Why do camera flashes make your eyes turn red?

As your camera's flash goes off, the pupil doesn't have time to react, and the light causes a reflection on the retina which bounces back to the camera. There's a layer on the back of the eye called the choroid which is full of blood causing the reflection color to be red.

Explanation:

Hope this helps

because the brightness is bright and can make you parsley blind it's like the sun but that is way brighter