My first pair of progressives it took me a couple of weeks to adjust...felt slightly nauseous during that time. But, I stuck with it, and now it's no problem at all. Each "new" pair since then, of course, is slightly different than the prior pair, so there is a small adjustment period till they feel "normal" to me. Maybe a couple of days? My sunglasses and regular glasses are both from Costco, with the same prescription. They give you $30-40 off, depending on the special they are running, on the second pair. I was out the door for $350, both pairs. Great price! I've paid that much WITH insurance benefits for a single pair somewhere else. Grrrrr. I love their flat pricing...not extra for this coating or that, etc.