The very first time I had any problems with my vision at all was February 2020 when I got sick with some unknown infection that had the strangest mild, cold-like symptoms I ever experienced. Lasted about 3 weeks. It was probably coronavirus, but who knows.

My vision would blur every night at about 8pm around the same time I would feel pretty dizzy. That actually was a lasting effect beyond the 3 weeks of the other symptoms. It eventually subsided also.