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How does retinal help the eye turn light into a nerve signal?

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oxidation of alcohols — aldehyde Alcohols may be oxidized to give aldehydes, ketones, and carboxylic acids. The oxidation of organic compounds generally increases the number of bonds from carbon to oxygen, and it may decrease the number of bonds to hydrogen.

Retinal, an aldehyde derived from vitamin A, is essential to the process of vision. It functions as a light-sensitive component of rhodopsin, a protein complex found in the retina of the eye.123

When light enters the eye and is absorbed by rhodopsin, it triggers a process called photoisomerization. Specifically, the retinal molecule—which is initially in a folded shape known as 11-cis-retinal—is twisted into a straighter configuration called all-trans-retinal.41

This change in molecular geometry causes the attached protein, opsin, to alter its own shape. This structural shift activates a protein called transducin, which initiates an internal biochemical pathway. These chemical events act as a trigger, altering the release of neurotransmitters and generating electrical impulses that are sent along the optic nerve to the brain, where they are interpreted as visual signals.123