Corrected entry: When we see the now blind Tuvok shaving, he is using a metal blade, the type still used today, and promptly cuts himself with it. However in TNG, Geordi La Forge (also blind, but using a VISOR) is shown using a bladeless razor with a little light beam that wouldn't cut him. One of these should be available on Voyager, over 10 years later. Lack of power can't a problem, as Tuvok had the lights in his room on the whole time, despite not needing them on account of being blind.
Corrected entry: When Chakotay's comet removal simulation erases 8,000 civilizations, Annorax tells him that 4 billion years before, material from the comet was the catalyst for the eventual development of several civilizations. However, comets, by their very nature, are short-lived, around 10,000 years. There is no way a comet that seeded life across multiple solar systems 4 billion years earlier would still exist.Guy