$A$ 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.......$D$

For a normal eye,the cornea of the eye provides a converging power of $40\, D$ and the least converging power of the eye lens behind the cornea is $20\, D$. Using this information,the distance between the retina and the cornea-eye lens can be estimated to be ......... $cm$.

An imaginary line joining the optical centre of the eye lens and the yellow point is called as

The far point of a myopic person is $80\, cm$ in front of the eye. What is the power of the lens required to enable him to see very distant objects clearly?

When the human eye is focused on an object,at what position are the ciliary muscles least strained?

$A$ person's near point is $50 \, cm$ and his far point is $3 \, m$. The power of the lenses he requires for $(i)$ reading and $(ii)$ seeing distant stars are: