There's no appreciable wavelength-specific filtering going on in an eclipse since the moon has no atmosphere. (The corona does have a different spectra than th

There's no appreciable wavelength-specific filtering going on in an eclipse since the moon has no atmosphere. (The corona does have a different spectra than the surface of the sun, but that's not the issue here. The corona is dim enough to look at.) The problem is that there is so much invisible energy in proportion to visible energy. So blocking a large portion of the sun's disk, so your eyes no longer detect too much visible light, still allows too much total energy which fries your retina when focused into a very small area by your eye's lens.