Rigid Gas-Permeable Lenses (RGP)
Rigid Gas Permeable Contact Lenses (RGP) have been available in the United States since 1978, and they are a good option for patients with more complex or difficult prescriptions, or for those who require really precise vision.
Rigid Gas Permeable Contact Lenses were the next advancement in technology after hard contact lenses, and they are made of materials that contain silicone and fluorine. RGP lenses are softer than their original counterparts, but they still hold their shape on the eye. This is why they are called rigid instead of hard.
The special polymer formulations of RGPs make them more permeable to oxygen and make their surfaces less adherent to mucous and protein from the tear film. Their oxygen permeability makes them healthier for the cornea. In fact, they generally allow more oxygen to pass through than even soft contacts. All rigid gas-permeable lenses offer longer lens life and a flexible wearing schedule. Although they have been around longer than soft lenses, the technology that made these improvements possible is new.
Types of RGP Lenses
Rigid gas-permeable lenses go by several other names, including RGP lenses, gas permeable or GP contact lenses, and oxygen permeable lenses.
There are two types of RGP contact lenses: daily wear and extended wear. Daily wear rigid gas-permeable contact lenses are great alternatives for people who cannot achieve their desired visual correction with soft contact lenses. They are also known to pose a lower risk of infection. Daily wear RGP lenses are usually placed in the eyes in the morning and then removed before bed. Extended wear RGP lenses were approved by the FDA in 1987. According to the FDA it is safe to wear this type of contact lens overnight for up to one week. Extended wear lenses are made of special materials that allow overnight wear.
Advantages vs Disadvantages of RGP Lenses
RGP lenses are made of hard plastic that provides crisp vision and corrects most vision problems. They are custom fabricated in virtually any shape so that they can be made to fit even the most difficult and complex cornea. They are durable and have a longer lifespan than soft contact lenses. Like hard lenses, they do require some time to get used to and are not recommended for highly physical activities.
The adjustment period is the main disadvantage of these lenses. Some wearers can adjust to them within a week. For others, it could take up to a month. Another disadvantage is the size of a rigid gas permeable lens compared to a soft lens. RGP lenses are much smaller and are designed to move on the eye when you blink. This increases the risk of dust particles or other debris getting underneath the lens and causing discomfort or possible abrasions to the cornea. Their smaller size can also make it more difficult to wear them during activities such as sports, since they can easily be dislodged from their position.
RGP lens wearers must also commit to a more tedious cleaning and disinfecting routine than soft contact lens wearers. Because these lenses are not to be discarded often (up to one year for some people), they require more care. On the other hand, rigid gas permeable lenses are more resistant to protein deposits, which makes them easier to keep clean. Plus, they come in an extended-wear version that allows a wearer to keep them in their eyes, even overnight, for up to one week.
Are RGP Lenses for Me?
RGP contact lenses are great alternatives for people who have tried soft contact lenses but are not satisfied with their results. RGP lenses are less popular than soft lenses, but they do provide sharper vision for people with astigmatism, nearsightedness, or farsightedness. Good candidates for RGP lenses include people who:
- Can tolerate the adjustment period
- Are unhappy with soft contact lenses
- Can afford cleaning and care expenses
- Need bifocal contact lenses
- Want to reduce their risk of infection
Caring for RGP Lenses
When you receive your rigid gas permeable contact lenses, your eye doctor should give you a set of care instructions. Always follow your doctor’s advice before anyone else’s. Here are some tips to help you care for and maintain your RGP contacts:
- Wash your hands before and after handling your lenses.
- Only use cleaning products recommended by your eye doctor.
- Never share your lenses, even if you are not using them.
- Never top off old solution in a storage case with fresh solution.
- Always keep your storage case clean and sterile.
- Let your lenses air dry before reinserting them.
RGP Lenses Cost
Typically, each RGP lens costs between $30 and $40. Depending on your eye doctor’s recommendations, your level of activity, and how often you replace your lenses, you could own one to five pairs each year. Cleaning solutions and disinfectants can become costly, especially if you wear daily-wear rather than extended-wear. Extended wear contact lenses can be worn for up to one week before cleaning.
You should also consider additional factors such as:
- Your eye doctor’s location
- The type of insurance coverage you have
- Fees for fitting lenses
- Lens brand name/manufacturer
- Follow-up care
- Lens materials and type of lens
RGP Lenses and Orthokeratology
People who are best suited for Orthokeratology (Ortho-k) have nearsightedness less than -4.00 diopters and astigmatism less than -1.50 diopters. Orthokeratology is a great alternative for those who are too young to consider LASIK, those whose prescriptions are continuing to change, and those whose involvement in sports might be limited by wearing contact lenses. It is a non-surgical treatment that uses specially shaped contact lenses to temporarily reshape the cornea in order to eliminate myopia (nearsightedness), so that you can see better at distance without wearing eyeglasses or regular contact lenses throughout the day. Usually the doctor will prescribe specially designed rigid gas permeable (RGP) contact lenses that can gradually alter the shape of the cornea and temporarily eliminate myopia. Ortho-k is safe for people of all ages, as long as their eyes are healthy.
Complications of RGP Lenses
Although there are several benefits associated with rigid gas permeable contact lenses, complications can arise. Such complications include:
- Eyes may become dry at the end of each day
- Costs may be unaffordable
- Adjustment period may take longer than average time
- Abrasions may develop if dust or debris enters eye
- Lenses may get lost due to their smaller size
- May not be as effective as eyeglasses or other forms of vision therapy
Talking to Your Eye Doctor
Here are some questions to ask your eye doctor about rigid gas permeable contact lenses:
- Are RGP lenses available in my prescription?
- Do you think RGP lenses are the best solution for me?
- How long should I expect the adjustment period to be?
- How should I store my lenses when I am not using them?
- Which cleaning products do you recommend for my lenses?
- How much will my lenses cost over time?
- How many follow-up visits do I need to schedule each year?
- If I buy my lenses elsewhere, how much will you charge to fit them?
- What alternatives do I have to RGP lenses?
In 2011, SynergEyes (a contact lens manufacturer in Southern California) introduced a new or second-generation hybrid lens called Duette. The Duette contact lens is designed to correct astigmatism and has a gas permeable center with a silicone hydrogel outer material. This lens is often prescribed to a patient when all other types of lenses fail. They offer greater of oxygen transmission, and fitting is said to be quick and easy. Hybrid lenses are a combination of RGP and soft materials.
- J. Anshel, MD “Smart Medicine for Your Eyes” (SquareOne Publishers, 2011) 332-333
- J. Anshel, MD “Smart Medicine for Your Eyes” (SquareOne Publishers, 2011) 329-330
- GP Contact Lenses, What Are GP Contact Lenses? http://www.contactlenses.org/whatare.htm
- The Journal of the British Contact Lens Association A. Jonathan Jackson, Clive J. Wolsey Contact Lens & Anterior eye – October 2009 (Vol. 32, Issue 5, Pages 204-206, DOI:10.1016/j.clae.2009.06.006)
- J. Weizer, MD; J. Stein MD, MS “Reader’s Digest Guide to Eye Care” (Quantum Publishing Ltd. 2009) 38