Making Glasses Thinner
Dr. Langford October 25th, 2006
If your glasses prescription is like mine, then you realize how thick the edge of a lens can be. People who order their glasses in regular plastic (CR-39 polymer) are often disappointed because the edge is much thicker than they had hoped.
The optical industry has largely switched to polycarbonate, which offers increased safety as well as being thinner than plastic for the same power in a prescription. Until recently, the minimum center thickness for polycarbonate was 1.5 mm. For nearsighted prescriptions, the outer lens edge is thicker than the center. Now days, we can get “dress” (as opposed to safety) spectacle lenses in 1.0 mm center thickness (CT). This translates into much improved thinness to the lens edge.
Take a look at this picture.
These two lenses are the same power, a very mild nearsighted prescription. The new lens mounted in the frame is a 1.0 CT polycarbonate while the old lens being held is 1.5 CT polycarbonate. Despite being a very mild Rx, the edge thickness is noticeably different between 1.0 and 1.5 CT poly. Imagine the difference if your nearsightedness is moderate to high!
Another way to make the edge appear thinner is our roll and polish option. This option is actually a free upgrade if you purchase one of our select lens packages.
Those of us with moderately high prescriptions (4-5) should consider upgrading to the 1.67 High Index Material and those with high prescriptions should strongly consider upgrading to the 1.74 Ultra High Index material. These high index materials make the lens edge even thinner than the 1.0 CT Polycarbonate.
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