Why do the eyes of big cats glow in the night ?
The glow of red human eyes is a little like the glow of the moon. It’s the reflected light of a far greater light source. The flash of a camera travels through the pupil and hits the back of the eye – the retina. The retina reflects the light back towards the camera, but it does so just a little differently than it came in. Like most of the insides of our bodies, the retina is an icky red mess, with blood vessels criss-crossing it. Those blood vessels color the light that shines back red. We literally dye the light red with our blood. Refer this website to get furthermore information.