on Tuesday, September 11, 2012
Myopia, also called nearsightedness, is a common problem where light rays passing through the eye are focused before they reach the retina. The retina is the light sensing membrane at the back of the eye that contains the rods and cones that collect and transfer the light via the optic nerve to the brain that then produces the images that we call ‘seeing’.
Ideally, light passing through the eye will come to a sharp focal point at the retina. When light is focused in front of the retina, as in myopia, distance vision becomes blurred. The degree of blur depends on how far the focal point is in front of the retina. While distance vision is blurred, near vision is usually clear. Myopia in children is usually the result of the length of the eye being too long with regard to the focusing power of the cornea and/or lens or the focusing power of the cornea and/or lens being too strong for the particular length of the eye.
The most common signs that should alert parents that their child may be myopic are squinting when looking at objects that are not close and sitting close to the TV. Headaches are also common as are complaints of ‘eyestrain’. Poor grades may be another sign as the student may not be able to see the board in school clearly. Difficulty in sports may also be due to myopia. There is a genetic basis to myopia. If both parents are myopic, there is a greater chance that the child will also become myopic. The age at which a child develops myopia varies, but generally, 7 to 12 years old is a common age range.
Blurred distance vision due to myopia is most frequently corrected by prescription glasses or contact lenses. If the child is mature enough to handle contacts, daily disposable contact lenses, such as CooperVision’s Proclear 1 Day lenses, are recommended.
Myopia control is the subject of much research as there is a significant increase in the prevalence of myopia globally. Several studies have demonstrated that taking part in outdoor activities for some portion of the day results in less myopic development. One theory is that the ambient outdoor light is a key factor in less myopic development. Certain topical drugs can be used to slow the progression of myopia, but they cause a reduction in the ability to see up close and they also cause the pupil to dilate and therefore increase light sensitivity. The use of special bifocal contact lenses and lenses that reshape the cornea have both demonstrated some ability to slow the development of myopia but are not yet approved for that use.
If your child is having trouble academically or in sports, squints when looking at objects that are not close, sits too close to the TV or complains that he/she can’t see objects in the distance that others can see, have an evaluation by an eye doctor to determine the underlying cause.