As you know our eyes work like a camera. The camera film of our eye is the Retina, a thin coating of millions of tiny nerve cells called rods and cones. In normal eyes, the picture is formed exactly on the retina. In the eyes of people who are short-sighted, the picture is formed behind the retina in the eyes of people with long-sight. Short-sighted people can't see things clearly far away fom them. Elderly people often cannot see clearly objects that are close to them. Wearing spectacles can help people with these eye troubles.
Short-sighted people are povided spectacles with concave glasses that help to focus the image on the retina instead of in front of it. Long-sighted people are given convex glasses that help to bring the image forward on the retina instead of behind it. Nowadays contact lenses are also used to correct vision.
Short-sighted people are povided spectacles with concave glasses that help to focus the image on the retina instead of in front of it. Long-sighted people are given convex glasses that help to bring the image forward on the retina instead of behind it. Nowadays contact lenses are also used to correct vision.
0 comments:
Post a Comment