Learn why you sometimes have glowing red eyes in photographs.
If you look at a bright lamp and then close your eyes, why can you still see the light?
If you've ever rubbed your eyes and seen faint sparkles of light, you have demonstrated a surprising fact of sensory physiology.
We don't perceive color in our peripheral vision because we have no cones, which sense light frequencies, on the outer edge of our retina.
Contact lenses bring objects into closer and clearer focus than glasses.
Have you ever been staring into space, or gazing up at a clear, blue sky and suddenly noticed clusters of tiny dots and swirls?
Scientists tested eighteen reindeer with light, and found that their eyes responded to both visible light and ultraviolet.
Why can't we landlubbers focus underwater without goggles?
Have you ever noticed that Siamese cats are cross-eyed? In fact, that's the only way a Siamese cat can see straight.
Did you know that the thaumatrope was invented by an English physician named J. A. Paris in 1926?