RGP Contact Lenses: Everything You Need to Know

What are Rigid Gas Permeable Contact Lenses?

Rigid gas permeable contact lenses are firm lenses that allow oxygen to pass through the lens material to the cornea. Unlike older hard contact lenses made from PMMA, modern RGP materials are designed to be oxygen permeable. 

RGP lenses are generally smaller than soft contact lenses and typically sit primarily over the cornea. Because the lens retains its shape rather than molding completely to the surface of the eye, the tear layer between the lens and cornea can help create a smoother optical surface. This can provide clear, crisp vision, particularly when the cornea itself has an irregular shape. 

Who Can Benefit from RGP Contact Lenses?

RGP contacts can correct common refractive errors, but they may be particularly useful when conventional soft lenses do not provide the desired vision or fit. Whether they are appropriate depends on your prescription, corneal shape, eye health, comfort, and lifestyle.  

Your optometrist may discuss RGP lenses if you have:

• Astigmatism: Astigmatism occurs when the eye's curvature causes light to focus unevenly. Soft toric lenses work well for many people with astigmatism, but RGP lenses can be another option, particularly with higher or irregular amounts of corneal astigmatism. Because an RGP lens maintains its shape on the eye, it can create a more regular refractive surface. 

• Keratoconus or an Irregular Cornea: Keratoconus causes the cornea to become thinner and develop a more cone-like, irregular shape. As the condition progresses, glasses or conventional soft lenses may no longer provide adequate visual correction. RGP lenses are commonly used to improve vision in people with keratoconus because the rigid lens and tear layer beneath it can mask some of the irregularity of the corneal surface. Carefully fitted specialty lenses can provide substantial improvement in corrected vision for many patients with keratoconus. 

• Higher or More Complex Prescriptions: Some patients with more complex refractive errors may achieve clearer vision with an RGP lens than with a conventional soft contact lens. RGP lenses can also be manufactured in customized designs based on an individual's prescription and corneal shape. 

• Presbyopia: Presbyopia is the gradual loss of near focusing ability that commonly develops with age. Depending on your eyes and vision needs, RGP lenses may be available in multifocal designs or prescribed using other strategies that provide distance and near vision. 

• Difficulty Getting Clear Vision with Soft Contacts: Even without an eye condition such as keratoconus, some people simply do not achieve the clarity they want from soft contacts. If your current lenses fit appropriately but your vision still seems inconsistent or less sharp than expected, a contact lens evaluation can help determine whether another lens design is worth considering. 

RGP Contacts vs. Soft Contact Lenses

Neither RGP nor soft contacts are universally better. The best option depends on the individual wearing them.  

RGP lenses may offer:

• Crisp, stable vision for certain prescriptions 

• Effective correction for some forms of astigmatism and irregular corneas 

• Durable lens materials 

• Less tendency to tear than soft contacts 

• Resistance to some types of deposit buildup 

• Highly customizable lens parameters 

Soft contact lenses may offer:

• Faster initial adaptation 

• A softer feel on the eye 

• Convenient daily disposable options 

• A wide range of prescriptions and replacement schedules 

• Greater familiarity for many contact lens wearers 

It’s important to note that it may take a few weeks to become accustomed to RGP contacts, compared to the typically shorter adaptation period for soft lenses. That adjustment period is important to consider, because someone who wants to wear contacts only occasionally, for example, may have different priorities than someone who plans to wear RGP lenses consistently.

How Are RGP Contact Lenses Prescribed at The EyeDoctors Optometrists?

RGP lenses require more than simply converting your eyeglass prescription into a contact lens prescription. Contact lenses sit directly on the eye, so your doctor must evaluate both your vision correction and how the lens physically fits.  

At The EyeDoctors Optometrists, a contact lens exam includes measurements and evaluations of your corneal curvature, pupil and iris size, tear film health, and vision prescription. Your doctor also evaluates the lens on the eye to make sure it provides appropriate vision and fit.  

For an RGP fitting, the process will include:

• Reviewing your vision and eye health: Your optometrist will consider your prescription, previous contact lens experience, symptoms, eye health, and reasons for considering RGP lenses. 

• Measuring the shape of your cornea: Corneal curvature is an important part of determining the initial lens design. For more complex corneas, additional mapping such as corneal topography may be used when appropriate. 

• Selecting lens parameters: RGP lenses can be customized using factors such as lens curvature, diameter, power, and design. 

• Evaluating a lens on your eye: Your doctor examines how the lens centers and moves and whether it provides clear vision. A slit-lamp microscope may be used to evaluate the fit. 

• Fine-tuning your prescription: The initial lens may require adjustments to achieve the desired combination of fit, vision, and comfort. Specialty contact lens fitting can sometimes require more than one visit. 

• Scheduling follow-up care: Follow-up appointments allow your doctor to check your corneas, evaluate the lenses after you have worn them, and make adjustments when necessary. 

RGP Contact Lens Considerations for Kansas Wearers

Kansas weather can add some practical considerations for any contact lens wearer. Wind, changing humidity, heating and air conditioning, dust, and seasonal outdoor exposure can all affect how comfortable your eyes feel.  

For RGP wearers in Kansas:

• Protect your eyes on windy days. Wind can increase tear evaporation and may blow dust or debris toward the eye. Sunglasses or other protective eyewear can provide an additional barrier when conditions are windy. 

• Pay attention to dryness. Outdoor conditions as well as indoor heating and air conditioning can affect the tear film. If your lenses regularly feel dry, discuss the symptoms with your optometrist rather than relying on random over-the-counter drops. 

• Use only lens-compatible eye drops. Not every eye drop is designed for use with contact lenses. Ask your eye doctor which lubricating drops are appropriate for your particular lenses. 

• Remove a lens if debris gets underneath it. Wash and dry your hands before handling your contacts, then clean and disinfect the lens according to your prescribed care routine before reinserting it. 

• Discuss seasonal irritation with your eye doctor. If pollen, dust, or allergies make contact lens wear uncomfortable at certain times of year, your optometrist can help determine whether the issue is allergies, dry eye, lens fit, or another cause.