Here comes the college Professor in me:
Before I retired a large part of my design firms practice was designing hospital and outpatient medical facilities (not doctor’s offices). I have never met, nor heard of, from a reliable source, of any person who has had lasting-temporary or actual-permanent eye damage from a laser diode. With that said I will speak to the “Laser Bogeyman”;
I do have goggles that I use when I test an focus. This is an eye fatigue issue mostly. These are laser diodes, very different than “real lasers” as it were. Real lasers (PTP, Argon, Carbon Dioxide, Synthetic long-crystal, and so on) produce coherent stacked waves of light. One example to contrast a laser to a laser-diode is cutting ability; a real laser can cut clear material, a laser diode generally can not.
Carbon Dioxide lasers (the standard for laser surgery) being a “Real Gas Laser” obliviates (vaporizes) human tissue as it cuts, whether clear, pigmented, or translucent, human tissue. They cut and cut fast. Very dangerous without goggles.
Gas lasers are the standard for; cutting, obliviating, and welding just about everything. Small laser diode engraving and cutting machines are more of a novelty than anything else. They are too slow and clumsy to out-perform most mechanical cutters. I just purchased a new vertical mill and new horizontal mill for my model studio. I passed on laser tech as a real CO gas laser cutting system starts at about $60,000.00.
In closing, and to answer the actual question posed, I have shot myself, at point blank range “in the eye” without goggles, on several occasions (no, not on purpose…). The lasers were as high as 6,000mw (6 watts). Why am I not blind? Should I not at least have a leaky eye or a new blind-spot? The good news is I am just fine and so are my eyes.
Here’s the deal; our eyes do not like bright light (try looking directly into the sun) nor dust for that matter. The eye has an “eyelid” and multiple “muscular systems” that are autonomic. These interlocked systems protect the retina and cornea from damage of all sorts. When I shot myself by accident my eye; rotated away from the light source, the iris closed, the eyelid closed, and my retinal rods and cones produced an enzyme to protect themselves (this enzyme is often referred to as “seeing spots” of the color opposite bright light seen, aka yellow for a blue laser).
My eye would have to get anesthetized to make the protection systems inoperative before a laser diode could do any real damage.
I’m not advocating any irresponsible action like selling 6 watt lasers to kids. But I do think understanding the real facts and risks are valuable. In the end the number of lost-eyes to debris that flies of “drill presses” and “cordless drills” represents the real-and-present danger to DIY guys of all kinds. If we are all going to value our eyes let us all first put on “ordinary” safety glasses when we work. This is a risk OSHA actually tracks.
I propose that more persons may have gone blind in one eye by “missing their mouth” while eating at Denny’s and “sticking their Fork in their eye” than are blind from a laser diode…See you all at Denny’s!! p.s. don’t shoot yourself in the eye to check my facts and, stick with dull forks??? Safety first.