Question

some aged people use bio focal length in their spectacles give reason​

Answer 1

Answer:

because they suffered from myopia as well as hypermetropia

it happen because of their aged and their cilliary muscles are weak

mate I hope it help u

Answer 2

This problem is known as Presbyopia .

And they have shortsightedness as well long sightedness due to increase age peblem.

that's why they use bio focal length ...