subject: Varifocal Glases - A Guide For Buyers [print this page] If you have problems with both short-sightedness and long-sightedness then varifocal glasses might be the thing for you.
Varifocals contain two sight corrections in one lens, one for your short-sighted vision and one for the long-sightedness. Before varifocals, getting 2 sight corrections in a single lens required bifocal glasses. Bifocal glassse are a short-sight correction lens, that has a distinct long-sight correction lens contained in a little area at the bottom of the lens. This solution is not ideal though, as to get your long-sight correction you have to carefully look through a small lens area in the lower half of the lens. Also, these glasses often look unattractive.
For the wearer, the prescription of the varifocal lens varies gradually starting at the top and moving gradually to the bottom of the lens. As a result near sight tasks such as reading a newspaper the wearer merely looks through the lower part of the lens. For long-distance tasks including driving, you simply look through the top part of the lens.Varifocal lenses can now be fitted in most of glasses frames on the market, though there are a few things to bear in mind.
The main difficulty often is the size of the frame. In order to fit two lenses within a single frame, there is a need for the lens to have adequate height to enable the prescription to change. There are ways around this though. The majority of varifocal prescription glasses need a height of 25mm minimum so as to operate correctly. Now though, you may choose short corridor varifocal lenses that can be housed in frames less than 25mm high, and even as small as 13mm.
You can also choose from a variety of lens thicknesses. For stronger prescriptions the lenses in standard varifocal glasses tend to be relatively thick which many wearers find unsightly. For occasional wear, this doesn't particularly matter, but if the glasses are your main pair, you may consider one of the thinner options. A standard, thinner varifocal lens is the 1.6 option. For ultra-thin, you can choose a 1.67 premium varifocal lens. Finally, if you need the absolute thinnest lens currently available you may wish to try the 1.74 grade. As you might expect, the thinner the lens, the the more you will pay, so it's well worth giving some thought if you actually must spend the extra money.
As with other types of glasses, coatings are available for varifocal lenses including scratch protection, anti-glare coatings, and sunglasses tinting. As varifocal lenses are usually a factory order, not all coatings are available on all lenses. This might again influence your choice as to which lens option to select, depending on your requirements.
To order varifocal glasses online a prescription is needed from an opticians. As well as the standard prescription details there are some extra particulars that will be needed.
Specifically, you will need the pupillary distance. This is a distance in millimeters from one pupil to the other. This should ideally be measured by an optician, although if required you can do it at home by using a ruler and the assistance of a friend.
Varifocal glasses, are a great step forward in improving the vision and looks of anyone with both long and short-sightedness. Now they are available online, less costly and easier than ever before, so why wait. Make your world a little clearer today.
by: Dave Smith
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