Please help me in understanding something which confuses me a lot . I am myopic, my number has been stable for years and has dropped by some points in the past few months . Sometimes I get a random black spot in my vision comes and goes in a second or sometimes with eye movement I see them but they are not persistent . I see them mostly in artificial lights and sometimes in natural light indoors , and it doesn't have to be a brightly lit surrounding . My dilated exam in December was normal .