Dear friend, it is hard to follow your question. But finally I guess what you mean possibly is can you use sunglasses as computer glasses to block the reflection and glare from the computer screen. I think you can't use sunglasses as a screen saver. The refection of computer and UV rays are totally different things although both of them can do damage to our eyes. So you should buy a pair of computer glasses. You can have a look on Firmoo for it provides its customers with glasses of great quality and lower price. Hope this can help you.
Oh, I guess what you mean is to use sunglasses to protect your eyes when you are using the computer. I have never tried that. I don't know whether they can work for you. But I think you can have a try. If you found that you can hardly distinguish the letters on the computer screens, you'd better buy a pair of computer glasses. Hope this helped!
Well, if you mean you want to use sunglasses to block reflections and glare of the computer screen, you may turn to the wrong glasses. Computer glasses are used for blocking reflections and glare of computer screens. So you can buy a pair of computer glasses immediately. And apply some artificial tears to lubricate your eyes from time to time if you often use computers for a long time. Good luck!