This is unrelated in a way, but I am both sensitive to light and afraid of the dark! I have glasses that adjust to sunlight and even some room lights, I have noticed. They are just normal glasses, with the added feature of being light sensitive to sunlight. Anyway, I think sensitivity to certain things goes with PTSD, like whatever was present and in abundance during our trauma(s) will probably to some degree affect us when it happens. As it happens, both my traumas had either light or total darkness as their atmosphere so light is something I am sensitive to in all its many forms.
How do I deal with this? I can't really, I guess. Lightness and darkness are parts of every day. I do have my windows either covered or shaded at least to some degree. I have a light I keep on in my home at all times, which lights the whole place pretty much, but only slightly, not brightly. I have a nightlight in the bathroom, the only room that that one light does not reach.
I guess you just have to use your imagination about how to deal with your issue. Like have you thought of asking the offended(s) to stop doing these things that upset you? Have they agreed to and tried and been unable to do so? You know, sometimes simple communication can do wonders.