If you do not want to buy a pair of  sunglasses only for for reading in the sun,  and if this practice of reading
outdoors is to your liking, I would recommend you have glasses for presbyopia with photochromic lenses.

Lenses that darken when the light hits them, well, when the ultraviolet light hits them. I emphasized the ultraviolet light, to tell a curiosity that not everyone knows: the photochromic lenses are not activated inside the car. Do you know why?
Good, because car windows have ultraviolet protect them!
On the other hand, it is a good option to use as sunglasses for presbyopia.