 Stored all-trans-retinyl palmitate is simultaneously hydrolysed and isomerised to 11-cis-retinol by RPE-65.The 11-cis-retinol is oxidized to 11-cis retinal and transported to photoreceptor cells where it binds to opsin to form rhodopsin.Emixustat hydrochloride binds to RPE-65 and prevents the isomerohydrolase reaction.