 In the Visual Cycle, exposure to light causes 11-cis-retinal to isomerize to all-trans-retinal (as part of the rhodopsin complex).The isomerisation results in the release of chemical energy, which is processed into an electrical signal (by a series of different cells) that is transmitted to the brain.The all-trans-retinal is released from opsin, reduced to all-trans-retinol, then transported from the photoreceptor cells back to the RPE cells, where it is stored for recycling and future use as retinol palmitate.