Most individuals adjust to them in a week or two, although it might take longer. Some people dislike the changes in eyesight and abandon bifocals or progressives. You may experience hazy eyesight at first. This will go away in time. Progressive lenses are more difficult to get used to than single vision lenses because they require you to bend your eye to see through the lens on the outside corner of your eye. Until you get used to this new way of looking at things, others will have to wait for you to stop reading books from cover to cover! The advantage of progressive lenses is that they allow you to see objects up close and far away at the same time. With single vision lenses, you must choose one distance at which to focus, usually close-up work or far away scenes. Not only does this make what you're doing easier, it also gives you a better view of the world around you. Individuals who wear bifocals often complain about the strain this places on their eyes. The problem with bifocals is that they only provide split vision - half of your vision is covered by each lens. This means that you can only use your sight effectively for so long before you have to rest your eyes.