RGP Contact Lenses

Rigid Gas Permeable Lenses

Today's hard contact lenses are known as RGP (rigid gas permeable) lenses. While anyone can wear RGP contact lenses, they are especially valuable for individuals with high levels of astigmatism who are unable to wear toric contact lenses.

The hardness of RGP lenses makes them much more durable than soft contact lenses and they will therefore last longer. While RGP lenses may seem more expensive in the short term, this longer replacement schedule makes the long-term costs lower.

RGP contact lenses essentially 'mask' the eye's normal shape. A tear layer forms underneath the contact lens such that no matter how high your astigmatism or spherical prescription, you will enjoy crisp, clear vision because it's the contact lens which determines how light enters the front part of the eye. This is why RGP lenses generally allow you to reach greater acuity than with soft contact lenses.

RGP lenses cover only the very front part of the cornea (the clear part of the eye) and are designed to remain in place even when you blink. For this reason it's very important they be extremely efficient at passing oxygen to the eye, hence the name "gas permeable," meaning that gases (ie. oxygen) are allowed to pass freely through the contact lens and into the eye. This permeability is the reason RGP contact lenses of today excel over the hard lenses of yesterday. The hard lenses of yesterday were made of a material called PMMA, which was terrible at transmitting oxygen - a very necessary ingredient for healthy eyes. New material containing silicone allows today's RGP lenses to transmit more oxygen than even soft contact lenses.

Despite the benefits of RGP contact lenses, you'll likely find very few people actually wear them. All you have to do is try them on to find out why. Because RGP lenses are hard, they do not mould themselves to your eye and are very difficult to become accustomed to. It takes time for your eyes to adapt. Also, you will find that should you decide to stop wearing the lenses for even as short as a week, you will again need to adapt before they become comfortable again. RGP lenses require regular wear. Despite this initial adjustment period, many wearers of RGP lenses swear by them and would recommend them to anyone.