Prescribing Glasses for Children
Why are glasses sometime necessary to see better?
In order to see clearly, the front part of the eye (the cornea and lens) must focus a tiny image onto the back of the eye (the retina). If the image is not focused precisely, blur is the result. To help focus the image properly, we can use lenses in front of the eyes (glasses) or lenses on the surface on the eye (contact lens).
Myopia is when you cannot see distant or far-away objects clearly. It is also known as “near- sightedness” as the near/close images are clear. When the focusing system of the eye (lens and cornea) place distant objects in front of the retina, but not on the retina, this is myopia The only way to clearly focus a distant object clear onto the retina is with glasses or contact lenses to shift the image onto the retina. Without glasses, myopic people can clearly see objects that are close; just how close is determined by the degree of myopia.
Myopic people need glasses in order to see distant objects. Myopia does not disappear; it tends to increase over time. As the eye grows, the image gets further from the retina and the strength of glasses must be adjusted for this change. It’s like your shoe size that increases as you grow. Similarly, as your child grows, he will need a new adjusted “fit” or prescription of glasses. Your child’s eyeglass prescription is unique and corresponds to the shape of his/her eye. We prescribe the exact numbers with very specific measurements made in the office. This process is known as “refraction”.
Fortunately, the vast majority of myopic people retain the ability to see perfectly well, with optical correction, and have healthy eyes. Our goal is to make sure that your child has perfect, or as close to 20/20 vision as possible WITH glasses on.
Once you have myopia, you do have it for “life”. However, there are alternate options for glasses. Once your child is old enough, you can consider contact lenses. You can also consider laser surgery (LASIK) to correct myopia after the age of 21.
Types of Glasses
Astigmatism is based on the shape of your eye. If your eye is perfectly smooth and round, your vision would be clear. However, if the shape of your eye is more like a football, the light gets reflected in a way that causes blurry vision. Though this deviation from perfect sphericity is microscopic, with enough deviation the light rays passing through one area in the cornea will be focused differently from light rays passing through other areas. When one image is focused into two spots, this is 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, the image needs to be put into a single focal point on the retina. This can be accomplished with glasses or a contact lens (or with laser for adults).
Oh no! This astigmo, sticky-mo, Aston-Martin, stigmata…WHATEVER you call it is a serious disease! Not at all. Astigmatism has a funny sounding name, but 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 LASIK) both spots of light are put into sharp focus exactly on target. Really, that’s it!
Will the astigmatism get worse? Actually, astigmatism tends to diminish over time; some children can outgrow the need for glasses. It is not possible to accurately predict who will outgrow their glasses.
B. Anisometropic Astigmatism
When one eye has more astigmatism than the other, this is anisometropic astigmatism. The problem with anisometropia is that one eye focuses better than the other. The brain receives a clear image from one eye and a blurry image from the other. It starts to ignore the eye with the blurry image and starts to use the “good” eye more. If the discrepancy (anisometropia) is great enough, this can cause problems during visual development (amblyopia). Fortunately, amblyopia from anisometropia can be treated if caught early. First, glasses alone are tried – about 30% of the time this will reverse the amblyopia. If glasses alone don’t do the job then a patch is applied to the good (non-amblyopic) eye, as well, for a period of time. The vast majority of children with anisometropic amblyopia can be significantly improved. Many are restored to normal vision in the amblyopic eye.
Once the vision is better in the “bad” eye, can my child stop wearing glasses? No! The glasses only work to correct the vision when they are worn. They cannot make the astigmatism go away. Your child must wear the glasses as prescribed for the vision to stay good.
When the focusing system (cornea and lens) places an image into focus behind the retina, but not on the retina, this is hyperopia. Most children are slightly hyperopic by nature. To put image into focus the natural lens “pulls” the image forwards, towards the retina; this process is accommodation. However, when there is too much hyperopia for the natural lens to accommodate, the image is blurred. An external lens (glasses, contact lens, LASIK) is needed to put the image into focus.
Hyperopic people cannot properly focus on objects that are close up OR far away. (Don’t get caught up in “far sighted means…” and “near sighted means…” – these terms are misleading.) Looking at objects up close requires more accommodation by the natural lens than looking at distant objects.
Hyperopic people need glasses (or contact lenses) in order to see distant and near objects. Hyperopia does tend to diminish over time. Fortunately, the vast majority of hyperopic people retain the ability to see perfectly well, with correction, if their hyperopia is detected and corrected early enough in life.
D. Anisometropic Hyperopia
When each eye has a different degree of hyperopia, this is anisometropic hyperopia. The problem with anisometropia is that one eye focuses pretty well (or perfectly well) and the other eye does not focus as well. When one eye sends a better image to the brain, the brain does not use the out of focus eye as much. In anisometropic hyperopia, the more hyperopic eye is out of focus at all distances – this is a problem during visual development and can easily lead to amblyopia. Fortunately, amblyopia from anisometropia can be treated if caught early. First, glasses alone are tried – about 30% of the time this will reverse the amblyopia. If glasses alone don’t do the job then a patch is applied to the better (non-amblyopic) eye, as well, for a period of time. The vast majority of children with anisometropic amblyopia can be significantly improved. Many are restored to normal vision in the amblyopic eye.
If my child uses her glasses all the time, she will become dependent on them. Not true. Imagine if people spoke at a whisper all day long around you. While you could hear some if it, wouldn’t this be hard to deal with? Isn’t it wonderful that people speak up at a normal volume? Have you become addicted to or dependent on people speaking up? Or does it just make your life easier… People who need glasses may be able to “get by” without their glasses, but it’s not easy. They see better once they get used to their glasses but this isn’t an addiction or dependence. Wearing glasses is not like using heroin or cocaine: glasses are absolutely safe, legal and awesome when you need them!
Using glasses will weaken the eyes. Nonsense! Why would you deprive your child of the ability to see clearly? In point of fact, not wearing glasses can sometimes lead to vision loss (amblyopia). 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!
Computer and video games hurt the eyes! Who thinks this stuff up?!? The eyes do not “wear out” from looking at things, including computers and video games. Does the sense of smell, touch, or taste wear out from being used constantly? Why would the eyes?
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 cannot be improved to normal with glasses or contact lenses.
The glasses should be worn only to see the board. Without question, children 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 board. However, if your child needs glasses to see well, wouldn’t you want her to see well all of the time?
If my eyes are fine, then how did this happen? Needing glasses is not anybody’s “fault.” But, if it makes you feel better, then you can always blame the other parent and their family. Seriously, while there is some familial tendency for certain refractive errors, the genetics are not so clear-cut. Refractive errors “just happens.”
My child should have her eyes examined every few months now. Children with glasses, particularly younger ones, should have an 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 sooner. Older children (after age 8 or 9) can usually be seen on an as-needed basis.