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Rigid gas permeable (RGP) Contacts

Rigid gas permeable contacts are also known as RGPs, gas permeable (GPs) or oxygen permeable (OP's). They are worn by around 15% of people who wear contacts and cover 2/3 of the cornea. They are made of a plastic that is firm and durable plastic, transmits oxygen well and don't contain water. Many vision care specialists recommend gas permeable contacts because they have certain advantages.

The following are some of the reasons cited by professionals for why gas permeable contacts are better. (These views don't necessarily reflect the views of this site.)

Resist Deposits: Rigid gas permeable contacts have a finish that is smooth and slick so that protein and bacteria cannot stick or build up them as easily. This can make them more comfortable and healthier to wear.

Easier to Take Care of: Since they don't get stuff built up on them as easily it can make it easier to clean and disinfect them. Also since they are made from a firmer plastic they don't scratch or tear.

Less Water: Since they have a low water concentration they don't dehydrate easily, which means they won't pull water away from your eyes either.

Last Longer: They tend to last longer because they are made of a more durable plastic and don't tear easily.

Easier to Handle: Since they are more rigid is shape many people think they are easier to handle than soft lenses.

Better, Crisper Vision: The optics are better with rigid gas permeable contacts, since they retain their shape better.

Astigmatism They are espcially good for people with corneal astigmatism.

Oxygen Transmission: They let in a lot of oxygen, which is healthier for your eyes too.

May slow progression of myopia - Some studies have shown that gas permeable can sometimes slow down the progression of nearsightedness (myopia), unlike glasses or soft contacts, especially in teenagers.

Possible disadvantages of gas permeable contacts:

- They take longer for your eyes to get used to.

- Not disposable. Many people claim the fact that they last longer and don't need to be replaced as often as an advantage, but this could just as easily be seen as a disadvantage. I personally find it much more convenient to throw contacts away and wear new ones, rather than having to clean them all the time.

- More difficult to handle. Rigid contacts may not tear easily, but could be crushed.

- Higher cost - individually these contacts cost more, which might be ok since they can last a long time, but if you lose or break one, it will cost more to replace than a typical disposable soft contact.

- Individually Fit - they have to be custom made for each person after and eye doctor measures your eye very precisely.

Some Common Brands of Gas Permeable Contacts

Since all gas permeable contacts are custom made to fit each person, they don't come in a set list of power, base curves or diameter like soft contacts. The following are some of the brands available:

Boston Envision - these are made by Bausch & Lomb and are made with a patented non stick surface so that stuff can't stick to them easily.

Boston MultiVision - These are also made by Bausch & Lomb and are for people with presbyopia. Great for distance, intermediate, and near vision. Made from Boston ES material. (And what is Boston ES material, I don't know they don't say on their site.)

Menicon Made from tisilfocon A and are 30 day of extended wear contacts.

Fluoroperm 30 - couldn't find any more information about these lenses.

Paragon HDS - couldn't find any more information about these lenses either.

It seems the gas permeable proponents are quick to disperse information about how great the contacts are supposed to be. However they seem to be lacking in marketing skills - as I have had a difficult time even finding information about the different brands available. Muchless able to find any detailed information about them. Nevertheless, here are a couple more web sites with general information about gas permeable contacts:

All About GP Lenses: This site was put together by the Contact Lens Manufacturers Association.

Rigid gas permeables - from the site 'Refractive Source' created by Brian Chou, O.D., F.A.A.O. - a San Diego optometrist.

Other articles in this series are: Contacts - An Introduction Part I: Eyes and Vision,
Contacts - An Introduction Part II: Contact Types and History,
Soft Contacts - Daily Wear and Disposable,
Daily Wear Contacts,
Extended Wear Contacts and
Orthokeratology.