|Why are lasers harmful to your eyes?
You eyes treat the laser light as though it came from a very distant object with a very small size. As a result, your eyes focus all of the laser light to a single tiny spot on your retina because that is where light from a tiny, distant object should go. However, there is a lot of power in the laser light and when all of that power lands on only a few cells at the surface of your retina, it cooks those cells. Its very similar to what happens when you hold a magnifying glass in sunlight and create a white hot spot on a piece of wood. With powerful lasers, damage can be done to your retina very quickly.