Astigmatism

“Two Focal Points”

If the corneal surface were perfectly round like a marble or a ball-bearing, then all of the light rays that constitute an image would pass through cornea equally and come into focus on a single spot of the retina. However, human body parts are not “perfect” and the corneal surface is never perfectly round. This deviation from perfect roundness is microscopic, but it is enough so that light rays passing through one area in the cornea are focused differently from light rays that pass through other areas. When one image is focused into two spots, this is called astigmatism. If the corneal surface were perfectly round like a marble or a ball-bearing, then all of the light rays that constitute an image would pass through cornea equally and come into focus on a single spot of the retina. However, human body parts are not “perfect” and the corneal surface is never perfectly round. This deviation from perfect roundness is microscopic, but it is enough so that light rays passing through one area in the cornea are focused differently from light rays that pass through other areas. When one image is focused into two spots, this is called astigmatism.

Most people have some degree of astigmatism – it is only a problem when the degree of astigmatism is enough to blur the vision. To correct astigmatism, both of the focal points need to be put into a single focal point on the retina. To achieve this, an artificial lens is placed in front of the eye (glasses or a contact lens) to shift the two images onto the same single spot of retina.


Answers to common myths about astigmatism

Oh no! This astigmo, sticky-mo, Aston-Martin, stigma… WHATEVER you call it is a serious disease!

Not at all. While astigmatism has a funny sounding name, it is no worse (or better) than having myopia (“near sighted”) or hyperopia (“far sighted”) or attached earlobes or unattached earlobes. The most accurate way to think of astigmatism is to imagine two spots of light – at least one (and maybe both) are missing their target. With glasses or contacts lenses (or, with LASIK) both spots of light are put into sharp focus exactly on target. Really, that’s the whole shebang! Having astigmatism is not nearly as serious as a case of the cooties, and it hurts less than a pizza burn.


If my child uses her glasses all the time, she become dependent on them

Sure, just as you are dependent on listening to conversation at a volume greater than a whisper. While you could listen to people whispering all day long, wouldn’t this be hard to do? Isn’t it wonderful that people speak up so they can be heard? People with astigmatism may be able to “get by” without their glasses, but it’s not easy – people with astigmatism appreciate how much better they can see once they get used to their glasses.


Using glasses will weaken the eyes

Nonsense! The eyes will not “wear out” from using glasses anymore than the sense of hearing “wears out” from listening to things at a normal volume all day. Imagine if your parents had told everybody around you only to whisper so that your hearing wouldn’t “get weak.” Bet you wouldn’t have liked that! Why would you deprive your child of the ability to see clearly? Does the sense of smell, touch, or taste wear out from being used constantly? Why would the eyes? Sometimes, not wearing astigmatic glasses can lead to vision loss (amblyopia).


If my child needs glasses, does this mean that he has “weak eyes?”

So long as the vision can be corrected to the normal range with glasses, then the eyes are not “weak.” When the structures of the eye are healthy and all that is needed is some help with putting things into focus, the eyes are considered healthy. Unfortunately, there are certain eye diseases where the vision can not be improved to normal with glasses (or contact lenses).


The glasses should be worn only to see the board

The glasses should be worn only to see the board. Without question, children with astigmatism who need glasses to see things clearly should wear their glasses in order to see the board at school – it would be a shame for your child to do poorly in school because she couldn’t see the lessons and assignments. However, if your child needs glasses to see well, why wouldn’t you want her to see well all of the time?


If my eyes are fine, then how did this happen?

Astigmatism is not anybody’s “fault.” But, if it makes you feel better, then you can always blame the other parent and their family (just kidding). Seriously, while there is some familial tendency for astigmatism, the genetics are not very clear-cut and astigmatism “just happens.”


My child should have her eyes examined every few months now

People with astigmatism should have a thorough eye exam once a year (or so) in order to make any adjustments in the glasses. If your child reports blurry vision before one year, however, then it may be necessary to make an adjustment in their prescription sooner. Sometimes astigmatism diminishes less over time – sometimes, children can “outgrow” the need for glasses. It is not possible to accurately predict who will “outgrow” their glasses.
   
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