Question

What is the power of accommodation of an eye?

Answer 1

Hint – In this question think of the fact that how human eyes are able to adjust to near and far objects clearly, without putting unnecessary strain on the optic nerve.

Complete step-by-step answer:
Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length.
Power of accommodation of the eye is limited, it implies the focal length of the eye lens cannot be reduced beyond a certain minimum limit.
The process by which certain muscles (called ciliary muscles) function, to change the focal length of the eyes so that the image is clearly formed on the retina is called the accommodation of the eye. This will vary for near and distant objects and also for objects moving away or towards the eye. By adjusting the focal length, the eye is actually changing its lens power as well isn’t it? This is called the accommodating power of the eye. Literally. the eye’s power to change its power.
You can actually put this power of your eye to test. Keep your finger in front of you and try to focus only on the finger. You will notice that objects in the background tend to get blurry. Now do the opposite. Keep your finger in front of your face but focus on something in the background. What happens now? Your finger is blurred.
The Power of accommodation for a person with normal eyesight is around 4 Dioptre (unit of lens power).
So this is the required answer.

Note – The standard power of accommodation for normal eyesight is measured in dioptre, dioptre is a unit of refractive power and it is equal to the reciprocal of the focal length in meter).