Wednesday, 10 April 2013
What is night blindness?
Night blindness means that a person cannot properly orient there eye sight in the dark. The eye usually becomes accustomed to dark but with night blindness this doesn't happening the normal way.
One can be born with night blindness or have gotten eye disease retinitis pigmentosa, where the field of vision will become less and less eventually ending up with total blindness. More likely, it is a question of a lack of vitamin A, flavonoids and carotenes that makes some see worse than others in the dark. These dietary factors are namely the chemical precursor and are needed for the eye's Visual purple, wich converts light to electrical impulses. They are sent to the brain's vision center, where they are registered as visual impressions and pictures.
When the light passes through the eye's pupil, the light goes on the retina, which is made from the aforementioned dietary factors.
The eye has two kinds of sensory cells-rod and cone cells. The rods are the most sensitive, and we use them in the dark.
When a person cannot detect the weak night lights, is it due to a lack of Visual purple in the rods. It gives us night blindness.