What is the most likely cause of this person's color blindness? what does 20/300 vision indicate, and how is that corrected by lasik surgery?

Oxidation may cause the proteins crystalline change shape, aggregate to form cloudy patches in the visual of the person that is called cataracts. The damage due to ultraviolet light and dehydration most likely cataracts interfere the vision. This can be treated through surgery replacing the lens with an artificial lens. LASIK/laser assisted in situ keratomileusis is a computer generated guide laser to let the curve of the cornea reduces for myopia so that the retina can moved back its focus. This does not corrected by glasses, so this is the only way to correct this kind of problem.

the supermassive black hole is in the middle of the galaxy.