When the power of the eye lens increases,a defect of vision is produced. This defect is known as:

The retina of the eye acts like the ........ of a camera.

The far point of a myopic eye is $250 \, cm$. What is the focal length of the lens required to correct this defect?

$A$ person can see objects clearly when they lie between $40 \ cm$ and $400 \ cm$ from his eye. In order to increase the maximum distance of distant vision to infinity, the type of lens and power of the correction lens required respectively are

To remove myopia (short-sightedness),a lens of power $0.66 \, D$ is required. The far point of the eye is approximately ....... $cm$.

For a normal eye,the least distance of distinct vision is......$m$.