I have heard that some people complain that their sunglasses bring headaches or blurred vision before. But this is the first time I heard that sunglasses can impair our vision. Well, if it is a pair of prescription sunglasses, you can have them checked by an optician to see whether they are of the right degrees in both lenses. Or you can have your eyesight checked again in a morning because the result will be more accurate in the morning than that in the afternoon. Hope this helped!
I strongly suggest you to stop using this pair of sunglasses. You can take the sunglasses back to the eyeglasses store where you buy them. And ask the salesman to prove that whether their sunglasses are with UV protection or not. Besides, they also need to check the degrees in both lenses again because wearing stronger lenses or weaker lenses will cause eye strains or even headaches or vomit. If there is something wrong with the sunglasses, you should ask for a refund or indemnity.
You said that you never had any eye trouble. But this does not mean you will not have any kind of eye troubles in all your life time. I suggest you to schedule an eye exam immediately. The doctors can tell you where the problems lie in. and they can suggest appropriate treatment. If the sunglasses caused the damage, the store should pay for your losses. But if there is some potential eye disease, you must apply some treatment to prevent it from getting worse immediately. Hope this helped!
You'd better have your eyes checked immediately. Sometimes any kind of discomfort can be a starting sign of some kind of eye diseases. It comes across when you wear your sunglasses. But in fact the problems lie in your eyes other than this pair of sunglasses. But if you find that you don't have any problems in your eyes, you can complain it to the sales manager in the eyeglasses store. I think they will find a way to solve your problems. Or you can buy sunglasses in other eyeglasses stores if this store refuses to solve the problem for you.