Question

What is meant by least distance of distinct vision?How does this vary between the very young and old people?

Answer 1

as our eyes have convex lens and this eye has a special ability called ability of accommodation of eye, helps us to see nearer as well as distinct object with the same lens present in our eyes. but our eyes also have a fixed range to see clearly that is from 25 CM to infinity. object placed between 25 cm to infinity can be seen without any stress on our eyes but object placed before 25 CM, we cannot see it properly without any strain on our eyes. this is the least distance of distinct vision. this does vary from young and old people as young people have strong and active ciliary muscle, power of accommodation works properly. whereas in old people the ciliary muscle got loose and inactive hence their power of accommodation of eye is also affected, resulting in increase of distance of distinct vision.
thank you

Answer 2

Answer:

The minimum distance at which objects can be seen distinctly without strain is called the least distance of distinct vision.