Astigmatism

How does astigmatism affect your vision? 

Astigmatism often causes blurry vision, especially around the edges of what you're looking at. It can make your vision look distorted or stretched out, a bit like looking in a funhouse mirror. Things might seem out of focus, and straight lines might look wobbly or slanted. Some people with astigmatism notice halos around lights, especially when driving at night. Things might seem out of focus, especially around the edges. You might notice it more when reading small text or switching between near and far. If you’ve got astigmatism in both eyes, it can affect your depth perception too, making things feel just a bit “off”. Some people also report eye strain or a slight sense of imbalance, especially without the right lenses. 

Different types of astigmatism

There are various types of astigmatism, based on which part of the eye it affects: 

1. 1.

   Corneal astigmatism: This happens when the cornea, the clear, curved surface at the front of your eye, isn’t evenly rounded. Instead of being shaped like a football, it’s more like a rugby ball, which bends light unevenly and makes your vision appear blurry or distorted.

2. 2.

   Myopic astigmatism: This is a type of astigmatism where part of the eye is short‑sighted. That means light focuses in front of the retina, which can make things look blurry, especially at a distance. If both directions of the eye’s curve are short‑sighted (but to different levels), it’s called compound myopic astigmatism. 

3. 3.

   Hyperopic astigmatism: In this case, part of the eye is long‑sighted, which means light focuses behind the retina. If both directions of the eye’s curve are long‑sighted, but to different degrees, it’s called compound hyperopic astigmatism. If just one eye is affected, it’s simple hyperopic astigmatism. This can make nearby things look blurry or harder to focus on. 

4. 4.

   Mixed astigmatism: With this type, one direction of the eye is short‑sighted, and the other is long‑sighted. That mix makes it hard for your eyes to focus clearly, whether something’s near or far. It can cause general blur and distortion at all distances.

How is astigmatism diagnosed?

When you come in for an eye test, your optometrist will ask about your vision and talk through anything you've noticed, like blur, glare or tired eyes. 

One of the early checks we do is with an autorefractor, a machine that shines a light into your eye and measures how it bounces back. It helps us spot if your eye is focusing light differently in different directions, which could suggest astigmatism. 

We may also do what’s called a retinoscopy. That’s where your optometrist uses a small torch‑like device to shine a light in your eye and watch how it reflects. It’s a quick and clever way to check how your eye bends light and how much correction might be needed. 

Then there’s the Jackson cross cylinder test. You’ll be shown two different lenses and asked which one is clearer. It helps us fine‑tune your prescription and work out the best lens to correct any astigmatism.

Can astigmatism be prevented? 

You can’t prevent astigmatism, but keeping an eye on your vision and booking regular eye tests is the best way to make sure your eyes stay healthy. There is also evidence to show that excessive rubbing of the eyes can lead to the development or worsening of astigmatism. 

Changes in your eyesight can happen slowly, so regular eye tests mean we can spot any issues early and update your prescription if needed. If you wear glasses or contacts, this also helps keep your vision sharp and comfortable. 

What happens if astigmatism isn’t treated? 

Astigmatism isn’t an eye disease; it’s a refractive error, which just means your eye isn’t focusing light properly. But if it’s not picked up or corrected, especially in children, it can lead to other issues over time, including: 

• Lazy eye (amblyopia): If only one eye is affected, the brain might start to rely more on the clearer one. Over time, the weaker eye can become less active, also known as amblyopia or lazy eye. Regular eye tests for kids help spot this early. 

• Strabismus (squint): Uncorrected astigmatism can sometimes cause the eyes to work unevenly. This extra strain can lead to misalignment, known as a squint, as one eye tries harder to stay focused.