Lenses Guide.
There are many different categories of lenses. They include:
1. Single vision lenses. They are single prescription generally throughout the lens. They are used for general vision and people wear them all the time. Or specifically for tasks such as reading, driving and using the computer.
2. Bifocals are lenses correcting two types of vision. They can be worn all the time. The top main portion of the lenses corrects the general distance vision. There is a small segment located at the lower third of the lens thar allows clear for near tasks such as reading.
3. Varifocal lenses are a multiple focal lens.
a. There is a gradual change in power throughout the lens. The top part of proportioned for distance, when looking sraight ahead tough the lens. Then beneath this section is the immediate vision portioned used when viewing a computer. Finally, there lower third of the lens is used for reading. You there looking through different parts of the lens to get clarity at different distance.
b. There is no visible segment, so people find this sometimes more cosmetically aesthetic. Also, the gradual power change allows a greater range of clarity at a corresponding range of different distance through a single pair of glasses.
c. There is however some distortion to the vision at the edges of the clear zone that requires getting used to. But there better higher-grade lenses have lower distortions. As well as premium customised lenses that are tailor made to your eye and head movements.