Hello, as well all know, designer sunglasses are very fasionable, and it is special and good on it design, so I think that fashion trends to be the reason way more and more people like wearing designer sunglasses. Almost all the sunglasses brands like Versace, Dolce Gabbana, Oakley, Chanel, Gucci, Prada Sunglasses, Dior, Armani and Fendi have their designer sunglasses. Usually it is more expensive that some other sunglasses because they have cost a lot on designing, so if you like fasion and you want to make your self fashionable with sunglasses and you are on good ecnomical condition, I think that will be worthy for you/
I think that depends on your purchasing power, most designer sunglasses have their own mainstream style, take FENDI as an example, their sunglasses always represent youth and fresh. Cucci and D&G are more likely focus on the sophisticated customers, so they provide more solemn and concolorous glasses.
So, if you needn't worry about the money, you can buy designer sunglasses. Otherwise, you can choose other middle price sunglasses, they provide good sunglasses as well.