The circular part in the centre of the retina is called:

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

The near point and far point of a normal human eye are respectively:

$A$ person can see objects clearly only when they lie between $50\, cm$ and $400\, cm$ from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens the person has to use will be

$A$ man suffering from short-sightedness (myopia) is unable to see objects distinctly at a distance greater than $2\,m$. The power of the lens required to correct this defect should be.......$D$

Hypermetropia is a: