Photochemistry of Vision | Alisha Navalkar

Photochemistry of vision highlights how the chemical changes in the eye enables the humans to see. In the picture above the parts of the eye are mentioned. An object is clearly visible only when the light coming from the object is focused on the retina. Rhodopsin is the photopigment used by the rods and is the key to night vision. Intense light causes these pigments to decompose reducing sensitivity to dim light. Darkness causes the molecules to regenerate in a process called “ dark adaptation” in which the eye adjusts to see in the low lighting conditions. The process of vision is triggered by the photochemical isomerization of the light absorbing pigment molecule retinal, which is the aldehyde derived from Vitamin A, bonded to a membrane protein called an opsin