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If you have astigmatism, you suffer from a type of refractive error. A refractive error refers to when your eye is unable to refract (or bend) light properly onto the retina.
In this case, astigmatism occurs when the curvature of the cornea or lens is not regular. The curvature may appear in the shape of a football or egg. Because of this incorrect formation of the eye, you can find viewing objects difficult.
In general, astigmatism is present at birth or can develop after an eye injury, surgery, or disease. If you have astigmatism, you may also have myopia (nearsightedness) or hyperopia (farsightedness). These conditions tend to co-exist.
Fortunately, treatment options, including refractive surgery, are available for astigmatism.
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In more severe cases of astigmatism, you may have symptoms that include:
Some people can confuse astigmatism with amblyopia (often referred to as a “lazy eye”). These eye conditions are not the same. However, severe astigmatism can contribute to amblyopia.
Astigmatisms happen when your cornea or lens has a steeper curvature in one direction or the other. There are two different types of astigmatism:
Eye doctors do not know why the curvature of the eye varies from one person to the next. However, the likelihood of astigmatism is higher in people with a family history of the condition.
It is important to remember that astigmatism does not occur because of:
Again, astigmatism is often present at birth. It can also develop after you have an eye injury, surgery, or disease.
This particular refractive error happens in approximately 1 in 3 people in the United States.
You may find that ophthalmologists and optometrists use various measurement approaches for astigmatism. Although the prescriptions may seem different, your optical shop should have no problem understanding what your eye specialist prescribed.
In general, though, your ophthalmologist or optometrist will measure astigmatisms in diopters. A perfect eye with no astigmatism will have 0 diopters. However, many people will have between 0.5 to 0.75 diopters of astigmatism.
When you have a measurement of 1.5 or more diopters, you most likely will need contacts, eyeglasses, or even corrective surgery to enjoy improved vision.
With eye prescriptions, there are two areas or numbers that refer to astigmatism:
People who are 60 years old and up have a higher chance of hyperopia (farsightedness) and/or astigmatism than younger people.
To test for astigmatism, you will undergo a comprehensive eye exam. In this check-up, your eye doctor will examine your visual acuity (your ability to discern the shapes and details of objects you see). You may be asked to read letters on an eye chart.
You may also undergo other exams with several different devices.
Your eye doctor may use the following tools during your eye exam:
Another option to help determine if you have astigmatism is online testing. Multiple online tests are available and can serve as an initial means to identifying a vision problem.
The tests are simple. You will look at a display of shapes and lines while standing a certain distance away from the monitor. You will have to cover your left and right eyes, alternating between both during this test.
While online tests are helpful, they are not conclusive. These tests rely on your judgement, and accuracy is not precise.
In other words, to have a confirmed diagnosis of astigmatism, you should follow up with an eye care professional. You will be able to undergo all the relevant tests and have results that shed light on your eye health.
Treatment for astigmatism may include:
Eyeglasses for people with astigmatism have a special cylindrical lens prescription. This means that specific parts of the lens boast additional power. In many cases, a single-vision lens may work to provide clear vision at any distance. Although, if you’re over the age of 40 and have presbyopia (poorer near vision due to aging), you may need a bifocal or progressive addition lens.
People with severe astigmatism may need to use rigid gas permeable lenses.
However, if you do not have severe astigmatism, you may be eligible for soft lenses called toric contact lenses.
It is essential to visit your optometry clinic and speak with a specialist to determine which eyewear option suits your needs.
An eye doctor may recommend this type of laser surgery to treat astigmatism. LASIK stands for laser in situ keratomileusis.
The LASIK procedure is a basic procedure that consists of the following steps:
If you have astigmatism and decide to undergo LASIK surgery, you can enjoy many of the advantages, including:
Improved vision for more extended periods. A primary concern about corrective eye surgery is duration. However, with LASIK surgery, you may be able to make the most of the stronger vision for long, if not permanent, periods. This means that you may be able to hold off on wearing eyeglasses or contacts to participate in regular activities.
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Boyd, K. (2021, February 23). What is astigmatism? Retrieved March 30, 2021, from https://www.aao.org/eye-health/diseases/what-is-astigmatism
Vimont, C. (2021, February 22). What do astigmatism measurements mean? Retrieved March 30, 2021, from https://www.aao.org/eye-health/diseases/what-do-astigmatism-measurements-mean
Vitale, Susan et al. “Prevalence of refractive error in the United States, 1999-2004.” Archives of ophthalmology (Chicago, Ill. : 1960) vol. 126,8 (2008): 1111-9. doi:10.1001/archopht.126.8.1111. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/420707#:~:text=We%20found%20that%20refractive%20error,and%20of%20astigmatism%2C%2036%25.