Well, let's look at the math. 100mw over a circle 2.5m in diameter gives a power of 2 microwatts per square mm. The iris of the eye can open to 7mm at night, which is 38 square mm. The total power to the eye is then 77 microwatts, or 0.077 mw. Not enough to cause permanant damage, I think.
(Don't do math before lunch. Previous version of this post was in error)
Last edited by MarcK; 30th November 2007 at 19:41.
Reason: Math Error