What if your human eyes did not reflect light?

I can’t fully answer the question, but I know that the retina reflects red, which explains the red-eye effect in photos taken with the subject facing the lens and light source. Other animals (esp. nocturnal ones) have a much more reflective tapetum lucidem layer behind the retina, which enhances “eyeshine.”

From most angles (i.e., off-axis) the pupil appears black, indicating that most of the light falling on it is absorbed.

If your eyes didn’t reflect light, then it would be impossible for another human (or anything that detects light such as a camera) to see your eyes. This is true of anything that doesn’t reflect light.

Hmmmm red contact lenses would render us invisible?

If my human eyes did not reflect light, then perhaps my inhuman eyes would. No everyone has inhuman eyes. But I was born lucky, I guess.