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About Lens Thickness

The stronger the prescription, the thicker the lens required. Fortunately, today there is a variety of plastic lens material that has been created to bend light more efficiently than conventional plastic lenses. This means less material is required to correct your vision. Less material means thinner and lighter lenses for you. There are many choices when it comes to high index lenses.

Comfort Sight standard spectacle lenses are standard "CR39" 1.56 index optical plastic lenses. The 1.56 index refers to the lens thickness and is also known as the refractive index. Generally the higher the refractive index, the thinner the lenses.

For prescriptions up to + or – 2.00, we recommend 1.56 Mid-High Index Lenses (22% thinner than standard prescription lenses).

For prescriptions up to + or – 3.00 we recommend thin 1.60 High Index Lenses (up to 30% thinner than standard spectacle lenses).

For prescriptions up to + or – 4.00 we recommend extra-thin 1.67 Super High Index Lenses which can reduce thickness by up to 40%.

For prescriptions over + or – 4.00 we recommend ultra-thin 1.74 Ultra High Index Lenses which can reduce thickness by up to 50%.

For rimless glasses we do not recommend standard CR39 lenses as it is not strong enough to withstand the extra pressure. We recommend 1.6 index lenses for rimless frames as it is made of “MR8” material. It has excellent impact resistance, excellent optical quality, excellent process ability, excellent lens design flexibility and high refractive index. Thinner lenses also look much better and they are lighter, especially at such a high prescription.

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