I know that the whites of our eyes will turn yellow if we smoke heavily. The smoke will tint the whites of our eyes. If we give up smoking or smoke less, the tints will disappear slowly. But there are other possible causes of yellow eyes. If we got an infection in our liver, the whites of our eyes may become yellow too, we should have a thorough exam of our whole body.
The exposure to sunlight will cause the whites of our eyes to turn yellow. We can whiten them with a kind of medicine. But I suggest you not to do that. Wearing a pair of sunglasses is a good choice to avoiding being burned by the UV light and harsh light. Maybe if we take care of our eyes and avoid direct sunlight and other smokes, the white of our eyes will recover on its own.