I had to use a knife to aggressively shave off about 1 mm on each side of the nose area of the lens before it would pop into the frame. I then had to heat the wings and bend them out so I would not get a headache with them squeezing the sides of my head. After all of that, which took more than an hour, I am pleased with the result but I will not attempt to exchange lenses. I feel that either the frames or the lenses were not manufactured to adequate tolerance. That said, it seems like a quality product for the money. If you take the time to make the adjustments I feel you will be pleased.