My glasses constantly slide and slip. This is a very common problem and is usually due to either worn out frames, a poor lens/frame match in which the lens is to heavy for the frame, or poor frame match for your facial anatomy. Keep in mind too that the back of the ears and sides of the nose are rich in sweat glands which can cause them to slip and slide. Depending upon the reason, several things can be done. A headband might be necessary for heavy glasses when working out in the hot sun. Also, increasing temple support can help greatly. The frames can often be tightened and nose pads added. Worn out frames and delicate frames may need adjusting on a regular basis, and we are happy to provide that service free of charge. Remember too that in the case of plastic frames, being out in the hot sun will cause the frame to stretch out if it’s too large for your face. When all else fails, a new properly fitted feather-weight frame will solve the problem. 2.When I read through my bifoc...