light rays so they converge at a single point on the retina, producing a clear and focused image.
When astigmatism is present, the cornea or lens has an uneven curvature, shaped more like a football or the back of a spoon. Instead of bending all light rays to the same focal point, this irregular shape creates two or more focal points, either in front of the retina, behind it, or both. The result is an image that reaches the brain in a blurred or distorted form. People with astigmatism may describe objects as looking smeared, shadowed, or doubled rather than crisp and well defined.
Astigmatism can originate from either the cornea or the lens inside the eye, and in some cases from both structures simultaneously. Corneal astigmatism is the more common form and occurs when the front surface of the eye has an irregular curvature. Because the cornea is responsible for the majority of the eye's focusing power, even small variations in its shape can have a noticeable effect on vision.
Lenticular astigmatism occurs when the natural crystalline lens inside the eye has an uneven curvature. The internal lens sits behind the iris and pupil and plays a supporting role in focusing light. Lenticular astigmatism can exist on its own or alongside corneal astigmatism. During a comprehensive evaluation, your eye care provider can determine the source and degree of your astigmatism using specialized instruments, which helps guide the selection of the most effective correction method.
Eye care providers further classify astigmatism based on the pattern of the corneal or lenticular curvature. Regular astigmatism is the most common type and occurs when the two principal meridians of the eye, the steepest and the flattest, are oriented perpendicular to one another. This means one axis curves more steeply than the other at a consistent ninety-degree angle. Regular astigmatism is straightforward to correct with standard glasses, toric contact lenses, or refractive surgery.
Irregular astigmatism is less common and involves a corneal surface that curves unevenly in multiple directions without a consistent pattern. This type can result from corneal scarring, conditions such as keratoconus, or previous eye surgery. Because the distortion does not follow a predictable pattern, irregular astigmatism may not be fully correctable with standard glasses. Specialty contact lenses, such as rigid gas permeable or scleral lenses, are often more effective because they create a smooth optical surface over the cornea.
Astigmatism very commonly occurs in combination with myopia or hyperopia. When astigmatism accompanies myopia, the eye is both elongated and irregularly curved, causing blurred distance vision further complicated by distortion. When astigmatism accompanies hyperopia, the eye is both shorter than typical and irregularly shaped, affecting near vision clarity along with the distortion caused by the uneven curvature.
Your corrective prescription must account for each component separately. A prescription for someone with both myopia and astigmatism includes a spherical component to address the nearsightedness and a cylindrical component with a specified axis to address the astigmatism. Your care team measures each of these values with precision to ensure that your correction provides the clearest possible vision.
What to Expect During Your Evaluation
Refraction testing is the primary method your eye care provider uses to measure astigmatism and determine your corrective lens prescription. During this test, you look through a phoropter while your provider switches between lens options and asks which choice makes the letters on a chart appear clearer. This comparison process identifies three key values: the spherical power needed to correct nearsightedness or farsightedness, the cylindrical power needed to correct astigmatism, and the axis, which describes the orientation of the astigmatism on your eye.
Your provider may begin with an autorefractor, an instrument that takes preliminary measurements by analyzing how light reflects off the back of your eye. These automated readings provide a starting point that your provider then refines through manual refraction. If two choices look equally clear during the test, telling your provider is perfectly acceptable and helps produce an accurate result.
Corneal topography creates a detailed, color-coded map of the surface curvature of your cornea. During this painless test, you look at a target while the instrument captures thousands of data points across the corneal surface in just a few seconds. The resulting map reveals the precise shape of your cornea, highlighting areas of steepness, flatness, and any irregularities.
This test is especially valuable for distinguishing between regular and irregular astigmatism and for identifying conditions such as keratoconus that may be causing or contributing to your astigmatism. Corneal topography is also an essential step in planning refractive surgery, as it gives your provider the detailed corneal information needed to design a safe and effective treatment.
Keratometry is a focused measurement that determines the curvature of the central portion of the cornea. Using an instrument called a keratometer, your provider measures the steepest and flattest meridians of the cornea and calculates the difference between them. This difference corresponds directly to the amount of corneal astigmatism present.
Keratometry readings are essential for fitting contact lenses, planning cataract surgery, and monitoring changes in corneal shape over time. They provide a quick, reliable snapshot of corneal curvature that complements the more detailed information from corneal topography.
Depending on your symptoms, history, and initial findings, your provider may recommend additional evaluations. These can include:
- Corneal pachymetry, which measures the thickness of the cornea and is important for refractive surgery planning
- Wavefront analysis, which maps how light travels through the entire optical system of the eye and can detect subtle visual distortions beyond standard refractive measurements
- Slit lamp examination, which allows your provider to inspect the cornea, lens, and other structures under magnification to check for conditions that may be affecting corneal shape
- Dilated fundus examination, which evaluates the health of the retina and optic nerve to ensure that no other conditions are contributing to your vision symptoms
Your care team determines which tests are appropriate based on your individual situation. Every evaluation is tailored to provide the information needed for accurate diagnosis and effective management of your astigmatism.
After your evaluation, your provider will review your results and explain your prescription. An astigmatism prescription includes a cylinder value, which describes the amount of astigmatism, and an axis value, which describes the angle at which the correction must be oriented. These numbers are combined with any spherical correction you need for myopia or hyperopia to create a complete prescription. Your care team will discuss the correction options best suited to your type and degree of astigmatism so you can make an informed decision about your care.
Your Care Journey at Washington Eye Institute
Eyeglasses remain the most common and accessible method for correcting astigmatism. Lenses designed for astigmatism use a cylindrical prescription that compensates for the uneven curvature of the cornea or lens. Modern eyeglass lenses can correct a wide range of astigmatism with excellent visual clarity and comfort. For patients who also have myopia, hyperopia, or presbyopia, combination lenses such as bifocals or progressive lenses can address these needs simultaneously.
Glasses are a practical choice for patients of all ages and are especially well suited for children, for people who prefer not to wear contact lenses, and for those with higher degrees of astigmatism. Your care team can help you select the lens design and material that best balances vision quality, comfort, and durability for your daily activities.
Toric contact lenses are specifically designed to correct astigmatism. Unlike standard spherical lenses, toric lenses have different powers in different meridians of the lens and include stabilization features that keep the lens properly oriented on the eye. Soft toric lenses are the most commonly prescribed option and are available in daily disposable, biweekly, and monthly replacement schedules.
For patients with irregular astigmatism or higher degrees of astigmatism that are difficult to correct with soft toric lenses, rigid gas permeable lenses or scleral lenses may provide sharper vision. These specialty lenses create a smooth optical surface over the cornea, masking corneal irregularities. Your provider at Washington Eye Institute will recommend the lens type that best matches your prescription, corneal shape, and lifestyle.
Refractive surgery can reduce or correct astigmatism by reshaping the cornea. Procedures such as LASIK and PRK use laser energy to modify the curvature of the cornea, bringing it closer to a uniform shape that focuses light properly on the retina. These procedures can address astigmatism on its own or in combination with myopia or hyperopia.
Not every patient is a candidate for refractive surgery. Factors such as corneal thickness, the degree and type of astigmatism, overall eye health, and prescription stability all influence whether surgery is appropriate. Your care team will conduct a thorough pre-surgical evaluation and discuss the potential benefits, limitations, and expected outcomes with you before any decisions are made.
Whether your astigmatism is corrected with glasses, contact lenses, or surgery, ongoing care is important for maintaining clear and comfortable vision. Your prescription can change over time, and regular comprehensive eye exams allow your care team to update your correction as needed and monitor the overall health of your eyes.
Patients with irregular astigmatism or underlying corneal conditions may benefit from more frequent follow-up visits to track changes in corneal shape. Your care team at Washington Eye Institute will recommend a monitoring schedule tailored to your condition and adjust your management plan as your needs evolve.
One of the advantages of receiving your astigmatism care at Washington Eye Institute is access to a multi-specialty team of eye care professionals. If your evaluation reveals a condition that extends beyond routine refractive correction, such as keratoconus, corneal scarring, or a cataract contributing to lenticular astigmatism, your provider can coordinate a referral to the appropriate specialist within the same practice. This integrated approach ensures continuity of care and keeps all of your providers informed about your complete eye health history.
Whether you need a routine prescription update or a more involved evaluation for a complex form of astigmatism, your care journey is supported by a collaborative team working together on your behalf.
Questions and Answers
Astigmatism is most often related to the natural shape of the eye. Many people are born with some degree of corneal or lenticular irregularity, and mild astigmatism is extremely common. Genetics plays a significant role, so if your parents have astigmatism, you may be more likely to have it as well. In some cases, astigmatism can develop or change after an eye injury, corneal disease, or eye surgery. Your eye care provider can help determine the likely cause based on your history and diagnostic findings.
For most people, astigmatism remains relatively stable throughout adulthood, though minor changes in prescription are normal. In some cases, astigmatism can increase gradually, particularly if an underlying condition such as keratoconus is present. Regular comprehensive eye exams allow your provider to track any changes and adjust your correction accordingly. If you notice a significant or sudden change in your vision, it is important to schedule an evaluation so your care team can determine whether your astigmatism or another factor is responsible.
Astigmatism is a distinct type of refractive error, though it commonly occurs alongside nearsightedness or farsightedness. Nearsightedness causes difficulty seeing distant objects clearly, while farsightedness makes close-up vision more challenging. Astigmatism, by contrast, produces blurred or distorted vision at all distances because of the uneven curvature of the cornea or lens. Many people have a combination of astigmatism with either nearsightedness or farsightedness, and a comprehensive eye exam can identify and measure each component so that your prescription addresses all of them.
Astigmatism in children may change as the eyes grow and develop, and in some cases the amount of astigmatism may decrease over time. However, it is not accurate to say that children routinely outgrow astigmatism. Regular eye exams throughout childhood are important to ensure that any astigmatism is identified, monitored, and corrected when necessary. Uncorrected astigmatism in young children can affect visual development, so early detection and appropriate management are valuable.
Regular astigmatism occurs when the two principal curvatures of the cornea are oriented at a consistent right angle to each other. This is the most common type and can be corrected effectively with standard eyeglasses or toric contact lenses. Irregular astigmatism involves a corneal surface that curves unevenly in multiple directions without a predictable pattern. It is often associated with corneal conditions such as keratoconus or corneal scarring. Irregular astigmatism may require specialty contact lenses, such as rigid gas permeable or scleral lenses, for optimal correction. Your provider will determine which type you have based on corneal topography and other diagnostic measurements.
In most cases, yes. Standard spherical contact lenses do not correct astigmatism because they have the same power across the entire lens surface. Toric contact lenses are designed with different powers in different zones and include features that keep the lens properly aligned on the eye. Soft toric lenses are the most widely prescribed option. For patients with higher or irregular astigmatism, rigid gas permeable lenses or scleral lenses may provide better visual results. Your care team at Washington Eye Institute will evaluate your astigmatism and recommend the contact lens type that offers the best combination of clarity and comfort for your individual needs.