The covex lens in front of the eye is able to focus the light on the retina as shown on the right. However, people suffer from conditions such as short and long sightedness where the lens is unable to focus incoming light on the retina.
Sometimes
the lens does not change shape enough to focus the light on the back of
the retina. The light in the case shown on the left is focused in front
of the retina. The image formed at the retina appears blurred. This is known as shor tsightedness.
An optometrist may prescribe concave lenses. Click to see how these lenses bend, refract, light onto the retina.
People with long sightedness can see objects far away clearly, but have trouble focusing on objects close by. By providing corrective lenses
placed in front of the lens the light is focused on the retina where a
perfect image is formed.
Click to see
how a convex lens corrects this condition.
A person with short sightedness can see
A person with long sightedness can see
How does the lens focus light for perfect vision?
A person with short sightedness has glasses with
The human eye has a lens that
A person has severe short sightedness. A
with a
is used to make glasses for this person.
