All-trans-retinol esters (atREs) serve as substrates for retinoid isomerohydrolase (RPE65), located in retinal pigment epithelium (RPE) cells. RPE65 hydrolyses atREs to 11-cis-retinol (11cROL), thus performing an isomerase activity as well as hydrolysis. RPE65 is membrane-bound, this being dependent on the palmitylation of the residue Cys-112 (Takahashi et al. 2009). RPE65 normally undergoes a light-dependent translocation to become more concentrated in the central region of RPE cells. This translocation requires Unconventional myosin-VIIa (MYO7A or USH1B) (Lopes et al. 2011).