Light perception takes place in the cone and rod photoreceptor cells of the retina, a structure at the back of the eye, through a set of proteins denominated phototransduction cascade proteins. (scilifelab.se)
Any defect involved in these processes of phototransduction and transmission in the retina lead to visual impairment. (istem.eu)
They have a very specialized apical membrane structures called the outer segment (OS), in which phototransduction molecules function. (sciencedaily.com)