Juice is a fast delivery method for sugars, and the prepackaged fruit juices you might find in a gas station convenience store almost certainly have added sugar as well as the innate fructose in the fruit juice component.
Also, if you're running low enough on nutrition that your eyes aren't working right, you're also likely to be dehydrated, which can also affect vision.
Also, if you're running low enough on nutrition that your eyes aren't working right, you're also likely to be dehydrated, which can also affect vision.