Re: Strange unexplained light
Not wishing to upset you in any way, LD, but it could be due to posterior vitreous detachment, something which I suffered from.
https://www.nhs.uk/conditions/floate...s-in-the-eyes/
A single flash of light is nothing to worry about, I might add. It is certainly not uncommon. It is all explained in the link above.
If it should happen again or become worse, I'd advise having a word with an optician who will no doubt assure you that there is nothing to worry about. It might be accompanied by seeing 'floaters' as well.
As I mentioned, I had it and mine became sufficiently bad that the experts at the eye hospital offered to do a vitrectomy, which I had, as apart from making my vision worse it would have eventually led to a detached retina - an emergency situation which, if untreated, would lead to loss of sight.
Please don't worry about it. Just keep an eye on it (if you'll pardon the expression).