Bifocal lens is a lens that allows you to see two distances: far and near only!
It is suitable for people who are starting to experience presbyopia and don’t want to keep putting on and taking off their glasses all the time.
The way to use bifocal glasses is, when you look straight ahead, you will be using the distance vision zone. However, if you slightly glance down towards the bottom of the lens, you will be using the near vision zone.
Bifocal lenses come in 3 types:
- Round style – The near vision zone at the bottom of the lens is shaped like a circle.
- Half-moon style – The near vision zone is shaped like a half-circle, covering only part of the lower lens area.
- Flat-top style – The lens is divided evenly between the distance and near vision zones.
Advantages
- More affordable than progressive lenses
- Relatively wide field of view
Disadvantages
- The mid-range vision zone is missing
- Looking down at the near vision zone may cause image jumping, making it uncomfortable for the eyes
- The lens is not aesthetically pleasing because it’s not smooth and seamless, with visible lines where the zones meet