What Are GP Contact Lenses?
GP contact lenses often provide superior vision and better value.
More than 37 million Americans wear contact lenses, yet many people are unfamiliar with GP contact lenses.
In 2012, GP contact lenses accounted for about 9% of all new contact lens fits and refits in the United States.* GPs are a high-tech, growing alternative to soft contact lenses.
There are three types of contact lens materials:
- Hard (PMMA) lenses, the original type of contact lens, now virtually obsolete
- GP contact lenses (primarily made from fluorosilicone acrylate, introduced in 1987)
- Soft lenses, made from gel-like plastic, first marketed in 1971
GP contact lenses are also known as rigid gas permeables, or RGPs. Your eye doctor may call them GPs or RGPs.
GP contacts are made of a firm, durable plastic that transmits oxygen. They offer excellent eye health: because they don't contain water like soft lenses do, they resist deposits and are less likely than soft contacts to harbor bacteria.
GP contact lenses clean and disinfect easily, don't dehydrate, are easier to handle, and last longer than soft lenses.
And since GP contacts retain their shape better, they provide crisper vision than soft contact lenses. [Read more about GPs vs. soft lenses.]
Why Are GP Lenses So Comfortable?
GP lenses are not the same as the old hard lenses. For one thing, GP lens materials allow oxygen to pass through the lens and reach your cornea. Hard lenses are not oxygen permeable.
Watch an informational video about GP lenses shown on PBS television stations.
Secondly, GP contact lenses are custom made for each individual. Your eye care practitioner will measure the exact shape of your cornea and prescribe lenses with the curvature, size, and corrective power that suit your particular eyes.
With advances in manufacturing, GP lenses are made in thinner designs, larger diameters, and with more consistently smooth edges than ever before. As well, more eye care practitioners are using sophisticated techniques to map eye topography, enabling the back surface of the lens to better align with the cornea.
All these changes result in lenses that center well on the eye, providing good comfort and crisp vision.
The Truth About Contact Lens Comfort
People sometimes mistakenly infer that a "soft" lens will be comfortable, but a "rigid" lens will not. In fact, both soft and GP lenses can provide long-term comfort.
However, soft lenses do provide better initial comfort, while GP lenses require a brief adaptation period. But this is due to the size of the lens not the lens material.
Soft lenses are larger in diameter than GP lenses and "tuck under" the eyelids. As a result, you don't feel the lens edges when you blink. But since GP lenses are smaller, during blinking your eyelids will experience initial "lens awareness."
Your lids gradually adapt so that you don't feel the lens with each blink. Once over that small hurdle, the comfort of soft and GP contacts can be comparable.
Think of it like getting a new pair of shoes. You may "feel" the shoes while you break them in, but if they're the proper fit, that feeling disappears. Shoes don't have to be made of gel to be comfortable, and neither do contact lenses.
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*Source: Contact Lens Spectrum, January 2013.
[Page updated February 2013]