What Is Astigmatism?

In astigmatism, the eye focuses images on more than one point rather than the single point of normal vision.
An eye astigmatism can be accompanied by farsightedness, making it difficult for them to focus on close objects.
Optometrist can examine a patient's eyes for signs of astigmatism.
Astigmatism can cause blurred vision.
Glasses are often prescribed to correct astigmatism.
A person with astigmatism has an abnormally curved cornea.
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  • Originally Written By: Paulla Estes
  • Revised By: Tara Barnett
  • Edited By: Niki Foster
  • Last Modified Date: 22 July 2014
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Astigmatism is a condition of the eye which causes either blurred vision or a sense that each eye is seeing objects slightly differently. A structural problem — usually from either an unevenly curved cornea or lens — causes light coming into the eye to not focus correctly. This disorder is quite common, affecting about 30% of people to some degree. Treatment is not always needed, but when the problem is severe, prescription lenses or surgery can help improve the person's vision.

Anatomy

The human eye is usually a perfectly round sphere. Light that comes into the eye is focused by the cornea and the lens onto a point on the retina, where the image is detected and communicated to the brain. In someone with astigmatism, the cornea or the lens is not perfectly round; often it's shaped more like a football. When the eye is not curved properly, the light that comes into the eye cannot be focused on one single point, causing the image to be blurry.

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Astigmatism is a type of refractive error, meaning that the eye does not bend light coming into it to focus on the correct place on the retina. Nearsightedness (myopia) and farsightedness (hyperopia) are also refractive errors, caused by the cornea being too curved or too flat, respectively. The eyes of people who are nearsighted focus the image in front of the retina, while in those who are farsighted focus behind it. People can have both an astigmatism and another refractive error; it is estimated that about 2/3 of people who are nearsighted have the other condition as well.

Types

There are different types of astigmatism, depending on which part of the eye is irregularly shaped, where the light is focused, and whether or not the principal meridians of the eye are perpendicular. This condition can be caused by an defect in either the cornea or the lens, although the corneal type is more common.

A normal eye focuses an image on a single point; optometrists draw an imaginary plus-sign (+) at the center of the pupil where this focus point should be. These are referred to as the vertical and horizontal or principal meridians. In someone with astigmatism, the two meridians do not focus at the same point. If one focuses on the retina while the other does not, it's known as simple, while if both focus either in front or behind the retina, it's known as compound. One point in front and one behind is called mixed.

As with nearsightedness and farsightedness, the focus in front of the retina is called myopic and behind is hyperopic. Therefore, if one meridian focuses in front of the retina while the other is on it, it would be called simple myopic astigmatism.

When the principal meridians line up perpendicularly — meaning that they meet at a 90° angle — it is known as "regular" astigmatism. If the angle is off, it's called "irregular," and is a bit more difficult to treat. The irregular type is often caused by an injury to the eye or a disease called keratoconus, in which the cornea takes on a cone-like shape.

Symptoms

Minor astigmatisms often go largely unnoticed, but severe cases may cause headaches, squinting, and tired eyes in addition to blurry vision. Most people with cornea irregularities are born with them, but may not notice any problem until they get older. Even those who have few symptoms can be diagnosed with this condition in the course of a routine eye exam. Since many of the signs are not obviously or directly related to vision, people may find that treatment improves headaches they were not even really aware of.

Detection

There are several ophthalmological tests to determine the presence and level of astigmatism. A keratometer and a corneal topographer are instruments that can be used measure the curvature of the cornea. An autorefractor can give an estimate of the eye's ability to focus light properly. These instruments are non-invasive and most ophthalmologists and optometrists are able to detect even slight curvature problems during a simple eye exam.

Sometimes astigmatism can be detected at home by covering one eye to look at an object, and then changing to cover the other eye. By switching back and forth while looking at a single object or in one direction, the person may notice that the object seems to move, as though each eye is seeing it in a slightly different location. This usually indicates the presence of corneal curvature.

Treatment

Glasses or contact lenses can be prescribed to treat most forms of astigmatism, but they generally do not correct the condition. Often, two different lenses will help the eyes focus together, thus offsetting the uneven focusing. Eyeglasses cannot be used to treat people with the irregular form, although certain types of contact lenses typically can help. One type of contact lens actually helps to reshape the eye; this treatment is called orthokeratology or Ortho-K.

Surgical correction is an option for severe cases. A number of different procedures can be used to reshape the cornea of the eye and make it more spherical. Laser in situ keratomileusis (LASIK) surgery uses a laser to sculpt the underside of the cornea after the top part is lifted up. Photorefractive keratectomy (PRK) and a similar technique called laser-assisted subepithelial keratomileusis (LASEK) remove or fold back the very outer layer of the cornea and reshape the top surface. An optometrist can help a patient decide which method is a better option if surgery is recommended.

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Discuss this Article

NhanNg
Post 40

I have many friends who cure shortsightedness completely and naturally with "Clear The Vision". One of my friends used to be nearly blind, but now he can see everything clearer than ever before. I have read about this online. It's safe and It has a good guarantee. You have nothing to lose. Just have a look! Good luck.

anon225902
Post 39

I was amazed to find out Astigmatism can be induced by bad posture. Whilst it is always good to find out as much as you can about things, if you are anxious or concerned a little perspective is required. Lots of 'diagnosed' or 'suffering' comments are being posted. The reality is, in most cases people will just not even notice it, but when their optician uses a long and fairly unusual word, people fly into some sort of panic. Comments about curing this as the person doesn't want to keep going to the optician for the rest of their life is like saying I won't eat again so my teeth stay healthy and therefore I'll never need to go to the dentist!

An eye test is primarily a health check and as conditions affecting the eye are often painless and symptomless, routine (or otherwise) checks are essential whether you're long sighted, short sighted, have astigmatism or you didn't need specs at your last exam. Prevention is better than cure as they say. The timeline i believe with eyes is roughly this: (I've been told. feel free to contradict).

We're all very long sighted in the womb and when we are first born. Some of us lose all of this, some of us lose some of this.

In the early teenage years - I've noted a lot of comments from this age group - we can often have what is called a Myopic shift (or at any age). Meaning we can become more short sighted. This doesn't mean if you're long sighted, you become suddenly short sighted, just less long sighted or in the case of short sighted folk more short sighted. A range of factors can cause this, but it is believed to be thought that as school course work intensifies around this age i.e., more reading and close work - or these days staring at mobile phones! - this could be a major factor in causing this.

Early to mid forties: Things close up are harder or impossible to focus on or read requiring you to hold things further away to focus (until your arms aren't long enough anymore)!.This is called Presbyopia. It's a natural part of the aging process whereby the eye loses its ability to focus on things close up and which I believe is pretty much coming to all of us. This is the case whether or not you have required specs up to that point in your life. Your distance vision may still be totally spot on but you'll still need something for reading.

60's and upwards: Various eye conditions such as Glaucoma and Age Related Macular Degeneration (A.M.D) can become much more prevalent. However what you do now may have an effect on how, when or if these conditions manifest themselves later in life, by diet, lifestyle and eye protection (e.g protecting your eyes as best as possible from U.V exposure). Although some people will be predisposed to certain conditions through hereditary conditions.

Remember: 'Prevention is better than cure.'

The eye is a complex thing and even environmental, cultural and geography can play a part. Such as the vast majority of specs wearers in the Far East are short sighted. People of Afro-Caribbean descent are more predisposed to certain eye conditions such as Glaucoma. Eskimos apparently had no short sightedness until they were introduced to reading books!

anon192586
Post 38

I also have astigmatism. A few years ago I got a pair of glasses I wore for a year and never got used to. When I went to a different doc she said my prescription had not changed. I told her I could see better in my previous glasses because when I turned my head everything looked weird and it took a few seconds to focus.

To make a long story short, it was the material the lens was made of. The ones I had trouble with were poly-carbon and the old ones were just plastic. So I switched back to plastic and now can see just fine with my glasses. Might want to ask about that.

anon189404
Post 37

Does the astigmatism get worse if i wear glasses or contact lenses continuously?

anon176135
Post 36

I have had very severe astigmatism all my life and have been wearing glasses since I was about 8 years old. I am severely astigmatic which means I am about doubly astigmatic than most people and surgery is not an option. The good news is that because I have been wearing glasses since I was 8, I have trained my eyes to see better than people who don't wear glasses at all. I can read the bottom line on a chart with glasses. I am told that this is possible because my brain has trained my eyes to see well while my body was growing until I was 18 years old.

So for those of you who are still growing, wear your glasses always (the correct ones of course for your eyes) and you will see well. Glasses are really annoying and not much fun, but where would you be without your eyesight? Astigmatism is much better to deal with than lots of other problems in life!

anon171044
Post 35

I'm 12 and I've been wearing glasses for eight years, ever since i was four. i asked my eye doctor how long i would need glasses for, and she said for the foreseeable future. (this was in august) only now she tells me i have astigmatism. I was so mad at her. i hate wearing glasses. so should i get contacts? post your comments and give an opinion please. By the way, she has never told me i had astigmatism until recently.

anon153135
Post 33

I was told two years ago that I didn't need glasses because my eye vision improved, but I'm 12 now and they said you need glasses now. So I picked some and they said try them out one hour at a time.

So I did but the writing went blurry and everything looked like an illusion. Has anyone experienced that feeling? I have.

So they said I need special contacts because I couldn't get used to my glasses. But do I have this astigmatism? They told me I was short sighted in one eye and long-sighted in the other eye, so do I not?

anon153132
Post 32

My name is Amelia, and I wore glasses ever since I was a litle kid. Then something weird happened. Right, so I go in for an eye-test (I'm 12 now - this happened when I was about 10) and it's the usual can-you-see-the-letters test, yeah? At the end, my Op told me the great news: I didn't need glasses anymore! However, two years onward, this happened about two or three weeks ago.

By the way, I went for a check-up and they said I needed to wear glasses again. So they gave me some and told me to try them out an hour at a time.

But, you see, the weird thing is, my eyes went blurry when I put them on!

So I went back and told them my vision went weird and blurry when I tried to read (true) so I couldn't keep them on for long. They were a bit disappointed, and I had to have another eye test. Nothing was wrong with the glasses, apparently.

So, you're probably wondering, what happens now? Right, so they sat down and talked for a bit, and they broke the news to me that I needed "special" contacts. Special, how?

Good news: No glasses.

Bad news: they cost £22.50 a month!

Thanks. This means a lot to say this.

anon121612
Post 31

I'm 11 and I have high prescriptions (left eye 2.00 and right eye 1.25) both of my parents are over 4.00. doesn't everyone have astigmatism, if it's really something about the eye shape itself.

anon120005
Post 30

In college eons ago, I took an archery class. Not only would I not hit the bull's eye, but I would also miss the entire target. That's bad especially for innocent passers-by.

The instructor had me do the switching back and forth covering each eye alternately test. Then she asked to to look at the target with both eyes and determine which image the both eyes uncovered most resembled, the right eye uncovered or the left eye uncovered. I hope that makes sense.

Then, instead of pronouncing an astigmatism, she said that the image in which the one eye uncovered matched the both eyes open indicated my dominant eye. In this case it was my left eye, but, I am also right handed. She said I would have to shoot my arrows either with both eyes open or learn to use my left eye with either a left or right handed technique. I can't recall which was better for me. I made a C in that class and gave up all sports that required keen aim.

anon116689
Post 29

hi, just got informed that i have astigmatism and i am far sighted, but i knew i was farsighted. Anyway, it seems you can have astigmatism in one eye, but when you wear glasses, there is no problem, but i just got fitted for contacts, so i have to wear two different ones. also, i have extreme astigmatism, and i never knew that i saw different from anyone with glasses. i need some tips to help strengthen my eyes.

anon111180
Post 28

About switching back and forth between covering each eye, I had no idea this wasn't normal vision. Since I was a child I used to amuse myself with this little optical "trick" -- or until now I assumed it was an optical trick common to all of us.

My new eye doctor just diagnosed me the other day when I went to get contacts and he told me I needed special contacts for my astigmatism; I didn't even know what that was and asked if I really had astigmatism and he just said, yes, and it's fairly pronounced. I wonder if having basically spent a lifetime with it almost made it more difficult for bystanders to detect? Because again, I always just took this to be perfectly normal.

anon110384
Post 27

Astigmatism is caused by incorrect posture. Our eyes have been trained to maintain our balance and are always scanning for the horizon or any indication that you are indeed standing vertically.

When our posture is bad and we tilt our heads, the muscles around our eye have to pull unevenly to keep the eye in its place. This can cause the cornea to warp and become distorted. If you don't have astigmatism, keep your head straight and have good posture. If you do have astigmatism and know that you tilt your head, tilt your head in the opposite direction for about 15 minutes every two hours. This should correct the problem in one to two months.

anon103629
Post 26

Hi, I have had severe astigmatism since I gotten my first pair of glasses, and I also have a high prescription (+8.00 & +8.25 in left eye, +7.00 & +7.25 in right eye). I am almost 19 and I wear bifocals. I have recently had problems with seeing bright flashes of light, and light spots in both eyes (that always appear in the same place), and I was wondering if that was due to my astigmatism or if it could be happening because of some other eye disease.

No matter what, whenever I get a new pair of glasses my vision always seems blurred, and it seems as if my vision is getting worse all at once.

anon103320
Post 25

I hadn't been tested since i was 13. I'm now 19 and went for an eye test today, apparently in my right eye I'm short sighted and long sighted because of astigmatism and in my left eye i have mild astigmatism. is this possible? and the moving objects thing, i never bloody noticed until today! it's amazing how much you don't realize as a child!

milenaana12
Post 24

I was diagnosed with moderate Astigmatism when I had my eye test quite recently. I decided to opt for contact lenses, and my focus has improved enormously.

anon93398
Post 22

I have astigmatism apparently, but I think it's mild. I'm forced to wear the special contacts but they are so expensive! I'm only 18 and paying for my own college and I can't afford to pay so much. And I'm not going to wear glasses.

anon93372
Post 21

having recently been diagnosed with astigmatism, I wonder if this is why I cannot cope with quick images on computer games or with someone scrolling up/down a computer screen quickly. Could this be why? I also cannot bear bright lights.

anon88592
Post 20

i am suffering from astigmatism and i have been wearing glasses for quite a long time, but i still can't see perfectly, even with glasses. Although they have helped me reduce my blurred vision to some extent, the vision is not perfect. can anyone tell me is it normal or not, because i am tired of getting my eyes checked.

anon84989
Post 18

i just went to the eye doctor today. I have not been to one in ten years. i was wearing color contacts i bought at a store. now they messed up my eyes, and now i have astigmatism in both eyes.

anon75812
Post 17

I was diagnosed with astigmatism today. It's very mild but when I take off the glasses, the difference is phenomenal! Everything is blurry without them. No wonder my eyes were tired all the time and I was having headaches!

anon60211
Post 16

I am a teacher and am often glancing over students' shoulders as they write or take notes or a test. I can't read anything they have on their papers and they get very frustrated when I often stop them and ask to see their papers.

When I drive at night I am petrified! The headlights coming at me seem to be everywhere and blinding me. I have not driven at night since I was 28 years old.

I am 31 and was told I had astigmatism in both eyes it was moderate but since it was the first time I had been to the eye doctor and had never worn glasses they gave me a lesser prescription than I really needed.

They give me a headache and I hate wearing them. I have a student who also hates his glasses and won't wear them so I now wear them during his class.

I will suffer for him!

anon60197
Post 15

i have astigmatism and i wear glasses. i hope they can cure it before it gets worse.

anon58235
Post 14

I was required to wear eyeglasses when I was 10 because I've been having bad headaches and the doc said I have astigmatism. But I don't wear glasses anymore right now.

I am just wondering if this is a sign of astigmatism like I can control my eyesight to get blurry and make it very bad and then back to normal but it doesn't hurt my eyes.

I learned to do this since childhood till now. I have told my parents about this but they can't relate and forgot to ask about this to my past doctors. Or is it just normal?

anon55931
Post 13

i discovered i had astigmatism just a few years ago (i am 31 now). it is in my right eye and moderate. i wear a special contact in my one eye, but my vision often seems "misaligned" (other times, it is not really a bother)because one eye seems to overpower the other.

i haven't had serious problems, but I'm beginning to seriously consider LASIK surgery, as i anticipate the problem getting worse. my advice to anyone with vision problems is make sure you see a qualified ophthalmologist, they will help you diagnose your problem accurately.

anon55220
Post 12

I suspected that i might have astigmatism when I started to read a financial statement and thought that the lines where misaligned.

So I drew two lines with a ruler with a half inch gap in between and stared at them. To me, the lines looked like they were misaligned. I showed it to my roommate and he didn't see a problem. The eye doctors never caught it when I was a kid. Too bad, I could have been a star athlete but my hand-eye coordination was always off. Now I know why.

anon48054
Post 11

I have a reading glass which was issued me by an opthamologist couple of years ago. Now I have been diagnosed of astigmatism. Please where are my eyes heading to? I want to know. Can I cope with two eye glasses for the two defects? My head aches, my vision is blurred and I cannot grasp an object easily. Thank you for this medium.

anon41652
Post 10

I thought it was normal to see things jump when you close one eye at a time.I used to have this magic book that said that if you could do that, it was a trick to show all your friends or something. but now i have a bit of astigmatism! Stupid magic book.

anon41370
Post 9

I have just been diagnosed with mild astigmatism and found this page so helpful - thanks! My last optometrist was really rude to me when i said that sometimes i can't read things close up or from a distance. She obviously hadn't picked up on the fact that i don't have problems with eye sight, just fine details! Was so relieved when i got a second opinion - proof i wasn't going nuts! My left eye is 'zoomed out' while my right eye is 'zoomed in' and i have since noticed that i tilt my head a lot, and i have read that people with this condition can see walls tilting - does anyone else notice this?

anon40298
Post 8

i have mild astigmatism, and i have a pair of glasses, one lens "normal", the other slightly different.

anon37175
Post 7

I didn't know what astigmatism was or what caused it. I only knew it was blurry vision & headaches. You mention that with the years it increases with age. I was told I have astigmatism at the age of 15 now and 26. My optometrist told me that it will not advance. Is it true? Or as I get older my vision will be very poor? Thanks Nay

anon36922
Post 6

im using air optix contact lenses and these dont seem to treat it. are there special contacts that will help to treat it?

anon34077
Post 5

Thanks heaps for this page. I have very poor vision (short sighted) so I've been wearing glasses for a few years now, and even though my optometrist told me I have astigmatism on top of that, I've never been too sure what astigmatism was apart from blurry vision.

My astigmatism has worsened, but I've only been short sighted until I was about 13, so this explains why I have memories from when I was only six of objects jumping from different positions when I covered one eye (something which I thought happened to everyone) but my parents could never relate. It also explains why now I've noticed a considerable difference in colours from either of my eyes - I never knew these were symptoms.

Thanks again, I'll be sure to browse your site at my next chance.

-Mary

anon33556
Post 4

Yes lolamom that is a symptom of it. Astigmatism increase with age and if untreated they get worse.

anon22630
Post 3

actually, i astigmatism in my left eye and i can use acuvue2 lenses that only cost 22usd a box. that is for me a 6 month supply.

lucychandler
Post 2

Hi there,

I have an astigmatism in my left eye, and I have a very slight colour change in either eye, its unnoticeable unless I really concentrate on the colour of something and cover each eye individually, etc. My point is, I think astigmatisms can affect the eyes in many ways, not just blurry vision, but colour change, and as you say, focusing and zoom problems. I'd ask your optician about it if I were you. You'd need a high prescription for astigmatism so its really important you get it checked out, as not having the correct prescription can damage your eyes and make them worse. Some people use contact lenses as this gives them better vision than glasses, but I warn you now, if it is an astigmatism, you'll get Toric contact lenses, which are considerably more expensive than normal lenses. I'm paying £240 a year, and I only get 2 pairs of contacts a year (£50 to replace ONE lens if i lose it). Thats not including the £100 I paid for my specs!

goodness eye care is an expensive thing!

Anyway, hope this helps! :D

lolamom
Post 1

can a symptom of astigmatism be when you cover one eye the object looks zoomed in on and when you cover the other eye the object looks like you zoomed out so with one eye covered the picture looked really big and when i covered the other eye the picture was smaller. I am wondering because I have glasses and the doc. said my eyes needed strengthened and they don't help at all i have very blurry vision and it's cause it takes me awhile to focus on stuff can you give me an opinion please?

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