Fillers or laser treatment for under-eye troughs: What's the better option for a 30-year-old female non-smoker?

For under eye hollowness, volume restoration would be a better option along with a lower blepharoplasty (if there is excess skin, and fat tissue in the bags under the eyes). For this fillers can be used as well as fat grafting. You may want to have a try with fillers first as they are temporary. A more permanent option is fat grafting, which is your own tissue and contains stem cells therefore it will have a more rejuvenating effect. Each individual has a different anatomy so treatments should be tailor made. It's best to consult a board certified facial aesthetics specialist in person and discuss your options.