User:Ukloehle/Refractor lentis

Fish have a refractor lentis which allows changing the lens position within the pupil, as well as the lens-retina distance. Predatory fish such as the piranha have very well developed accomodation.

In fish, the pupil is relatively immobile and unresponsive to light. The pupil is used as a focus indicator, optimization of the light path is utilized through the lens placement. This characteristic is used as camouflage.

Adaptation to high light levels is achieved through pigmentation in the cornea, lens, and retinomotor movement.

This is not characteristic in any other species.