I have to respectfully disagree with your statement that " shooting with tinted lenses. It will allow your pupils to enlarge thereby giving more light and better sight picture." The tint in the glasses REDUCES available light, and the large pupils will decrease depth of focus, which in some cases can cause more eye strain. I'm not saying that shooting with sunglasses is a bad thing to do, just disagreeing with your rational.
Regarding shooting iron sights, the focus should be on the front sight, not the target, which, depending on the shooters refractive error, can cause eye strain. Glasses focused for the front sight can be beneficial. IMHO