$A$ myopic person has been using spectacles of power $-1.00\, D$ for clear vision. During old age,he also needs to use separate reading glasses of power $+2.00\, D$. Explain what may have happened to his eyesight?

State the function of the pupil and ciliary muscles.

Which part of the eye is responsible for changing the focal length of the eye lens by adjusting its thickness?

$(i)$ Write the range of distance for a person having normal vision.
$(ii)$ $A$ person needs to use glasses for reading a newspaper. Identify the defect in his vision and the type of lens he would need to correct it.
$(iii)$ Sometimes when we enter into a dark room from bright sunlight,we are unable to see objects clearly. Why?

Sometimes you see a person reading the newspaper by placing it far away from their eyes. Which defect is the person suffering from? How can this defect be corrected?

How are we able to see nearby and also the distant objects clearly?