Are you currently wearing 2 separate glasses, one for distance one for reading? Have you heard of bifocals or varifocals? There are a number of different lens types on the market, below we will discuss the options available to you so you can decide to best option for your lifestyle needs.
Single vision lenses
This type of lens contains one prescription which covers the entire lens. This is often used by people that are short sighted or long sighted, and are able to see near and far with one prescription. It can also be used by people to make up distance glasses to do distance task such as driving or made up with a near prescription to allow for close tasks such as reading.
This is an option for people that have 2 prescriptions, one for distance and one for reading. When people require 2 prescriptions it means that the eyes aren’t able to focus at different lengths with a single vision prescription. This is called presbyopia which is a normal ageing process of the eye.
Bifocals are lenses that are divided into 2. Usually the top would be for distance and the bottom would be for reading. Bifocals are ideal as it is a lot more convenient than switching and swapping glasses for different tasks. For example they allow you to watch TV in the distance but also look near at the remote to see the buttons.
Bifocal come in different shapes and sizes, the most common type is a D-shaped segment which allows for a good reading area but also good peripheral vision
Varifocal lenses are lenses which contain 3 vision types; distance, intermediate and reading. They work by changing power progressively from the top of the lens to the bottom. Moving your eyes to look through different parts of the lens gives you clear vision at the distance you need.
The main benefit of varifocals over bifocals is that bifocals contain only distance and reading, which means tasks such as computer use can become difficult. Varifocals are ideal in office environments or working in retail as they allow you to use computers as well as other tasks.
Cosmetically they also look better than bifocals as they have no visible line which means that they look like ordinary single vision lenses.
Varifocals are available in different levels with some more expensive than others. The main downside of varifocals is that they have "soft focus" edges. This simply means there is an element of peripheral distortion due to the way the lenses are designed. This is only noticeable when looking through the edge of the lenses.
Typically better varifocals lenses cost more as they reduce the amount of soft focus present, which in turn gives a wider corridor of clear vision.
Occupations/office lenses are graduated lenses that are designed for intermediate and reading distances. They are ideal for people that are often staring at computers for long periods of time. They are generally better than varifocals for computer use as they have a wider visual corridor for intermediate distances. The main limitation of occupational lenses is that you are unable to walk around with them so they are purely used for when doing near/intermediate tasks.