Vitamin A (its ability to boost vision and keep your eyes healthy) absorption is a complex process similar to lipids. It includes the emulsification and hydrolysis of its esters in the lumen of the gastrointestinal tract, its adsorption and transport into mucous membrane cells, the re-esterification of retinol into them and the subsequent intake of vitamin A into the liver, as part of chylomicrons. What kind of chemical reaction is the most important in the vision processes for transformation of retinol to retinal?