Tigers and house cats have eyes that seem to glow in the dark. They have no pigment between thei visual receptors, and a mirror-like layer (tapetum lucidum) that reflects light back into the eye. Albinos don’t have the mirror-like layer (so no glow) but they do lack pigment. The lack of pigment impacts light sensitivity, and decreases image clarity.
Introduction
Iris
Lens
Retina
Beyond
Tiger photo by Max van den Oetelaar on Unsplash