Problems With Lined Bifocals

Around the age of 40, many adults with vision problems often find that they're no longer able to refocus their eyes easily to look at objects close to them while they look through their glasses made for long-distance vision. To fix this problem, eye doctors prescribe bifocal lenses that allow you to see close distances clearly through the bottom parts of the lens and long distances through the upper part. For a long time, lined and segmented bifocal lenses originally invented by Benjamin Franklin were the only glasses available to people with this problem. However, progressive lenses are a type of bifocal lens that do not have the lines in them; they look just like single-focus lenses and are often easier to use.

Image Jump

• The lines in bifocal lenses create a drastic jump in focus from one part of the lens to another. If you switch from long-distance to close-up viewing quickly, images sometimes appear to "jump" at you because of the quick, drastic change. Progressive lenses don't have as drastic an effect because they offer a smooth transition from long distance to close viewing instead of an extreme, quick change.

Visible Lines in Lenses

• With traditional bifocal lenses, anyone can easily see that you have a bifocal (or trifocal) prescription. The lines and segments in the lenses are very obvious and easy for others to see. This may or may not matter to you, but some find it cosmetically displeasing to have lines in their glasses that distract from their eyes.

Head Jerk

• Wearers of lined bifocals often find themselves jerking their heads back to look at people or objects as they come closer to them. With lined bifocals, you must either look at objects through your long-distance prescription or your close-up prescription. As objects come closer to you, you'll have to jerk your head to look through the bottom section of your lens to keep the object in focus, especially if it moves quickly. If someone doesn't know you well or understand how bifocals work, they may find this behavior strange or offensive. Non-lined bifocals, on the other hand, give you a transition section between your two prescriptions so you won't have to jerk your head as drastically.

Reflected Images

• Some bifocal wearers experience a reflected or upside down image due to the bifocal lines. This can be fixed by your optician by adjusting the height of the bifocal or by using an anti-reflection coating, but can be incredibly annoying until you're able to get it fixed.

Choosing Frames

• Any type of bifocal or multi-focal lens requires a certain amount of space to create the transition between one focal distance and another, while giving you enough space in each focal section to look through. This is true of both lined and progressive lenses. If you're choosing a new frame, you'll need to keep this in mind, and you may not be able to get your first choice in frames, depending on your personal style. The good news is that advancing technology is allowing multi-focal lens wearers to choose slimmer and smaller lenses, but ask your eye doctor for guidance when picking a frame if you're unsure. Choose a frame with adjustable nose pads to help your transition into a new frame, especially if you're new to bifocals. Once you choose your frame, the doctor will measure your eyes and craft the lenses that go into it to fit your eyes and face.