The opposite however can be said for the non-benthic fish because there is more light near the surface of the ocean, so there would not necessarily be a need for a stronger sense of sight.
This arrangement makes for eyelids that are optically positive, meaning that a certain amount and type of light will be able to enter the eye.
The skin of the eyelid is the thinnest over the eyeballs and begins to thicken as it moves on to the cheek and face of the fish.
One special detail about adipose eyelids is their ability to filter out specific wavelengths of light.
To test for these ranges, different fish eyelids were exposed to light generated from photometers and polarizing microscopes.