Astigmatism

A common vision problem caused by an irregularly shaped cornea, resulting in blurred vision at all distances.

Published: June 23, 2025
Last reviewed by: Leightons Clinical Team
Last reviewed: February 12, 2026

Astigmatism is a common refractive error - when the shape of your eye prevents light from focusing correctly on your retina. It’s a common cause of blurry vision but, thankfully, can be diagnosed and treated with the use of corrective lenses. Read on to learn more about astigmatism and how it can be corrected.

Blurred vision of a room.

 

What is astigmatism?

Astigmatism happens when your eyes aren’t completely round. Usually, eyeballs are round and shaped like footballs. Astigmatism happens when the shape of your eye looks more rugby ball-shaped. This can either happen gradually over time or is something you can be born with.

It’s a very common refractive error. The irregular shape of your eye means that light entering your eye doesn’t focus correctly on your retina which can cause blurry vision, distorted images, and starburst effects when looking at bright lights.

 

Types of astigmatism

Regular astigmatism

A healthy eye has a spherical cornea or lens, meaning the curves around the entire eye are the same. An eye with astigmatism, however, has a steep curve and a flat curve, also known as the two principal meridians.

Regular astigmatism happens when the two principal meridians are 90 degrees apart, with one meridian steeper than the other. This type of astigmatism is the most common type and can be corrected by glasses, contact lenses, or laser surgery.

Regular astigmatism can also be described as either “with-the-rule” or “against-the-rule” depending on which way the steepest angles of your eye face. With-the-rule astigmatism means your eye is shaped like a rugby ball lying on the ground with the steepest curves running vertically and is most common in younger people. Against-the-rule astigmatism means your cornea is shaped like a rugby ball on its end with the steepest curves running horizontally and is more common in older adults.

Keratoconus - eye disease, thinning of the cornea in the form of a cone.

Irregular astigmatism

Where regular astigmatism occurs when the two principal medians are always at right angles, irregular astigmatism happens when the two principal medians are not symmetrical. The curvature of your cornea is uneven. This type of astigmatism is harder to correct than regular astigmatism.

Irregular astigmatism is usually caused by disease such as keratoconus (gradual thinning of the cornea), corneal degeneration, corneal scarring, or ocular surface disease.

 

Astigmatism combined with refractive errors

You can also have astigmatism combined with other refractive errors. In a normal eye, the meridians work together to focus light into a single point on the retina. When you have astigmatism, the eye cannot focus light on a single point and instead creates two focal points. Combine that with other refractive errors like myopia – nearsightedness or hyperopia – farsightedness, and it’s likely that you’ll need corrective measures like glasses, contact lenses, or laser eye surgery.

Simple myopic: The combination of astigmatism and nearsightedness in which one focal point comes before the retina, while the other is on the retina.

Compound myopic: A combination of astigmatism and nearsightedness in which both focal points fall before the retina.

Mixed: The combination of astigmatism, nearsightedness and farsightedness in which one focal point is before the retina and the other focal point is behind the retina.

Simple hyperopic: A combination of astigmatism and farsightedness in which one focal point is on the retina while the other is behind the retina.

Compound hyperopic: A combination of astigmatism and farsightedness in which both focal points are behind the retina.

 

Causes of astigmatism

We know that astigmatism is caused by a cornea or lens that has a different shape than normal. It can be inherited – it may be present from birth or develop later in life – or it may develop after an eye injury, disease or surgery. Astigmatism isn't caused or made worse by reading in poor light, sitting too close to the television or squinting.

The OCT scan for an ultimate eye test at Leightons

 

Diagnosing astigmatism

Astigmatism is diagnosed through comprehensive eye exams. A complete eye exam such as Leightons’ Ultimate Eye Exam involves a series of tests to check eye health and refraction – which determines how the eyes bend light.

Your optometrist may use various instruments, aim bright lights directly at your eyes and ask you to look through several lenses to examine different aspects of your eyes and vision, and to determine the prescription needed to provide clear vision with glasses or contact lenses.

 

 

Treatment options

There are multiple options available for helping to correct astigmatism.

Glasses: one of the most common ways to fix astigmatism. They contain a cylindrical lens that compensates for the uneven curves in your cornea or lens. People with severe astigmatism may be better suited for glasses instead of contacts. This is often one of the most cost-effective options although wearing glasses can be inconvenient depending on your lifestyle.

Contact lenses: offer similar benefits of glasses but sit directly on your eye. Whether you are offered soft or hard contact lenses will depend on your prescription and severity of astigmatism so it’s worth speaking to your optician about your options. Contact lenses are another cost-effective option but aren’t available for very severe prescriptions and aren’t ideal for those who don’t like touching their eyes.

Refractive surgery: A surgery procedure that helps to improve vision and reduces the need for glasses or contact lenses. Your eye surgeon will use a laser beam to reshape the curves of the cornea, which corrects the refractive error and can be very effective for many people. Surgery can be expensive as it’s not typically offered on the NHS and comes with more complications than other methods of treatment. However the effects can be permanent and may be more suited to those with more severe vision problems.

There is no one “right” way to correct astigmatism. You should choose the method that works best for your prescription, your lifestyle, and your comfort levels. Speak to your optometrist and optician to help find the best solution for you.


Silver glasses, black and case glasses and microfiber cloth inside of case.

Managing astigmatism

If you’ve been diagnosed with astigmatism, it’s, thankfully, easy to manage from here on.

Make sure you are scheduling regular eye exams to keep an eye on the condition and catch any changes in your vision early. You can book your eye tests through Leighton’s directly.

Ensure you are taking proper care of your glasses – storing them in a scratch proof case when not in use and cleaning them regularly – and understand the importance of safe contact lens use to reduce the risk of introducing bacteria to your eye.

Eye-healthy lifestyle habits can also help manage your symptoms including eating a nutritionally balanced diet and avoiding eye strain – making changes to your screen usage where possible, reading in well lit areas, and ensuring you take regular breaks.

 

Conclusion

Astigmatism is a very common vision problem but is one that can be easily and effectively corrected through a variety of different treatment options. If you suspect you might have astigmatism, or have experienced a change in your vision, reach out to your local eye care professional to determine the best treatment approach for your needs.

You may also like

Visual stress
Visual stress
If you find reading uncomfortable, notice words moving on the page, or feel strain when looking at patterns or screens, you may be experiencing visual stress. Visual stress is a common but often overlooked condition that can affect how comfortable your vision feels, particularly when reading or focusing for longer periods. With the right support, it can often be managed effectively, helping you feel more relaxed and confident in your day-to-day vision. If your symptoms are linked to light or contrast, you may also find it helpful to explore how tinted lenses can improve visual comfort and clarity.   What is visual stress? Visual stress, sometimes referred to as Meares-Irlen syndrome, affects how the brain processes visual information. It is not a problem with your eyesight itself, but rather how your eyes and brain work together when looking at text, patterns or bright environments. People with visual stress often find that certain visual tasks feel overwhelming or uncomfortable, even if their vision has been tested and appears normal.   Common symptoms of visual stress Visual stress can present in different ways, and symptoms may vary from person to person. You may notice: Words appearing to move, blur or distort on the page Difficulty tracking lines of text when reading Sensitivity to bright light or glare Headaches or eye strain when reading or using screens Letters or patterns appearing to flicker or shimmer Reduced concentration when reading for longer periods These symptoms can make everyday tasks feel more tiring, particularly in environments with bright lighting or high contrast.   What causes visual stress? The exact cause of visual stress is not always clear, but it is linked to how the brain processes visual patterns and contrast. High contrast patterns, such as black text on a white page, can sometimes feel overwhelming for the visual system. This can lead to discomfort, distortion or fatigue when reading or focusing for extended periods. Visual stress is often noticed in both children and adults, particularly when reading feels difficult or tiring. It is sometimes associated with conditions such as dyslexia, although the two are not the same.   Visual stress vs light sensitivity: what’s the difference? Visual stress and light sensitivity can feel similar, but they are not the same. Light sensitivity (photophobia) is typically linked to brightness and discomfort from light itself Visual stress is more closely related to patterns, contrast and how visual information is processed Some people experience both, which is why a thorough assessment is important to understand what is affecting your vision.   Can tinted lenses help with visual stress? For many people, tinted lenses can make a noticeable difference to visual comfort. Carefully selected colours can help reduce the intensity of contrast and visual patterns, allowing your eyes to feel more relaxed when reading or using screens. This can make text appear more stable and easier to follow. The effect of colour is highly individual, which is why it is important to find the right tint for you rather than choosing a general option. Colour selection is typically guided through a visual stress assessment*. During an appointment, you may be shown a range of coloured overlays or lenses and asked to read or focus on text, helping you experience which tones feel most comfortable. Explore the different colours and types of tinted lenses to understand how each option works.   What is a visual stress test? At Leightons, there are two main types of visual stress assessment, designed to understand how your eyes respond to colour and contrast. Coloured overlay assessment: Different coloured overlays are placed over text to identify which makes reading feel more comfortable. Any improvement is measured using a standardised reading test. If effective, you may get specialised, custom-tinted lenses to use for reading and school/work. Colorimetry: A more advanced assessment using a specialist device to identify the precise tint or colour combination needed to reduce visual stress. This allows for the prescription of precision-tinted lenses tailored to your individual visual response. Before considering a visual stress assessment, it is important to have a comprehensive eye examination. This allows us to check your overall eye health and ensure your symptoms are not being caused by something else, such as: A prescription change Eye strain Another underlying eye condition If appropriate, we can then guide you through a visual stress assessment to explore whether coloured lenses may help improve your comfort and clarity.   Managing visual stress in everyday life There are several ways to help reduce the impact of visual stress in your daily routine: Use softer, more consistent lighting Reduce glare from screens Take regular breaks when reading or working Adjust screen settings or use coloured backgrounds For many people, the most effective support comes from personalised solutions such as coloured overlays or tinted lenses tailored to your visual needs. If your symptoms are linked to screen use, it may also help to compare blue light vs tinted lenses to understand which option is most suitable.   When should you seek advice? If reading feels uncomfortable, or if symptoms are affecting your concentration or confidence, it is worth having your eyes assessed. The best place to start is with a full eye examination. This allows us to understand your vision in detail and rule out any underlying causes. From there, we can guide you towards the most appropriate support, including whether tinted lenses or a colourimetry assessment may be beneficial. Book your eye test today.   * Please note that not all Leightons practices offer coloured overlay assessments or colourimetry. Please contact your local branch to confirm availability.
Learn more
Right Arrow
Navigation Previous
Navigation Next