by Jamie Bartlett December 04, 2019 2 min read
Plano lenses are simply an optical lens which provide no corrective power.
You’ll know if you require plano lenses if you see the term “plano”, “PL” or “0.00” in your Sphere box on your prescription paper. Instead of leaving this initial box blank, it’s common practice for your optometrist to confirm that you require no dioptric correction in that eye.
Right eye | SPH: PL | CYL: 0.00 | AXIS: 000
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Now you think of it, plano is a strange sounding word.
But it derives from the Latin word “planus” for flat or level. In the context of optical lenses, a planoconvex lens refers to a lens which is flat and provides no dioptric power.
For demonstrative purposes in retail or home-trial scenarios, spectacle frames are fitted with what are called demo lenses.
This is done to simulate corrective lenses, simply to give you an idea of what the frame will look like in a more realistic aesthetic.
Despite providing no corrective power, demo lenses are not the same as plano lenses. For display purposes only, demo lenses are cheaply made from thin acrylic and don’t provide any UV or blue light protection for your eyes.
If you prescription requires you to use a plano lens, your glasses will always be fitted with matching quality of lens such as CR39 or polycarbonate. This means your lenses will look and perform the same if you choose to have any additional coatings such as anti-glare, anti-scratch and/or blue light blocking.
Demo lenses are only used for retail purposes to simulate real lenses.
More often than not, one of your eyes will be weaker than the other.
Ocular asymmetry is extremely common therefore you may only require correction in just one eye. However, there are other reasons why plano lenses can be used.
Plano lenses are usually made of a polymer resin called CR39. They are comparably thicker than demo lenses and will usually have additional lens coatings such as anti-glare and anti-scratch. These coatings yield purple and/or green hues when light is reflected from the lens.
Demo lenses are usually made of thin acrylic which is comparably more flexible to the touch. They don’t have any additional lens coatings which produce a plain white reflection. Furthermore, demo lenses are commonly labelled or pad printed with brand name or company information.
Left: Plano lenses with purple and green reflections | Right: demo lenses
Other than retail showroom scenarios, demo lenses aren’t suitable for daily use. They are flimsy, unreliable and provide no ultraviolet or blue light protection for your eyes.
The easiest way to calculate the cost of your prescription lenses is by using our online calculator. There, you can tailor your lenses exactly the way you want them. It’s simple, quick and accurate.
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