This term describes a condition called nearsightedness — when someone has trouble seeing objects that are far away. Usually, someone with myopia can read a book or smartphone without trouble. But they might view objects even an arm’s length away as fuzzy and out of focus.
When light enters the eye, it passes through the outer layers — the cornea — and then through a lens. The lens focuses the light to a point on the back of the eyeball in an area called the retina. There, nerve cells process the information and pass it on to the brain.
When the eyeball is a perfect sphere, the light becomes focused on just a small point on the retina. That produces perfect vision. But if the eyeball is slightly too long from front to back, the light will focus to a point before it hits the retina. Then, the light spreads out again. The more the light spreads out before it hits the retina, the fuzzier the image will appear to the viewer. A too-thick cornea will also make the light focus too early. Both of these changes can produce myopia.
Glasses and contact lenses can help people with myopia. These objects help focus light when the eyes aren’t quite up to the job.