The small amount of pupil dilation in the eye, due to the wearing of sunglasses, is not known to cause any problems. I think there is no need to worry too much about it,it should not be a serious issue.
Actually sunglasses absorb UV more strongly than visible light. That is to say, they protect your eyes from UV problems instead of bringing any of them to you.
I don’t know for sure but I have never heard of it. Wearing a pair of sunglasses does not increase your exposure to UV radiation. On they contrary, I think you will benefit from sunglasses.