what do you mean by myopia ? how it is correct ? what are it causes?
Answers
Nearsightedness
Myopia: Nearsightedness, the ability to see close objects more clearly than distant objects. Myopia can be caused by a longer-than-normal eyeball or by any condition that prevents light rays from focusing on the retina.
Myopia is corrected by spectacles or contact lenses with lenses which are 'minus' or concave in shape. So if you're short sighted, your prescription will have a minus lens power, e.g. -2.50D.
What Causes Myopia? blame. When your eyeball is too long or the cornea -- the protective outer layer of your eye -- is too curved, the light that enters your eye won't focus correctly. Images focus in front of the retina, the light-sensitive part of your eye, instead of directly on the retina
Myopia, or short-sightedness, occurs when the eyeball is too long so it affects how the cornea and lens focus. This means objects in the distance appear blurry because light rays are focusing at the front of the retina rather than directly on its surface.