Lens flare, as the name suggests, is a product of lenses, and the number, shape, and colour of flares is determined by the lenses in the film camera. Humans with normal vision rarely see lens flare, but it can be caused by astigmatism, LASIK, or other conditions.
It also requires staring into a bright light, so don't do that.
> It also requires staring into a bright light, so don't do that.
I have astigmatism. Most modern headlights produce lens flares when driving at night. Street and traffic lights also. Doesn’t need to be harmfully bright to flare, just brighter than the background.
It also requires staring into a bright light, so don't do that.