Compared with common sunglasses, fitover sunglasses are more helpful especially for people with poor vision and always wearing prescription eyeglasses. They allow them simply slip a pair of sunglasses over them so as to shield eyes and provide vision aids.
Though there are prescription sunglasses, they are more expensive. For people who want to saving money, fitover sunglasses are the best choices to save money.
It is much cheaper to wear fitover sunglasses than wearing prescription sunglasses. People who want to wear prescription glasses together with sunglasses all the time, it is a better choice to wear fitover sunglasses rather than prescription sunglasses. Besides, it is much more convenient to wear fitover sunglasses because you don't have to switch between two pairs of glasses. However, if you wear your glasses only occasionally, fitover sunglasses are not suitable for you because there's an existing glasses pair and you should wear them all the time.