A Shiba Inu dog showing eyeshine from the tapetum lucidum. The tapetum lucidum (from Latin meaning "bright carpet") is a reflecting layer immediately behind and sometimes within the retina of the eye of many vertebrates, such as dogs, deer and cats. It serves to reflect light back to the retina, increasing the quantity of light caught by the retina. This improves vision in low light conditions. The reflective effect of the Tapetum lucidum is often called eyeshine. The tapetum lucidum is not present in the human eye, which is why humans have poor night vision.