How close is nearby? It's thought that SN 1054 (Crab Nebula) is the same object as a "guest star" observed by Chinese astronomers in 1054-1056, and that's about 6500 lys away, so relatively close by.

It started as being invisible to the human eye, then went through a process of becoming much brighter before dimming again over a ~2 year period. So much brighter that it was visible in daylight for about 23 days, according to one account.

If I recall correctly, we are currently going through a near-sightedness epidemic that is thought to be caused by things like not spending enough time outside in bright sunlight. Basically, our eyes need environmental cues to properly finish growing, and our modern lifestyles are stunting this growth and forcing more people to develop near-sightedness that would have otherwise had normal vision.