Tapetum lucidum

Dogs have eyeshine, humans do not

The tapetum lucidum (Latin: "bright tapestry", plural tapeta lucida)^[1] is a layer of tissue in the eye of many vertebrate animals, that lies immediately behind or sometimes within the retina. It reflects visible light back through the retina, increasing the light available to the photoreceptors. This improves vision in low-light conditions, but can cause the perceived image to be blurry from the interference of the reflected light.^{[citation needed]} The tapetum lucidum contributes to the superior night vision of some animals. Many of these animals are nocturnal, especially carnivores that hunt their prey at night, while others are deep sea animals. Although strepsirhine primates have a tapetum lucidum, humans and other Haplorhine primates do not.