Astigmatism sounds like something serious, and it's often mispronounced as "stigma" or "stigmata," which doesn't help. In reality, it just describes the shape of your eye, and it's one of the most common, easily corrected things we see.
Astigmatism is a word that does itself no favours. It sounds clinical and a little alarming, and we've actually heard it mispronounced as "stigma" or "stigmata" more than once. Let's take the scare out of it: astigmatism simply describes the shape of your eye. A perfectly round eye, like a football, focuses light evenly from every direction. An astigmatic eye is shaped a little more like a rugby ball, curving more steeply in one direction than another.
That's really it. It's one of four common refractive errors, alongside myopia, hyperopia and presbyopia. It's not a disease, it's not a sign your eye health is at risk, and it's extremely common; most people have at least a small amount of it. It's simply a shape that needs to be accounted for when correcting your vision.
Clear vision depends on light converging to a single sharp point on the retina. In myopia or hyperopia, that point simply falls in front of or behind the retina, but it's still one point. With astigmatism, the eye's uneven curvature means light entering different directions focuses at more than one point instead of one, so the retina never receives a single, sharp image.
This is why astigmatism often looks and feels a little different to other refractive errors: rather than everything looking uniformly soft, images can appear stretched, doubled, or have streaking around lights, especially at night. Corrected properly, it resolves just as reliably as any other refractive error.
If you've seen your glasses prescription and wondered what all the numbers mean, astigmatism is usually the reason there's more than one. A typical prescription with astigmatism looks something like -3.00 / -1.75 x 180, and each part describes something different about your eye.
The sphere. This is the short- or long-sightedness component, myopia if it's a minus number, hyperopia if it's a plus number.
The cylinder. This is the amount of astigmatism being corrected, always written as its own separate number.
The axis. This describes the direction of the astigmatism, measured in degrees from 0 to 180.
Astigmatism is always defined by this axis, so no two astigmatic prescriptions are quite the same. It can sit horizontally, vertically, obliquely, or anywhere in between, which is why the axis number matters just as much as the amount.
Astigmatism doesn't only come from one place in the eye, and it rarely occurs on its own. One location, the cornea, is far more common than the other, and it's also frequently combined with short- or long-sightedness rather than appearing in isolation.
By far the most common source, this comes from the shape of the cornea, the clear front surface of the eye. This is the astigmatism most people are referring to when the word comes up.
Less commonly, the uneven curvature sits further inside the eye, in the natural crystalline lens rather than the cornea. It produces the same kind of blur but is measured and managed slightly differently.
Astigmatism very commonly occurs together with myopia or hyperopia rather than on its own, since an eye can be unevenly curved and also too long or too short at the same time. A pure, standalone case of astigmatism with no other refractive error is the less common presentation. Most prescriptions reflect this combination, which is written as two separate measurements, one for the astigmatism and one for the short- or long-sightedness, both are corrected together in the same pair of glasses or contact lenses.
Astigmatism is corrected by counteracting the eye's uneven curvature with a lens shaped to match it, known as a toric lens. We offer several ways to do this.
A completely standard part of a spectacle lens. A toric lens is ground with different curvature in different directions to counteract the eye's own uneven shape, giving sharp, single-point focus. See our eyewear collection.
Soft contact lenses correct astigmatism the same way, using a toric design that sits on the eye. Standard toric soft lenses typically correct up to around -2.25D of astigmatism, which covers the majority of prescriptions. Explore our astigmatism contact lens options.
Overnight lenses that gently reshape the cornea while you sleep, correcting astigmatism without glasses or daytime contacts. See how OrthoK works for astigmatism below.
For astigmatism beyond what standard toric lenses can handle, custom-made soft lenses extend correction much further. Our Mark'ennovy lens range can correct astigmatism up to -8.00D, opening up soft lens options for prescriptions that would otherwise need a rigid lens.
For high or irregular astigmatism, custom rigid, hybrid or scleral lenses can achieve sharper correction than soft lenses alone. See when a specialty lens is the better fit below.
OrthoK can successfully correct low to moderate astigmatism in most cases, and we fit many astigmatic patients with OrthoK for glasses- and contact lens-free vision during the day. Rather than a one-size-fits-most design, an OrthoK lens for astigmatism is customised with different curves to match the difference in corneal curvature across the astigmatic cornea, ensuring the lens seats accurately and reshapes the cornea evenly overnight.
This customisation is exactly the kind of fitting work we do regularly, and it's part of why OrthoK remains a practical option for the majority of astigmatic patients we see, not just those with a perfectly round cornea. Find out more on our OrthoK page.
When a child or teenager has astigmatism alongside myopia, the astigmatism itself usually isn't the pressing concern, the myopia is. Left untreated, the myopia component will typically continue to progress as the eye grows, so myopia management is worth considering in exactly the same way it would be for a young patient with myopia alone.
Specialised lenses that correct both the myopia and the astigmatism as standard, while also slowing myopia progression. A straightforward option for most young astigmatic patients. See our myopia control glasses.
A particularly good option for active kids and those who dislike wearing glasses. OrthoK slows myopia progression and, in most cases, corrects both the myopia and the astigmatism overnight, with clear vision all day and nothing to wear. Find out more on our OrthoK page.
Low-dose atropine drops slow myopia progression but don't correct the astigmatism itself, so glasses or contact lenses are usually still needed alongside them for clear vision. Learn more about atropine eye drops.
Popular soft myopia management lenses such as MiSight and Abiliti don't correct astigmatism, so they're only suitable where there's no astigmatism or a very small amount. For children and teens with more significant astigmatism, myopia control glasses, OrthoK or atropine are generally more appropriate, and OrthoK in particular can address both the myopia and the astigmatism together in most cases.
Not every astigmatic eye is best served by glasses, soft lenses or OrthoK. Higher or irregular astigmatism sometimes needs a different approach entirely.
Where astigmatism is high, rigid lenses are often the better option. A rigid lens holds its own shape rather than flexing to match the eye, effectively creating a new, smooth optical surface over the irregular cornea for sharper vision than a soft lens can usually achieve at higher amounts.
Some astigmatism is irregular rather than smooth and predictable, and can progressively worsen. The most common cause is keratoconus, where the cornea gradually thins and steepens unevenly. These cases generally can't be fully corrected with glasses or standard soft lenses and usually require custom rigid lenses.
Depending on your eyes, this might mean rigid gas permeable lenses, hybrid lenses, or scleral lenses, each suited to different degrees and types of corneal irregularity. We assess which is right for you based on your specific corneal shape.
This page is an overview. For a deeper look at any part of the astigmatism picture, start here.
A closer look at toric soft lens options and how we fit them, including custom high-power designs.
Read more →How overnight OrthoK lenses work, who's a good candidate, and how customised designs correct astigmatism too.
Read more →What causes irregular, progressive astigmatism, how it's detected early, and how it's managed long-term.
Read more →See how astigmatism compares with myopia, hyperopia and presbyopia, and how each affects vision differently.
Read more →Whether you've just heard the word astigmatism for the first time or you're exploring contact lens or OrthoK options for an existing prescription, a comprehensive eye test is the place to start. We'll map your exact corneal shape and talk through the correction options that suit you.