Nearsightedness

If you can see objects nearby with no problem, but reading road signs or making out the writing on the board at school is more difficult, you may be near- or short-sighted.

Your eye care professional may refer to the condition as myopia, a term that comes from a Greek word meaning "closed eyes." Use of the word "myopia" for this condition may have grown out of one of the main indications of nearsightedness: Squinting to see distant objects clearly.

Myopia is not a disease, nor does it mean that you have "bad eyes." It simply refers to a variation in the shape of your eyeball. The degree of variation determines whether or not you will need corrective eyewear.

What causes nearsightedness?
Myopia most often occurs because the eyeball is too long, rather than the normal, more rounded shape. Another less frequent cause of myopia is that the cornea, the eye’s clear outer window, is too curved. There is some evidence that nearsightedness may also be caused by too much close vision work. The newest theory is that myopia is more commonplace in children that have had a night light on when sleeping. This appeared to only caused myopia when the light was used on children under the age of two, after this age the   nightlight appears to have no effect on the development of myopia.

How does myopia affect sight?