How long do you have to hold a normal pen laser in your eye before it blinds you?

NEVER DO THIS: An interesting question with a simple answer. Never shine a laser into someone's eyes. First, there are multiple types of laser pointers. Some low power, some higher, but why risk this at all? So how long you ask? Zero seconds. Don't do it. I found the following, however, which may answer better: http://www.Drgreene.Com/qa/laser-pointers-and-eyes.