What is Astigmatism?
You’ve heard of people being short-sighted or long-sighted, but what about when someone has blurry vision at all distances? This type of refractive error is known as astigmatism and in Australia 1.4 million have this eye condition.
Astigmatism is a common eye condition in which you have difficulty seeing clearly at both near and far distances. People who are long-sighted (hyperopia) or short-sighted (myopia) often also have astigmatism, or astigmatism can occur by itself. People who have astigmatism can experience eyestrain and headaches, and may feel tired at the end of the day.
Astigmatism isn’t dangerous, it is not a disease – it simply means that the front surface of a person’s eye (the cornea) has a curvature shaped more like a rugby ball than a soccer ball. Light enters the eye through the cornea and bends (refracts) to focus on the light-sensitive tissue at the back of the eye (the retina). From there, a signal is sent to the brain, which then processes the image that we see. Normally the cornea’s curvature allows light entering the eye to focus at one point on the retina and this creates a clear, crisp image. When the cornea is shaped more like a rugby ball, light entering the eye focuses at two places on the retina and this leads to blurred vision.
Causes of Astigmatism
Astigmatism occurs due to the cornea or lens, the parts of the eye that are responsible for focusing light, having a different curvature in one direction compared to the other. If the curve of the cornea or lens is not perfectly round but is shaped more like a football, astigmatism will result and the eye will not be able to focus light accurately onto the retina. This is called a refractive error.
There is no set time when astigmatism may present itself. For some people, they are born with it, for others it can develop throughout their life.
There are two types of astigmatism:
- regular — where the cornea is curved more in one direction (say vertically) than the other (say horizontally)
- irregular — where the curvature of the cornea is uneven across the surface of the eye
Both of which cause poor focus at all distances. If the world looks blurred to you, or if you have difficulty seeing at night, headaches and other symptoms that generally cause you to squint you may have astigmatism and we encourage you to make an appointment to see an optometrist today. You can find an optometrist near where you live by using our Find an optometrist search function.
Symptoms of Astigmatism
The main symptom of astigmatism is blurry vision at all distances and it’s quite common to also experience eye strain and/or headaches. Most people with astigmatism have it from a young age, but it’s not uncommon to develop astigmatism later in life. Have your eyes assessed by an optometrist if you notice any of these symptoms.
People with astigmatism may think they see clearly when looking at objects and may not realise they need glasses. It is often eyestrain and headaches that are the first symptoms.
It is important to have an eye examination by an optometrist who will be able to test how well you see by placing different lenses in front of your eyes. Using this information and other tests, the optometrist can tell if you have astigmatism and prescribe lenses that give you the clearest and most comfortable vision.
Astigmatism can be diagnosed following a series of tests performed by your optometrist. To determine the clarity of your vision, you’ll be asked to read letters from a chart (known as a visual acuity test). Next, you’ll look through a series of lenses to determine the focusing power of your eyes. Your optometrist may also use a piece of equipment called a keratometer or topographer to measure the curvature of the front surface of your cornea.
Almost everyone will have some degree of astigmatism – it’s unlikely to have a perfectly smooth and round corneal surface – but for the majority of people, minor surface irregularities do not cause noticeable vision problems.
When astigmatism does lead to blurred vision, your optometrist will prescribe glasses or contact lenses to correct the refractive error and restore clear vision.
While prescription glasses are the primary choice of vision correction for astigmatism, contact lenses can also be used and are a great option for active adults and children. In the past contact lens options were limited for patients with astigmatism and some patients may have been advised that due to a high prescription they were unsuitable for contact lens wear. As material and manufacturing technology improves, there are now a huge range of contact lenses available for those with astigmatism – including soft 1-day disposable options.
For those with irregular astigmatism wearing specially designed rigid gas permeable contact lenses often provides clearer vision than can be obtained with spectacles.
Wearing glasses or contact lenses to correct astigmatism will not weaken your eyes.
A balanced and healthy diet is important for eye health just like general health, but eating lots of carrots is unlikely to stop astigmatism developing.
Properly prescribed glasses or contact lenses will make tasks much easier by improving how clearly you see and making it more comfortable for your eyes but astigmatism cannot be cured.
Your optometrist will tell you if you need to wear glasses full-time or part-time to help you see clearly. If you have mild astigmatism you may not need glasses at all. Otherwise, you may need glasses part- or full-time when reading books, using computers, driving, going to the cinema and performing other tasks that require you to see fine detail clearly.
Other Correction Options
Many people don’t realise there are vision correction procedures that can permanently correct astigmatism. However, not everyone is a good candidate for these procedures. It largely depends on how high or type of astigmatism you have, your lifestyle, health and age. Your optometrist will be able to discuss your suitability for the procedures listed below, and may refer you to an ophthalmologist (eye surgeon) for further opinion.
Laser Eye Surgery
Laser eye surgery permanently reshapes the corneal surface. To be eligible for laser eye surgery, you need to be aged between 18 and 55, have had a stable glasses prescription for at least 12 months, have good general eye health and not be pregnant or breastfeeding.
Intraocular lenses (IOLs)
Intraocular lenses (IOLs) are used to replace the eye’s natural lens during cataract surgery or refractive lens exchange. In addition to correcting presbyopia (age-related long-sightedness), premium IOLs can be designed to correct your astigmatism and give you clear vision at all distances, removing the need for glasses for reading or any other activities. This particular type of IOL is known as a toric lens. Individuals who have non-toric IOLs (and therefore still need glasses to correct their astigmatism) can have a secondary procedure such as laser eye surgery or have their IOL replaced with a premium lens to eliminate their need for glasses. IOLs are generally reserved for people aged over 50 because a younger person’s natural lens is superior to the currently available artificial lenses.
Optometrist Luke Arundel chats about contact lenses and discusses top tips for users to be aware of. Video credit: Optometry Australia
Astigmatism and Night Vision
At night or in low light conditions the pupil of the eye dilates to allow more light into the eye. If you have uncorrected astigmatism it is common to experience worse vision at night with halos, flare and glare commonly reported.
Tips for drivers
Get your vision corrected
Getting your vision corrected is important since most critical decisions made by drivers are based on sight. A lot of drivers aren’t aware of the relationship between good vision and good driving, especially if you drive at night. Figure out what works best for you. If you get glasses and toric contact lenses, you should first get used to them when you’re not driving.
Wear anti-reflective glasses
If you wear glasses, an anti-reflective coating on your glasses may help reduce glare and distracting reflections.
Where Do I Go For More Advice?
We recommend making an appointment with an optometrist for a comprehensive eye examination. Comprehensive eye examinations, at regular intervals starting from childhood, ensure that most eye conditions can be prevented or corrected. Eye examinations can also be an important tool for determining your overall health.
Use our Find an optometrist search function if you do not have an optometrist, or would like to find an optometrist close to where you live.
Commonly Asked Astigmatism Questions
What causes astigmatism?
Astigmatism occurs due to the cornea or lens, the parts of the eye that are responsible for focusing light, having a different curvature in one direction compared to the other. If the curve of the cornea or lens is not perfectly round but is shaped more like a football, astigmatism will result and the eye will not be able to focus light accurately onto the retina (sensory layer at the back of the eye).
Can astigmatism be cured?
Properly prescribed glasses or contact lenses will make tasks much easier by improving how clearly you see and making it more comfortable for your eyes, but astigmatism cannot be cured and is often hereditary.
How can I tell if I have astigmatism and how will it affect me?
People with astigmatism may see clearly when looking at objects and may not realise they need glasses. It is common for people with astigmatism to have difficulty seeing clearly at all distances and they may develop eyestrain and headaches.
It’s important to have an eye examination with your optometrist who will be able to test how well you see by placing different lenses in front of your eyes, so he or she can then tell if you have astigmatism and prescribe the lenses that give you the clearest and most comfortable vision.
Glasses and contact lenses are good options for correcting astigmatism.
Published date: 27 July 2016 Reviewed date: 14 February 2020
Author: Luke Arundel, BAppSci (OPtom) Hons, FIACLE, FCCLSA, FBLSA, FBCLS, AdjAssProf University of Missouri St Louis, GCOT, CASA CO
Bio: Luke Arundel is Chief Clinical Officer of Optometry Australia. He graduated with Honours in Optometry from Queensland University of Technology in 1998 and has worked extensively in Australia and Ireland. He currently holds fellowships with the BCLA, CCLSA and IACLE and became an Adj.Ass Prof. of the University of Missouri, St Louis, USA in 2008. His professional interests include keratoconus, post-graft and scleral lens fitting, dry eye, ortho-k and paediatric contact lenses. He has worked in specialty contact lens practices in Brisbane and Melbourne and in the contact lens manufacturing field along with time in the public health and education sectors. Luke’s role at Optometry Australia sees him provide professional services assistance to members in audits, investigations and medico-legal matters along with leading development of resources and special projects.
Disclaimer: No information provided on the Good vision for life website is intended to constitute or substitute advice from visiting an optometrist. Many factors unknown to us may affect the applicability of any information on this website. You should seek appropriate personalised advice from a qualified optometrist about any eye health and vision conditions.