What is astigmatism? Astigmatism is when the eye’s front surface and/or lens are unevenly curved. Instead of sharply focusing light into one spot in the eye, the different curves stretch the light out, creating blurry or “stretched” vision. This affects sight at all working distances, unlike short- or far-sightedness. Can astigmatism be corrected? Yes. There […]
Astigmatism is when the eye’s front surface and/or lens are unevenly curved. Instead of sharply focusing light into one spot in the eye, the different curves stretch the light out, creating blurry or “stretched” vision. This affects sight at all working distances, unlike short- or far-sightedness.
Yes. There are many options to correct astigmatism: glasses, soft contact lenses, rigid contact lenses, and surgery. Book a comprehensive eye exam with IC Optometrist to discuss the most suitable option for you and your circumstances.
Science is still trying to answer this question for certain, but the story so far points the finger at:
There are several diseases which can create or alter astigmatism, so regular eye exams are crucial in diagnosing and mitigating these risk factors.
Uncorrected astigmatism causes several symptoms:
There are no immediate life-threatening associations with astigmatism, but there are indirect impacts to health and wellbeing. Studies show people with uncorrected astigmatism experience worse clarity, difficulties with grooming, trouble with computer work, struggling to drive at night, greater risk of falls, and a worse overall wellbeing.
It depends on the strength of your prescription and your state’s fitness to drive standards. For healthy people whose only problem is astigmatism, wearing glasses or contact lenses will almost always allow you to drive. If there are other diseases or factors, your optometrist may need to fill in a report to allow you to drive with conditions such as daylight-only hours or a radius restriction.
In simple cases, surgical procedures like LASIK can reshape the front surface of the eye to minimise or eliminate astigmatism. For people with underlying conditions which make the eye irregular (such as keratoconus), these procedures may worsen the situation. Instead, it may be appropriate to do “corneal cross linking” to help stabilise the eye shape and slow progressive worsening.
Want to know more? Keep reading below for all the answers.
Let’s remove “The Stigma” from astigmatism!
Have you noticed streaks and starbursts around lights while driving? Are you squinting and straining to make out that fine print? Maybe you’re even tilting your head to clear up some letters? These symptoms could mean you have astigmatism.
Astigmatism describes a distorted view of the world, where light that reaches our eye gets stretched out between two positions instead of coming to a single sharp point. You may have heard friends or family mistakenly refer to this concept as “a stigma”. The word astigmatism comes to English via Latin from Greek: “a-” meaning “without”, and “-stigmatos” meaning “a mark, spot, or puncture”. In other words, your eye is missing a sharp point of focus!
Astigmatism is very common, being found in approximately 40% of the global population, though it does vary between countries. It could be in one or both eyes, and can change with age. At IC Optometrist, our exams can easily diagnose and correct astigmatism with a range of optical solutions.
So how does this phenomenon happen? To begin, let’s take a look at the anatomy of the eye. The clear dome that covers the coloured ring is called the cornea. It is the first eye structure that light interacts with as it reaches us, and it is therefore responsible for the bulk of focusing that needs to happen for clear vision.
Some people’s corneas are evenly shaped, no matter what angle the curve is measured from. You can think of these people as having basketball-shaped eyes. However, other corneas will have one angle that is more curved than another. These people have rugby ball-shaped eyes. Or egg-shaped if you prefer your food metaphors.
For those with basketball corneas (without astigmatism), light reaches their eyes and is evenly bent to come to one single point inside the eye. This means that everything they look at from far away is equally clear, or equally blurry if they are shortsighted.
For those with rugby ball corneas (with astigmatism), light gets unevenly bent because of the different curves, leaving the light “stretched out” between two different spots inside the eye. This means that whatever they look at from far away, some angles may be clearer than others. For example, look at the diagram below which compares clear vision with various different angles of astigmatism.
Adapted from “The visual and functional impacts of astigmatism and its clinical management” (2014)
Obviously, looking at the world with this view is very uncomfortable! As a result, people with uncorrected astigmatism will typically experience not just blur and distortion, but more physical symptoms as well. The lack of clarity forces straining and peering behaviours, as well as squinting to try to make sense of a scene. Consequently, headaches that progressively worsen throughout the day are common. At night, there may be additional distortions to light sources, such as starbursts, haloes, and streaks.
There are multiple reasons why someone might develop astigmatism. There is a known genetic link, so if one or both of your parents have it, you are more likely to inherit astigmatism. We know that it can develop and alter as we age, which is likely the result of increased pressure on the cornea from the eyelids. Astigmatism can be created or worsened by excessive eye rubbing, especially in cases of allergies.
There are also some eye conditions which create extreme and unpredictable astigmatism, such as Keratoconus. This disorder changes the shape of the cornea to be more cone-like and uneven. These anatomical changes create what is known as “irregular astigmatism”. In these cases, the optics of the eye become significantly more complex and require more sophisticated solutions.
For most people, their football-shaped corneas fit into the category of “regular astigmatism”, which is readily correctible. Spectacles and contact lenses are designed with different powers at 90° from one another to cancel out the mismatched curves of the cornea. With correction in place, most people will achieve at least 20/20 vision (or the Australian metric equivalent, 6/6) in the absence of any disease.
At IC Optometrist, we maximise your correctable vision utilising state of the art equipment. The DNEye scanner by Rodenstock uses 7 000 data points per eye to make a digital model of your specific anatomical measurements. This gets combined with your prescription to create bespoke Biometric Intelligent Glasses (B.I.G. Exact lenses) that deliver the clearest vision possible. This translates to reduced glare and haloes around twilight, and more efficient detailed near work.
Irregular astigmatism correction can be done with glasses or soft contact lenses but usually achieves a limited improvement depending on the complexity of the case. These people typically benefit most from the use of a tailor-made rigid contact lens. Such contacts cover the irregular cornea beneath and create a smooth, regular front surface for light to interact with. Almost like a second cornea!
In some cases, surgery may be the preferred option for both regular and irregular astigmatism patients. For the more symmetrical corneas, LASIK is a procedure that can reduce or eliminate astigmatism by strategically thinning the cornea. For those with keratoconus and other conditions, such a procedure may worsen their vision or health, so an alternative to stabilise the structure may be more appropriate. For example, those with keratoconus will sometimes undergo “corneal cross linking” to help minimise further progression.
If you think you may have astigmatism, or are just wanting professional advice on appropriate solutions for your eyes, book in to see the team at IC Optometrist. Our comprehensive exams will deliver your best corrected vision, as well as screen for any ocular diseases or disorders. Don’t put up with blurry vision any longer. Experience the difference a tailored consultation and optical solution can make to your life.
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