Question

Draw a diagram to show how Hypermetropia is corrected.

Answer 1

Hint: Our eye is designed to be able to see all far and near objects. The shortest distance at which we can see clearly is 25 cm while the longest distance is infinity. Sometimes when our muscles weaken or due to old age our vision can become blurred, when we are unable to see the nearby objects clearly, this condition is called Hypermetropia.

Complete step-by-step solution:
Hypermetropia, also called long-sightedness is a condition where the nearby objects appear blurred but faraway objects appear clearly. In this condition the image of nearby objects is formed behind the retina.

The muscles around our eye lens are not able to contract enough for the image to be formed on the retina therefore, it forms behind the retina. We can use a convex lens to increase the overall power of sight so that the image of nearby objects forms on the retina itself.
Hypermetropia can be corrected as follows-

When we add a convex lens to correct the eye lens, the resultant focal length decreases hence the power increases.

Additional Information:
When we are unable to see far-away objects correctly, such a condition is called myopia. Myopia is corrected using a concave lens. Astigmatism is a condition in which the lens is differently curved and it leads to blurred vision. Cylindrical lenses are used to correct astigmatism.

Note:
The eye has many parts; the cornea is the coloured part which collects all the light for the image to be visible, the muscles expand or contract accordingly to change the shape of the lens, retina is the screen where image is formed, optic nerve takes the signals from the retina to the brain which interprets the signals, the image formed on the retina is inverted.