I purchased two pairs of clip on shields, one for myself and on for my husband. We both felt the difference immediately upon use. My husband has rarely taken them off his glasses and he says that his eyes do not feel tired, nor does he have the mild headaches which normally occur after a whole day at work on the computer. I only wear glasses for reading but liked the shields so much that I bought the glasses too. My eyes are very sensitive to light and the difference these have made on very bright days when I am indoors has been amazing. I would recommend Ocusheild to everyone. They are well made, reasonably priced and most importantly good for your eyes and overall well-being. Delighted with all products and service, thank you Ocusheild team.