system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why is directly looking at a solar eclipse bad for your eyes?
gpt
Your eyes adjust to the total light in your field of view, not the brightness of any particular object in your field of view.

So during an eclipse, there's less total light, however any visible portion of the sun is just as bright as it is usually, which is bright enough to physically damage your eyes.

Thus, your iris will accomodate by expanding, allowing even more light than usual in, when the light is already intense enough to cause harm normally.