Single Vision lenses are the optical industry’s standard for the majority of prescriptions. It is the most basic type of lens for glasses where the whole lens is made to the same prescription. For younger patients this allows clear vision at all distances. However, when people reach approximately the age of 45, a condition called presbyopia occurs to such an extent that separate prescriptions are often needed for long and short distances. This means either two separate pairs of glasses, or a switch to Bifocal or Varifocal lenses.
A Bifocal lens consists of two parts. An upper part for clear long distance vision (walking, driving, TV etc), and a lower section (usually in a circular or half-moon shape called a D segment) which is stronger and allows the eye to focus closer up. The bifocal D segment offers a distinct reading segment up to about a third of the lens height from its base. These lenses give nice wide viewing areas for both long-distance and close-up, but it might not be easy to focus on middle-distance items, for example computer screens and music stands. Solutions for this include having a separate pair of computer glasses, or using Varifocals.
If you require bifocal eyewear for a particular purpose such as reading, or riding a motorbike, then please let us know at eyekit.co by adding your requirement to the additional details section of the prescription input page. We will then set the lower half moon segment to optimise vision for that purpose. Should you wish for the segment to be positioned at a particular height then please state this on the additional information box instead.
Varifocals are lenses that combine your distance, reading and intermediate prescriptions into one lens. However, they provide clear vision at all distances, at the expense of some field (or width) of view for reading. They do not have any dividing line, so look just like a standard pair of lenses. Varifocal lenses have some slight distortion on the lenses because of the way they are made. This means you have to move your head more when using Varifocals to avoid catching some of the distorted areas. The better the quality of the varifocal the less distortions you will notice. We do not currently have any varifocals set up on our system as there are a huge range of options that are better discussed. If you require varifocals either email us at email@example.com with your prescription, the prescription package you require and your intended us for them and we will email you back prices and options. Alternatively if you are not sure of your requirement, just give us a call and we can take you through the options. There are so many types of varifocals now that can be tailored to your requirements it is better to spend a little time determining what is best for you.