Quick facts
- "Gas permeable lens" means rigid, not soft. A rigid gas permeable (RGP) lens holds its own shape on the eye, transmits oxygen through the polymer rather than through water, and is fitted against a corneal topography map rather than a single keratometry reading.
- The United States splits the class by wearing schedule. 21 CFR 886.5916 places a rigid gas permeable contact lens in Class II if it is intended for daily wear only and Class III if it is intended for extended wear — the same lens material, two different premarket routes.
- Canada separates the lens from the care product and licenses both by derived class. There is no Canadian entry naming an RGP lens; the lens takes its class from the rules in the Medical Devices Regulations, and the care product that accompanies it is classified separately.
- Care products have their own US entries. 21 CFR 886.5918 covers rigid gas permeable contact lens care products, and 21 CFR 886.5928 covers soft lens care products — so a clinic that stocks both lines is stocking two regulated categories, not one.
- The United States has a federal prescription-release rule. The FTC Contact Lens Rule governs how a contact lens prescription is released to the patient and to a seller the patient authorises; there is no matching federal instrument in Canada, where the obligation sits with the provincial regulator.
- Tolerances are standardised, not negotiated. The ISO 18369 series covers vocabulary, tolerances and measurement methods for contact lenses, which is why a fitting that works with one laboratory's lens can be reproduced with another's.
Rigid gas permeable lenses sit at an awkward point in a supply conversation. They are medically prescribed, they are fitted by a professional, and they are also a repeat consumable — which means the same clinic is dealing with a device classification question, a fitting question and a reorder question at the same time.
This article sets out what an RGP lens is, how each country classifies the lens and its care products, how the fitting is documented, what the prescription-release rules require on each side of the border, and which supplies a lens-fitting lane actually consumes.
What is a gas permeable lens, and who is it fitted to?
A gas permeable lens is a rigid lens made from a polymer that transmits oxygen. The distinction that matters clinically is not oxygen alone but rigidity: a rigid lens can neutralise irregular corneal astigmatism that a soft lens drapes over and follows.
That property drives the fitting indications:
- Keratoconus and other ectatic disease, where the cornea is irregular and the lens has to restore a regular refracting surface.
- High or irregular astigmatism, where a soft toric lens either rotates or cannot fully correct the cylinder.
- Post-surgical or post-transplant corneas, where the topography is not rotationally symmetric.
- Paediatric and young adult cases where a stable, durable lens is preferred for the daily routine of insertion and removal.
The counterweight is the adaptation period. A rigid lens is felt on the lid margin for the first days, and the fitting has to be reviewed after the lens has been worn long enough for the tear film and the lid to settle. That review is a scheduled appointment, not an optional one, and it is the point at which most fittings are refined.
How does each country classify the lens and its care products?
The lens and the solution that keeps it clean are two regulated categories, and the United States writes the wearing schedule into the classification itself.
| Item | Canada | United States |
|---|---|---|
| Named entry for a rigid gas permeable lens | None; class derived from the rules | 21 CFR 886.5916, rigid gas permeable contact lens |
| Class for daily wear | Derived (Class I to IV by rule) | Class II |
| Class for extended wear | Derived (Class I to IV by rule) | Class III |
| Named entry for RGP care products | None; class derived from the rules | 21 CFR 886.5918, rigid gas permeable lens care products |
| Named entry for soft lens care products | None; class derived from the rules | 21 CFR 886.5928, soft lens care products |
| Premarket route in practice | Device licence where the derived class requires it | Premarket notification, or a premarket approval for Class III |
| Who may place a prescription lens on a patient | The fitting professional, under provincial rules | The fitting professional, under state rules |
Two points are worth keeping from this table. First, the wearing schedule is a regulatory variable in the United States, not only a clinical preference: daily wear and extended wear sit in different classes with different premarket routes, so a clinic that changes a patient to extended wear is changing the regulatory position of the product in that patient's eye. Second, Canada derives the class from the rules in the Medical Devices Regulations rather than from a name, so the questions a Canadian buyer asks are about the device licence behind the product and the establishment licence of the party importing it.
How is the fitting documented?
Both countries treat the fitting as a professional act recorded in the patient record, and the record has to survive a change of practitioner, laboratory or lens design.
The elements that make a fitting reproducible are the same on both sides of the border:
- Topography and refraction at the baseline visit, so that a later change in the lens can be compared with the cornea rather than with a memory.
- The lens parameters as ordered — base curve, diameter, power, material, and the design name — because a reorder that quotes only power is not a reorder of the same lens.
- Wearing time and comfort at each review, since the review interval is what determines whether the next lens is a refit or a repeat.
- The care regimen prescribed, including whether the patient uses a rigid-lens product rather than a soft-lens multipurpose solution, which is the compliance failure that shows up most often in practice.
- The prescription itself and its expiry, because in the United States the practice has a defined obligation to release it.
| Record element | Why it matters at the next visit | Where the requirement sits |
|---|---|---|
| Baseline topography and refraction | Separates a lens problem from a cornea problem | Professional standard of practice |
| Ordered lens parameters | A reorder quoting power only is not the same lens | Practice record policy |
| Wearing time and comfort | Decides between a refit and a repeat order | Professional standard of practice |
| Prescribed care regimen | Rigid and soft care products are separate lines | Product instructions and college guidance |
| Prescription and expiry | Release is a defined step in the United States | FTC Contact Lens Rule; provincial college |
The College of Optometrists of Ontario regulates optometrists in the province and sets out the fitting expectations that sit behind the record requirements for Ontario practices, while the Canadian Association of Optometrists publishes the patient-facing library that clinics draw on. Comparable state-level rules apply on the US side, which is why a template record cannot simply be exported from one jurisdiction to the other.
What does the US prescription-release rule require, and what applies in Canada?
This is the clearest divergence between the two markets, and it is a federal rule in one country and a provincial obligation in the other.
In the United States, the FTC Contact Lens Rule governs the release of a contact lens prescription. In outline, the prescriber must give the patient a copy of the prescription and must provide or verify that prescription for a seller the patient has authorised. The practical effect on a practice is procedural: prescription release is a defined step with a defined output, and a patient who asks for the prescription is exercising a right, not making a request.
In Canada there is no equivalent federal instrument. The obligation to release and to document sits with the provincial regulator through its standards of practice and its code of ethics, and enforcement runs through the college rather than through a federal trade rule. For a group practice operating on both sides of the border, the difference is operationally real: the US side has a federal release procedure, and the Canadian side has a college expectation that has to be read province by province.
Which supplies does a lens-fitting lane consume?
The lane consumes three groups of items, and only the first of them is the lens.
- Lens handling and hygiene. Nitrile examination gloves are worn at every insertion and removal taught in the clinic, and cleaning cloths and lint-free wipes are consumed at every teaching appointment.
- Lane surfaces and patient contact. Exam table paper is changed between patients on the examination unit, and disposable tongue depressors and swabs are used in the external eye examination that precedes a fitting.
- Protection for staff working close to the face. A clear anti-fog face shield is the practical item where a clinician leans in close for slit-lamp and insertion work.
A useful way to buy for this lane is to separate the prescription items from the disposable items on the order sheet. The lens itself is ordered against a prescription with parameters; the tray paper, gloves, swabs and shields are reorder-stock consumables with a usage rate, and mixing the two into one list is what produces the familiar problem of stockouts in the disposable lines during a busy fitting week.
Sources
- 21 CFR 886.5916, rigid gas permeable contact lens
- 21 CFR 886.5918, rigid gas permeable contact lens care products
- 21 CFR 886.5925, soft (hydrophilic) contact lens
- 21 CFR 886.5928, soft (hydrophilic) contact lens care products
- 21 CFR 886.9, limitations of exemptions from section 510(k)
- 21 CFR 886.1760, ophthalmic refractometer
- 21 CFR 886.1570, ophthalmoscope
- FTC Contact Lens Rule
- ISO 18369-1:2017, contact lens vocabulary, classification and tolerances
- ISO 18369-2:2017, contact lens tolerances
- ISO 18369-3:2017, contact lens measurement methods
- ISO 15004-1:2020, ophthalmic instruments, fundamental requirements
- College of Optometrists of Ontario
- Canadian Association of Optometrists, eye health library
- College of Optometrists of Ontario, funding for eye examinations
- Ontario, what OHIP covers
- Canadian Association of Optometrists, amblyopia resource library
- American Academy of Ophthalmology, contact lens care
- American Optometric Association, contact lens care
- American Academy of Ophthalmology, how often to have an eye exam
- Medical Devices Regulations, SOR/98-282
- World Health Organization, blindness and visual impairment
Ordering for an optometry group, ophthalmology practice or multi-site clinic? Wholesale and multi-site ordering covers account setup and case pricing, and the B2B wholesale collection lists the lines stocked for institutional buyers. Practices that also reprocess instruments can start with the biological indicator 5-pack trial and read the sterilization monitoring collection for the monitoring lines.
Related reading
- Contact lens solutions in Canada vs the US: which rules apply
- Snellen charts and eye test charts in Canada vs the US: which scale is used
- Ophthalmic eye shields in Canada vs the US: which device rules apply
- Comprehensive eye check-ups in Canada vs the US: which exam interval applies
Frequently Asked Questions
Is a gas permeable lens the same as a hard contact lens?
It is the modern form of one. A gas permeable lens is rigid, but it is made from a polymer that transmits oxygen, which is the difference from the older non-permeable hard lenses. In practice the term rigid gas permeable is used for the current generation, and the fitting indications are irregular or high astigmatism, keratoconus and other ectatic conditions, and post-surgical corneas where a soft lens cannot fully correct the surface.
Why does the US class a rigid gas permeable lens differently for daily and extended wear?
Because 21 CFR 886.5916 writes the wearing schedule into the classification: Class II if the device is intended for daily wear only, and Class III if it is intended for extended wear. The lens material may be identical; what changes is the intended wearing schedule and therefore the premarket route the manufacturer has to take.
Does Canada have an equivalent entry for an RGP lens?
No. The Medical Devices Regulations do not name a rigid gas permeable lens, so the class is derived from the rules in the regulations and the licence obligation follows from that class. The practical check for a Canadian buyer is the device licence behind the product and the establishment licence held by the party importing or distributing it.
What does the FTC Contact Lens Rule require of a prescriber?
In the United States the Contact Lens Rule governs prescription release. The prescriber must give the patient a copy of the contact lens prescription and must provide or verify the prescription for a seller the patient has authorised. The effect in a practice is procedural: release is a defined step with a defined output rather than a discretionary courtesy.
Is there a federal prescription-release rule in Canada?
No. Prescription release in Canada is a provincial obligation that sits with the college through its standards of practice rather than with a federal trade rule. For a group operating in both countries that means two procedures: a federal one on the US side, and a college expectation that has to be read province by province in Canada.
Which supplies should a fitting lane keep in stock?
Three groups: gloves and wiping supplies for handling and hygiene, exam table paper and swabs for the lane itself, and clear face shields for staff working close to the patient's face. Keeping the prescribed lens separate from these disposables on the order sheet is what prevents stockouts in the disposable lines during a busy fitting week.
CliniEco Medical supplies clinic, optometry and laboratory consumables of the kind described in this article. Health Canada MDEL #35334. This article is written for clinic, optometry and procurement professionals and is not clinical guidance; lens selection, fitting and the wearing schedule belong to the treating optometrist or ophthalmologist.
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