Slender-snouted crocodiles are assumed to see in color and have great night vision, but their vision is limited underwater.
When above the surface of the water, vision is an important pathway for perception of a crocodilian’s environment. It’s assumed that crocodilians can see in color because their eyes have both rods and cones. Their eyes also contain a tapetum lucidum, a layer of guanine-rich retinal cells that amplify incoming light and greatly improve night vision.
However, when hunting underwater, a semi-transparent third eyelid closes over the eye, likely limiting vision to light/dark differentiation. Touch receptors and the ears are likely to be the primary sense organs used while crocodilians are underwater.