Amount of light the eye can withstand.

Factual Questions
1

We all know that at 120 dB, one’s ears take a beating. In fact, hearing begins to be lost at that level. That’s why people who work on the tarmacs of major airports wear big sound-resistant earmuffs.

Analogously, the eye takes damage from light that’s too intense. Staring at the sun is not a good idea, as the rods and cones can only take so much. So, how much light can one withstand with no protection whatsoever (not even the eyelids)? Does it vary by frequency (excluding ionizing radiation)?

Does our auditory tolerance vary by frequency?

2

[nitpick]
Hearing loss can begin with continuous exposure to just 85 dB.
[/nitpick]

3

This PDF document has ANSI limits for exposure to light of various wavelengths, and other information about light exposure and vision.