Myopia (near-sightedness), hyperopia (far-sightedness), and astigmatism (distorted vision) are what as know as refractive errors.
For proper eyesight, the cornea (the clear window in front of the eye) and the lens (behind the pupil) must properly focus or "refract" light onto the retina (at the back of the eye). If the length or shape of the eye is not ideal, the light may get focused too early or too late leaving a blurred image on the retina.
Myopia, or near-sightedness, is the ability to clearly see objects up close but not those at a distance.
It is an inherited condition usually detected in children between the ages of eight and twelve. Few factors outside of heredity affect this condition. Using dim light, reading too much or nutritional deficiencies do not seem to impact it one way or the other.
Myopia is best treated with eyeglasses and contact lenses which compensate for the elongated shape of the eye allowing the light to focus properly on the retina. As children (and their eyes) grow through the teen years, the condition typically worsens and then levels off in adulthood. During this growing period, new eyeglasses may be needed as often as every six months to correct the problem.
There is no scientific evidence that contact lenses or eye exercises stop the progression of myopia. Refractive surgery is available as a treatment for myopia but most ophthalmologists--medically trained eye doctors--feel that eyes with simple myopia would best be treated with glasses or contact lenses.
© Copyright by the Canadian Ophthalmological Society