The eyes of the mantis shrimp are mounted on mobile stalks and can move independently of each other. They are thought to have the most complex eyes in the animal kingdom and have the most complex visual system ever discovered.[19][20][21] Compared to the three types of photoreceptor cells that humans possess in their eyes, the eyes of a mantis shrimp have between 12 and 16 types of photoreceptors cells. Furthermore, some of these shrimp can tune the sensitivity of their long-wavelength colour vision to adapt to their environment.[22] This phenomenon, called "spectral tuning", is species-specific.
Each compound eye is made up of up tens of thousands of ommatidia, clusters of photoreceptor cells.[20] Each eye consists of two flattened hemispheres separated by parallel rows of specialised ommatidia, collectively called the midband. The number of omatidial rows in the midband ranges from two to six.[19][20] This divides the eye into three regions. This configuration enables mantis shrimp to see objects with three parts of the same eye. In other words, each eye possesses trinocular vision and therefore depth perception. The upper and lower hemispheres are used primarily for recognition of form and motion, like the eyes of many other crustaceans.[19]
Mantis shrimp can perceive wavelengths of light ranging from deep ultraviolet (UVB) to far-red (300 to 720 nm) and polarized light.[20][24] In mantis shrimp in the superfamilies Gonodactyloidea, Lysiosquilloidea, and Hemisquilloidea, the midband is made up of six omatodial rows. Rows 1 to 4 process colours, while rows 5 and 6 detect circularly or linearly polarized light. Twelve types of photoreceptor cells are in rows 1 to 4, four of which detect ultraviolet light.[19][20][24][25]