If you're experiencing blurry or distorted vision, especially when looking at objects from a distance or up close, you may have astigmatism.
Astigmatism is caused by an irregularly shaped cornea, which causes the light to focus unevenly on the retina. While astigmatism can be concerning, the good news is, it can often be easy to correct with the right treatment.
In this post, we will provide a detailed explanation of what astigmatism is, its causes, symptoms, and the treatment options available to help you better understand this condition and how to manage it.
About Astigmatism
Astigmatism is measured in Diopters (cylindrical diopters).
Astigmatism occurs quite often and sometimes even goes unnoticed. There was a large population study in the USA, Canada, and the UK that concluded that only 11% of all people have 0.00 diopters of astigmatism.
Data on the general population | Percentage |
People with astigmatism of −0.25 to −0.75D (Diopters) | 56.2% |
People with astigmatism in one eye that is worse than the other eye | 23.9% |
People with astigmatism, the difference between their eyes is less than −0.75D | 82.1% |
Astigmatism is likely to be symmetrical. If someone has an astigmatism of more than −1.00D in one eye, there is an 80.8% chance that their other eye will have it too.
Symptoms of Astigmatism
Here are some of the most frequent symptoms of astigmatism:
Blurred or distorted vision
Eye strain and discomfort
Headaches
Reduced night vision
Eye astigmatism can cause objects to appear blurry or out of focus, especially at night or in low-light conditions.
People with astigmatism may experience frequent eye strain and headaches. Especially when reading, working on a computer for longer periods, or engaging in other activities that require a lot of visual focus.
Some people may experience double vision or the perception of two images instead of one. In addition, eye astigmatism could make it difficult to focus on fine details or to see the small print clearly. That is why most people with this condition squint their eyes quite often.
Astigmatism is very obvious at night, especially when driving, as the pupil is dilated and it lets in more light to the retina. In that case, the refractive imperfections are more obvious and one notices 2 spikes of light in opposite directions coming from a direct light source like car lights, street lights, and traffic lights.
This is very well illustrated in the following video:
RELATED: Life with Astigmatism
Causes of Astigmatism
Our eyes have two structures with curved surfaces that bend (refract) light and allow us to see clearly:
Cornea - The clear structure in the front part of your eye, covered by the tear film
Lens - the transparent structure in the eye that can change shape to focus on near objects
In a perfectly shaped eye, each of these elements has a circular curvature similar to the surface of a smooth ball.
If those curves on the cornea or the lens are mismatched, then light rays fail to bend correctly, causing a refraction error (refractive error). All of this causes an unfocused image to form on the retina. So overall, astigmatism is a type of impaired refraction of light.
Blurred vision may appear more in one direction - horizontally, vertically, or diagonally.
Astigmatism is NOT a disease and is NOT caused does not get worse by reading in poor light, sitting too close to the TV, or squinting.
Astigmatism can also occur in combination with other refractive errors — nearsightedness (myopia) or farsightedness (hypermetropia).
The condition can be present from birth, or it can develop after an eye disease, eye injury, or surgery.
When do I have to see an eye doctor?
As we discussed in the beginning, many people have astigmatism. But this does not mean that correction with glasses is absolutely necessary.
We advise you to make an appointment with an eye doctor if your complaints interfere with your ability to perform daily activities (seeing blurry when working on your laptop, having frequent headaches, and eyestrain).
An eye doctor or optician will perform a special test called auto-refractometry, which will help to determine the optical error of your eye. The device works by shining a light beam and analyzing the returned light rays reflected by the back of your eye.
On the left image, we show a standard auto-refractometer (a device that measures the refractive error of your eye). On the right of the image, you see a printout. In this case, the printout demonstrates that the patient has +0.75 D (hyperopia or farsightedness) combined with -0.75 D astigmatism of the right eye, and +0.75 D (hyperopia or farsightedness), combined with -0.50 D astigmatism of the left eye.
You may notice that a minimum of 3 measurements per eye is performed and the final result is their average.
After the refractometry, patients undergo an examination called a refraction test where he puts different glasses with different power to correct it.
The examiner can determine if you have astigmatism or another refraction disorder (nearsightedness or farsightedness) and proceed to correct it if necessary. Keep in mind, small degrees of refractive error do not need to be corrected if you have no symptoms or complaints.
High degrees of astigmatism, as well as progressing astigmatism, or hard to correct with glasses may be caused by a condition called keratoconus. Keratoconus is a disease of the cornea and should be investigated further by your eye doctor.
What are the astigmatism treatment options?
After undergoing a complete examination, there are several treatment options for correcting astigmatism (and refractive error of the eye in general):
Correction with eyeglasses
Eyeglasses are the most common treatment for eye astigmatism.
The lenses that correct astigmatism have different powers in different meridians to compensate for the irregular shape of the cornea. Glasses are easy to keep clean and provide good-quality vision.
The negatives are limited field of vision, discomfort, and high costs.
Correction with contact lenses
Soft contact lenses can also be used to correct astigmatism. The lenses for astigmatism are called toric contact lenses.
Contacts are ideal for active people, those playing sports and having professions that require clear vision, or having certain eye conditions that cannot be corrected with glasses.
There are some negatives as well. For instance, a higher risk of infection, eye irritation, dry eye restricted activities like swimming and showering while wearing contact lenses, maintenance, and costs.
RELATED ARTICLE: Glasses or Contact Lenses: What is the best choice for you?
Orthokeratology
Orthokeratology or Ortho-K is a type of special rigid gas permeable contact lens. You put Ortho-K lenses in your eyes before you go to bed and wear them at night while you sleep. It temporarily reshapes the cornea curvature and improves vision during the day.
While it can be a great option for some patients, there are a lot of limitations and negatives in this treatment method as well.
Some of the disadvantages are high costs (most types of insurance do not cover Ortho-K contact lenses), limited effectiveness (meaning the effect carries on how many hours you sleep and wears off during the day), and last but not least - the risk of corneal infections, irritations, and dry eye.
Laser refractive surgery
Refractive surgery, also known as LASIK, SMILE, or PRK, also helps correct astigmatism. The procedure uses a special type of laser to reshape the cornea, thus improving vision. If you want to learn more about laser eye surgery, check out our article: Laser Correction Surgery.
Implantable lenses
Eye surgery with implantation of an implantable lens, called a phakic intraocular lens, can be performed to correct astigmatism. These lenses are implanted in front of or behind the iris and front of the eye's natural lens.
Which is the best option? Consult an eye specialist to determine which treatment is right for you, based on the degree of your astigmatism, your lifestyle, your eye health, and other factors.
Astigmatism in Children
Why is diagnosing and correcting astigmatism in children so important?
If not corrected in time, high astigmatism in children can lead to "lazy eye".
Unlike adults, children do not realize or complain that their vision is blurry. Uncorrected astigmatism can seriously affect a child's ability to recognize small details clearly and perform in school or in sports.
Imagine being a child who sees the world blurry. You just cannot know that there is a possibility to see things more clearly as you may have a refractive error in your eyes.
Luckily your parents read this article on and know when and why to take you to the prophylactic eye examinations, recommended for children.
We at Ophthalmology24 advise you to take your child for prophylactic eye examinations:
Immediately after birth
At 6 months old
At 3 years old
At 7 years old
During the school years (ages 7–18)
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Sources:
Astigmatism, Atanas Bogoev M.D. for Ochno Zdrave
✅ Medically reviewed
Checked by Atanas Bogoev, MD.