Single vision glasses contain only one prescription power, meaning they will correct the vision of either nearsighted or farsighted wearers, but not both. Progressive glasses, on the other hand, contain three different prescription powers in one pair of glasses– near, intermediate, and far distance. This makes them extremely convenient for glasses wearers who need vision correction at both near and far distances and don’t want to carry around multiple pairs of glasses.
Because the entire lens in a pair of single vision glasses is dedicated to just one prescription power, wearers enjoy a wide range of vision– through the entire prescription lens. Progressive lenses offer wearers the convenience of three glasses in one, but the sides of the lenses are blurry, thanks to the seamless shift between prescription powers in the viewing areas.
One of the most significant differences between single vision and progressive glasses is that there is no adjustment period associated with new single vision glasses. Wearers of progressive glasses go through an adjustment period with every new pair. This adjustment period is the time it takes the eyes to learn how to use the different parts of the lenses to see at different distances. It can take a few weeks to adjust, and some people find that they are never able to get comfortable with progressive lenses.
Generally speaking, progressive lenses have been considerably more expensive than single-vision glasses, due to containing three different powers of vision correction. While our progressive lenses may cost a little more than our single-vision, they are still a small fraction of what you would pay elsewhere.
Both bifocal and progressive reading glasses are considered multifocal lenses because they both offer more than one prescription power in one pair of glasses. However, despite this similarity, they are quite different from one another.
The lenses in bifocal glasses have two viewing sections: a larger, upper lens for distance viewing, and a smaller, lower lens for reading. There is a visible line where these lenses meet. Progressive lenses offer three viewing sections: a primary lens for distance viewing, a very slender midsection for intermediate distance vision correction, and a lower section for reading.
Unlike bifocal lenses, there is no visible line between the prescription lenses in progressive reading glasses. While this gives them a far more subtle appearance, it also creates a blurry section on the sides of the lenses, which can take some getting used to. Some people prefer bifocal glasses because there is no blurriness in the lenses, and consequently a wider line of sight.
The line between prescription powers in bifocals also contributes to an abrupt shift between magnifications that can be disorienting to bifocal wearers, especially on stairs. While progressive lenses don’t have such a dramatic shift between powers, it still takes a while for the eyes to adjust to a new pair of progressive reading glasses.
The middle distance visual correction offered by progressive lenses is a significant bonus for glasses wearers who use computers frequently. While bifocals are ideal for folks who need both distance and close-up vision correction, progressive glasses are a better option for those who frequently need middle-distance visual clarity.
No-line bifocals and progressive glasses are the same things! While the term “no-line bifocals” gets tossed around quite a bit, this is just another way of describing progressive glasses. If it helps you to visualize the difference between bifocal and progressive glasses, think of bifocals as two steps and progressives as a ramp.