Light induces dissociation of the retinal from opsin resulting in changes in the structure of
the opsin. This causes membrane permeability changes. As a result, potential differences are generated in the photoreceptor cells. This produces a signal that generates action potentials in the ganglion cells through the bipolar cells. These action potentials (impulses) are transmitted by the optic nerves to the visual cortex area of the brain, where the nerve impulses are analysed and the image formed on the retina is recognised.