What is High Astigmatism?

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  • Written By: D. Poupon
  • Edited By: Jenn Walker
  • Last Modified Date: 26 July 2018
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High astigmatism is a severe form of astigmatism, a medical condition in which an irregularly shaped cornea or lens in the eye causes blurry vision. There are no hard and fast rules for categorizing astigmatism, but astigmatism of over four diopters is generally considered high. Glasses, contact lenses, and surgery are all potential treatments, depending on the severity of the astigmatism and the irregularity of the shape of the cornea.

People who have normal vision have perfectly round corneas, the transparent surfaces that cover the pupil of each eye, and lenses, which focus light. Many people have an irregularly shaped corneas or lenses in one or both eyes, which are elongated in some direction, like a balloon. This is called astigmatism, and the irregularity is measured in diopters. If the astigmatism is less than 0.6, then vision is still considered normal and does not need correction.

A high degree of astigmatism, of over four diopters, will cause significant vision problems. Straight lines may appear wavy, making driving a vehicle or operating machinery not only difficult, but dangerous. Having astigmatism is different from near or farsightedness because blurry vision occurs at all distances. Reading with a severe astigmatism will usually cause eyestrain, leading to frequent headaches.


Moderate and high astigmatism can usually be corrected. Many brands of toric lenses are available for diopters 0.75 to 2.25. Specialty lenses, such as one-day, colored, and multifocal lenses, may not be available at these strengths. As the degree of astigmatism gets higher, the choices of soft contact lenses become slimmer, and rigid contact lenses may become the only available choice. This is also true for people whose astigmatism does not occur on or near the vertical or horizontal axis.

For extremely high astigmatism, over five diopters, surgery may be a suitable option. Astigmatic keratotomy and laser-assisted in situ keratomileusis (LASIK) surgeries both attempt to permanently correct cornea abnormalities. Often high astigmatic patients will see improvement, but may still need to wear glasses or contact lenses to perfectly correct their vision. Other unlucky patients will need to have more surgery. New vision problems, such as trouble with night vision and sensitivity to light, may be side effects of corrective surgery.

Some sufferers may need to stick with glasses. People with small eyeballs may have difficulty finding comfortable contact lenses, while people with small irises are not good candidates for surgery. The astigmatism of people with keratoconus, or cone-shaped corneas, usually cannot be corrected by anything but glasses.


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Post 7

I often squint my eyes when I'm reading, then when I look normally at any writing, it looks blurry but I'm not nearsighted. And I am very sensitive to light. It hurts my eyes every time I go outdoors. When I'm reading books, I often experience eyestrain. I also sometimes get migraines. Is this astigmatism? I want to know.

Post 6

I am about to use contact lenses after a lifespan of 17 years without knowing I had astigmatism. My left eye isn't too bad (2.25), but I was shot with an airsoft gun at my right eye, so I went to the doctor and that is when my family and I realized I had such a bad sight. My right eye has 4.75 in astigmatism or however you say it. Over the past year, my right eye went from 4.25 to 4.75, but nothing to worry about.

Tips: If you know someone who sometimes struggles to read or concentrate, you should tell them to get their eyes checked. If you never had perfect sight, you wouldn't know if you have it or not.

Post 5

I have Astigmatism (0.75 in left eye, 1.75 in right eye) and I'm experiencing major problems both when reading at the computer or going outside. I have a hard time focusing no matter what I'm doing, can't drive and the glasses I have (I changed lenses three times this year to no effect) make me feel worse than if i don't use them.

I'm desperate and don't know what to do anymore. My doctors also told me I'm not a good candidate for surgery. I already spent a lot of money, buying the best possible lenses on the market (both glasses and contacts), went to see four different ophthalmologists. I just cannot understand why I'm experiencing such major problems with only a moderate astigmatism.

Post 4

@TreeMan - I believe when LASIK was first invented they could not use it for astigmatism, because they had not perfected the techniques yet. Now that it has been around for a while, I am pretty sure they can fix most vision problems with the laser. Like the article says, though, if you have extreme astigmatism, it is possible that the only way to fix the cornea would be with regular surgery. I think at that point, I would just deal with glasses for the rest of my life.

I don't think I could ever bring myself to do LASIK, though. Besides the LASIK eye surgery cost, I always seem to hear a lot of stories about people who have

gone through the process and had worse sight than when they started. Granted, some people say it works perfectly, but I don't trust it.

I think I would rather just go through the rest of my life wearing glasses and contacts. I kind of like wearing glasses sometimes, anyway. It's just an easy way to give yourself a new look.

Post 3

I was always under the impression that you could not get LASIK surgery if you had astigmatism. I am pretty sure that one of my friends was telling me that, because he wanted to have it done once.

He is still at the point where he can wear contact lenses for astigmatism, but I guess he would like to get to the point where he doesn't have to have glasses or contacts at all.

I have heard a lot about LASIK but don't really know what it is. What all is involved in the process as far as using the laser to correct the shape of the cornea? I have heard there are a lot of laser eye surgery risks. Is that true, or have most doctors been doing it long enough that it isn't really a problem anymore?

Post 2

@kentuckycat - In regards to the first question, you should be able to find the diopter on the box to your contacts. As far as whether or not contacts are always blurry with astigmatism, I am not completely sure. I also have astigmatism, but it isn't very bad. I think I am somewhere between a diopter of .6 and 1, and my contacts work fine. That being said, I can still read books and do a lot of things without glasses or contacts. It only starts to be a problem if I am trying to watch television or read things that are more than 5 feet or so away from me.

I know that for some people astigmatism can be

a big problem. I have a family member that I assume would be considered to have high astigmatism. She can't wear the toric contact lenses, and the lenses of her glasses have to be very thick. She can see all right once she has her glasses on, but she can't see things right in front of her without them.
Post 1

Besides just asking your eye doctor, is there any way that you can tell what your diopter is? I have astigmatism, but I don't think it would be considered high. I have worn contacts for most of my life, and they seem to work fine.

I don't know if it is the same for everyone with astigmatism, but I find that no matter what type of contacts I get, my sight is never quite perfect. There is still always a little bit of blurriness left over. I am farsighted in my other eye, and I can see perfectly with those contacts. I am never sure if it is just the astigmatism that makes fitting contacts difficult or if maybe my eye doctor just isn't able to get me the right prescription. Whenever I wear glasses, though, I can see just fine out of both eyes.

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