The Mechanism of Vision
Steps to vision
Light passes through the cornea and the iris regulates the amount of light that enters the pupil.
The light entered from the pupil will pass through the vitreous body and project the information from the light onto the macula (retina).
The photoreceptor cells in the macula (retina) will convert the light signal into electrical signals and which are then transmitted through the optic nerve to the brain.
Once the brain receives the signal, the process to "see" is complete.
What is happening in the retina
As mentioned above (No. 3), there are two types of photoreceptor cells in the retina. The cone photoreceptor cells and the rod photoreceptor cells. The cone photoreceptor cells detect and identify colors whereas the rod photoreceptor cells detect the density of the light and has the role of scotopic adaptation.
When the photoreceptors receive light, a visual pigment called the rhodopsin in the rod cell will convert the light signal into electrical signals in order to transmit information to the brain.
The electrical signals are caused by the visual cycle of bleaching and recycling of the rhodopsin. Each time the rhodopsin bleaches, an electric impulse is created. Therefore, if the recycling is not smoothly done, our vision will be blurry and unclear.
How does Anthocyanin help?
During the visual cycle of bleaching and recycling of the rhodopsin, the process of recycling gets heavy due to exhaustion of using the eye too much and by receiving large excess of light. Anthocyanin supports the recycling process so it would become smooth.