What is Power of Accomodation of Eye?

The ability of the eye lens to change its focal length is called power of accomadation

This focal length of eyes is changed with the help of cillary muscles as explained below


When eyes are looking at distant objects

Cillary muscles are relaxed

These pull the eye ligaments tightly

Due to this, eye lens become streched and become thin

So, focal length increases


When eyes are looking at nearby objects

Cillary muscles are contracted

Due to this, eye ligaments are loose

Eye lens become thick and we are able to see nearby objects

So, focal length decreases


What is Range of Accomodation reached by Normal Eye?

Human Eye can see objects whose distance is between Infinity and 25 cm from Normal Eye

What is Near and Far Point of Eye?

Farthest Point where eye can see is called Far Point of Eye

It is infinity


Nearest Point where eye can see is called Near Point of Eye

It is 25 Cm from eye


What Is Cataract?

In old age, crystalline lens of some people become milky and cloudy

This is called cataract

It causes partial or complete loss of vision

It can be avoided with the help of cataract surgery

Eye with Cataract.jpg

Why we have 2 eyes for vision and not one?

It helps us to have wider view

With one eye, a human being can see a horizontal field view of 150 degrees

With 2 eyes, a human being can see a horizontal field view of 180 degrees


Since both eyes are separated by a distance of few cm, both eyes see different images

Our brain is able to combine 2 images into one and hence we are able to see image with wider view

Hence, we are able to detect faint or far way objects because of our 2 eyes



It helps us judge distances accurately

Because our eyes are separated by a few centimetres, each eye sees the object from different angles.

So, the brain sees two slightly different image

The brain combines the two images into one, using the extra information to tell us how close or far away things are.

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo