Eye spot , the Visual system

FOV,
Distance,
Color,
Infrared, Ultraviolet, Light Field, Microwave, Radiation.

With the basic cell, player will have distance limitation( dark fog). FOV will affect when get to multicellular but not in microbe.
about color, player get gray mask on whole srceen, player get visual parts to improve, red green blue visual part.

about other visual system, player can switch vistion

Humans do have blue.

you are right… (minimum is 20 characters)

g