24/01/2021
In the know:
What are the different types of optical lenses? Part 1
1. SINGLE VISION LENSES
Single vision lenses are the most basic type of lens. Unsurprisingly, they also tend to be the least expensive. Made for correcting one field of vision (near or far), they offer the largest visual field of any lens type.
If you’re only short-sighted or long-sighted, you’ll likely be prescribed single vision lenses.
2. PHOTOCHROMIC (TRANSITION) LENSES
Also known as “transition lenses,” photochromic lenses darken when they come into contact with UV rays. This eliminates the need for sunglasses, increasing convenience and minimising expense for the wearer.
They’re technically not a prescription type, but rather a treatment added to prescription lenses. You can have photochromic bifocals, single vision lenses, and so on.
Note that the lenses will darken even on cloudy days, which some may find inconvenient. However, they’re often a popular choice as they add a little style to your glasses.
3. BIFOCAL AND TRIFOCAL LENSES
You probably remember your grandfather wearing these. This is because these lenses correct a wider range of more severe vision issues. Bifocals and trifocals are lenses that have two and three “powers” apiece, respectively.
They are sometimes referred to as “multifocals” even though this technically refers to progressive lenses.
All within one lens, you have separate sections for near and distance correction, which makes them a versatile choice. Those requiring intermediate vision correction will be prescribed with trifocals that have a third correction too.
The drawback of bifocals and trifocals is that there are lines separating each section, which makes for drastic changes in vision correction when you move your eye inside the lens. It’s something that you learn to work with, but the inconvenience paved the way for advances in lens technology such as progressives.
Source: https://bespokeunit.com/glasses/lenses/