How Do Glasses Correct Visual Problems?

Eyeglasses correct the vision of those with sight eye problems when worn, but glasses are not a permanent solution. They change the direction of light so it hits the eye in a way that sends clear pictures to the brain.

How You See

• The retina is the part of the eye upon which images are focused and sent to the brain. When the eye is functioning properly, it bends the rays of light as they enter the eye so an image is focused sharply on the retina. Eyeglasses work by bending the light to ensure sharp focus of an image on the retina.

Nearsightedness and Farsightedness

• Those who are nearsighted see near images clearly. The eyes in this case focus the image in the front of the retina instead of directly on it. Those who are farsighted see far away images clearly, and the eyes focus the image behind the retina.

Corrective Processes of Eyeglasses

• Glasses are concave -- curving inward in a kind of hourglass shape -- to correct nearsightedness. This expands the light so that it focuses farther back in the eye, directly on the retina. Glasses are convex -- curving outward into a kind of oval shape -- to correct farsightedness. This narrows the light so that it focuses further inside of the eye, directly on the retina.