Question

Referring to specific anatomical structures, how is vision affected by the physical structures of the eye?

a) Eyeballs of a newborn are shorter (front to back) than the eyes of an adult

b) In some individuals, continued growth of eyeballs front to back exceeds the average rate

c) In some individuals, continued growth of eyeballs front to back is slower than the average rate

d) During aging, overall melanin production tends to decline

Answer 1

A)Normal newborn have a decreased eyeball axial length than the adult.Axial length(front to back) of the children increases with aging and attain a maximum level at the age of 12 -13 year.

B)When the growth of Anteroposterior diameter of the eye is showing a high rate than the normal growth can result in a condition called Myopia.in this patient the image is formed infront of retina.Patient will have blurring of vision in looking far object and the near objects will be normal

when the growth of front to back diameter of the person is slower than the normal rate can result in a condition called Hyermetropia.The image will be formed behind the retina.

This people have a blurring of vision when looking nearer object.

During aging the overall production if the melanin in the eye increases and it is deposited mainly in the iris and iris look darker.

in some patient mainly caucasians have a lighter urus with aging,it is due to the decreased production of melanin.This will lead to overexposure and photosensitivity