I'm possibly quite the opposite here. For many years, I could not go outside without sunglasses even on the most overcast of days. I would squint like crazy without sunglasses (however with no eye pain).
But on this past Friday, I went up and back on a trail for 90 minutes and I didn't need sunglasses, even in direct blazing light. The difference was astounding. I had started sublingual methylcobalamin the day before, 2 x 1000 mcg. However, I also had taken a pseudo ephedrine right before the walk.
So today I went outside in blazing sun for a few minutes, with no pseudo ephedrine. I have continued daily b12. The results? My eyes are better than they had been in the sun for years, but maybe not so great as Friday. Maybe the ephedrine gave some pupil constriction that also had helped. More testing to be done.
P.S. The pseudo ephedrine gave me much better breathing - which is what I had been intentionally testing for.
[edit: except that pseudoephedrine probably dilates pupils, so however it might have helped with photosensitivity (if in fact it did), there must be some other reason)