You are probably aware that vitamin A is good for your sight, specifically night vision, but how does it actually achieve this? Well what is pretty well known is that insufficient levels of retinol (the most active form of vitamin A) results in so-called night blindnes. This is because retinol is required in the formation of 11-cis Retinal which crosses the interphotoreceptor matrix (in the eye) to the rod cells where it binds to a protein called opsin forming the visual pigment rhodopsin. Rhodopsin rich rod cells are superbly adapted to detecting very small amounts of light and hence play an extremely important role in night vision.
11-cis Retinal is converted via isomerization to all-trans retinal through the catalytic actions of a light photon and this process of isomerization triggers a cascade of events that ultimately result in the generation of an electrical signal to the optic nerve. The optic nerve in turn generates its own nerve impulse which is conveyed to the brain where it is interpreted as vision.
SUMMARY
Vitamin A in sufficient doses is necessary for healthy vision, especially at night and for optimal health of the eye apparatus.
Recommended Dietary Allowance (RDA) For Vitamin A
Recommended Supplements
Recommended Reading
