Which isn't to say that 1550 nm light is safer -- the mode of destruction is just different, e.g. corneal damage leading to cataracts or surface burns rather than retinal damage.
As I understand it, it’s largely a focusing issue. Close to the visible range, a distant point source gets focused to a point on the retina. At 1550nm, the energy is deposited uniformly on the cornea unless the laser is focused to a tiny spot on the cornea.
edit: I don’t know to what extent this is relevant, but humans can regenerate the corneal epithelium. Think about all the sand you’ve gotten in your eye as a kid, and the fact that it probably didn’t accumulate enough damage to blind you.
amluto|7 years ago
edit: I don’t know to what extent this is relevant, but humans can regenerate the corneal epithelium. Think about all the sand you’ve gotten in your eye as a kid, and the fact that it probably didn’t accumulate enough damage to blind you.
trhway|7 years ago
[IANAD] corneal damage seems to be more preferable as it is fixable