A varifocal lens is actually 2 lenses in one piece of material.

Choosing a lens can actually be quite complicated, and you might want to do a bit of reading before choosing your lens to make sure you get a varifocal that works really well for you.

Below is a summary of the key things that you need to consider about your varifocal glasses.

Thickness of the lens. Standard varifocals which are the cheapest are also the thickest. You can often get premium varifocals (thinner) which have a 1.6 rating or super-premium lenses (thinnest - 1.74 rated). Expect to pay 2 to 3 times more for the very thinnest lenses available. Many opticians are not able to supply the 1.74 rating.

• Coatings. You should be able to have coatings such as scratch resistance and tinting applied to most varifocals. In some cases, ultra-premium 1.67 and 1.74 rated lenses cannot be coated as an option but have scratch protection already applied.
• Vision corridor. If this sounds a bit techy don't worry. Basically varifocal lenses need a distance to change from far sight corretion to near sight correction. Normally this distance is 21mm which means that you can't use varifocal lenses in the smaller frame styles. However you can also get short corridor lenses which allow for this. Short corridor varifocal lenses are often much more expensive than the standard equivalents.