Why do some animals eyes glow in headlights, but human eyes don't?

Many animals that are either nocturnal or benefit from increased low-light vision have a feature in their eyes called atapetum lucidum, which is basically a special reflective layer in the back of the eye that reflects more light into the retina, which increases the ability of the retina to capture light.

Humans and most other primates do not have a tapetum lucidum. It's very pronounced in nocturnal hunters like cats, which is why cats are frequently seen with glowing eyes in photographs.

Humans have something similar, but it's the blood vessels in our eyes that reflect the light in camera flashes causing "red-eye"

source: https://www.reddit.com/r/explainlikeimfive/comments/444wp6/eli5_why_do_some_animals_eyes_glow_in_headlights/