I've taken 3-4g of aspirin consistently for months without much change in eye color but my baseline is A20s. Getting sun seems to make my eyes brighter, but that might just be contrast with darker skin.
@13 how many calories a day are you eating? tracking that and being consistent and gradually increasing that, while running a proper program, is usually the move. get like 3000 kcal/day (rice, OJ, milk, and yogurt will be your best friend here) and you'll gain weight fast. and if that doesn't work, increase your calorie count.