"Eye shine" is the easiest way to spot the cats, who have a tapetum lucidum structure at the back of each eye that reflects light back and helps them see more clearly in the dark.
All lemurs are characterized by a reflective layer (tapetum) behind the retina in the eye, but no fovea or macula lutea; a hairless, moist tip to the muzzle; a noninvasive (epitheliochorial) placenta; comblike forward-directed lower front teeth (with the exception of the aye-aye); and a claw ("toilet claw") on the second toe of the foot.
This provides a mirrorlike surface, the tapetum lucidum, which reflects light outward and thereby allows a second chance for its absorption by visual pigments at very low light intensities.
In addition, nocturnal animals, such as cats and bush babies, are usually equipped with a tapetum lucidum, a reflector behind the retina designed to give receptors a second chance to catch photons that were missed on their first passage through the retina.
On the back wall of the eye, the tapetum lucidum reflects incoming light, thus utilizing the small amount of light available at night to best advantage.
The size of the eyes and visual cortex is probably made necessary by the absence of a reflective layer (tapetum) that the eyes of most other nocturnal mammals possess.
Strepsirrhines have a reflective layer, the tapetum lucidum, behind the retina, which increases the amount of light for night vision, while haplorrhines have no tapetum but, instead, an area of enhanced vision, the fovea.
Most of the slow lorises' primate cousins, including Old World and New World monkeys, great apes, humans, and also tarsiers, have lost the tapetum lucidum, presumably because of a common ancestor that was active during the day rather than at night.
Slow lorises' eyes, like those of many other nocturnal mammals, are quite large, and they possess a reflective layer behind the retina called the tapetum lucidum.
Like dogs and cats, wolves have a thin, reflective film inside their retinas, called the tapetum lucidum, which gives them night vision.
Turn the light off again and the creepy, semi-visible creature with catlike tapetum lucidum is even closer!
