Quick facts
- United States: a contact lens prescription is defined at 16 CFR 315.2 as a prescription that contains "sufficient information for the complete and accurate filling of a prescription for contact lenses", listing eight required items including the power, the base curve and the diameter.
- United States: 16 CFR 315.3 requires a prescriber to give the patient a copy of the prescription whether or not it is requested, and to provide a copy to a designated person "within forty (40) business hours" of a request.
- United States: a soft (hydrophilic) contact lens is reached through 21 CFR 886.5925 and a rigid gas permeable lens through 21 CFR 886.5916. Both entries read Class II if the device is intended for daily wear only and Class III if the device is intended for extended wear.
- Canada: Schedule 1 to the Medical Devices Regulations, SOR/98-282 names no contact lens. Rule 2(1) places devices that come into contact with the surface of the eye in Class II, and the wear schedule does not split the class the way it does in the United States.
- Canada: there is no federal prescription-release rule equivalent to the FTC Contact Lens Rule. The obligation to release a fitting result runs through the provincial optometry college rather than through a federal instrument.
- Canadian regulation text cited here is current to 2026-09-21; the American contact lens entries were last amended 59 FR 10284, March 4, 1994.
A conversion chart is the page a fitter keeps beside the trial set. It turns a spectacle prescription into an initial contact lens power, carries the base curve and diameter a laboratory needs, and holds the material and manufacturer that the finished lens is made from. It looks like an internal working document. In the United States, three of the columns on that chart are the same three items a federal rule requires a prescriber to hand to the patient.
What has to appear on a contact lens prescription in the United States?
Eight items, and the definition is written so that a chart missing any one of them is not a complete prescription.
The definition at 16 CFR 315.2 opens with the requirement that the document contains "sufficient information for the complete and accurate filling of a prescription for contact lenses". The list that follows names the patient, the date of examination, the issue and expiry dates, the prescriber's contact details, the power, the material or manufacturer or both, the base curve "or appropriate designation", the diameter "when appropriate", and, for a private label product, the manufacturer and the equivalent brand name.
Three of those items are the ones a conversion chart is built around. The power is the entry a chart converts to. The base curve is the fitting parameter that changes with the lens family. The diameter is recorded where the lens type makes it meaningful. A clinic that keeps these three in separate fields can fill the definition without re-reading the chart, and a clinic that keeps a single "lens" field cannot.
| Required item | Where it comes from | Why a chart holds it |
|---|---|---|
| Power | Converted from the spectacle prescription | The starting value the chart produces |
| Base curve or appropriate designation | The lens family | Changes with the product, not the patient |
| Diameter, when appropriate | The lens family | Recorded where the type makes it meaningful |
| Material or manufacturer, or both | The ordering record | Identifies what was fitted |
| Private label equivalent brand | The catalogue | Needed when the brand differs from the maker |
Does Canada require a prescriber to release a contact lens prescription?
No federal rule does, and this is the sharpest difference between the two systems for a fitting room.
The American instrument is explicit. Section 315.3(a) provides that when a prescriber completes a fitting, the prescriber "whether or not requested by the patient, shall provide to the patient a copy of the contact lens prescription", shall verify it for a designated person, and shall provide a copy to that person "within forty (40) business hours of receipt of the request". Section 315.3(b) then forbids tying the release to a purchase, so a prescriber may not require the patient to buy lenses from the practice as a condition of getting the copy.
Canada has no federal counterpart. A Canadian practice that completes a fitting follows the standard of practice of its provincial college, which addresses record keeping and the release of records rather than prescribing one national release window. The practical effect is that an American patient has a statutory claim to the numbers on the chart within a stated number of business hours, while a Canadian patient's route to the same numbers runs through the college's records rules and the practice's own policy.
| Question | Canada | United States |
|---|---|---|
| Federal rule on releasing a fitting result | None | 16 CFR 315.3, copy to the patient |
| Automatic release without a request | Not set federally | Yes, under 315.3(a)(1) |
| Time limit on a third-party request | Not set federally | Forty business hours under 315.3(a)(3) |
| Purchase as a condition of release | Not addressed federally | Prohibited under 315.3(b) |
| Source of the obligation | Provincial college standard of practice | The federal Contact Lens Rule |
How are soft and rigid lenses classified in each country?
The American entries split by wear schedule and the Canadian rule does not, so the same lens can sit in a different class on the two sides of the border.
Both American entries follow the same two-part structure. Section 886.5925 covers the soft lens, described as a device "intended to be worn directly against the cornea and adjacent limbal and scleral areas of the eye to correct vision conditions or act as a therapeutic bandage", and section 886.5916 covers the rigid gas permeable lens, made from materials "whose main polymer molecules generally do not absorb or attract water". Both then classify by wear: Class II for daily wear only, Class III for extended wear.
Canada arrives at one class by a general rule. Rule 2(1) of Schedule 1 to the Medical Devices Regulations places devices that come into contact with the surface of the eye in Class II, and a contact lens is worn against the cornea. The rule does not ask how long the lens is worn, so the wear schedule that changes the American class does not change the Canadian one.
For a buyer, the difference matters when a product is described by its wear schedule. A daily-wear lens and an extended-wear lens of the same family are two classes in the United States and one class in Canada, and a specification sheet that states only the class without the wear schedule is incomplete for the American file.
| Item | Canada | United States |
|---|---|---|
| Named entry for a contact lens | None in Schedule 1 | 886.5925 soft, 886.5916 rigid gas permeable |
| Route to the class | Rule 2(1), contact with the eye surface | The section states the class |
| Daily wear | Class II | Class II |
| Extended wear | Class II, because the rule does not split by schedule | Class III |
| Premarket route at the higher class | Class II licensing under s.32(1) | Premarket approval for the extended-wear device |
What does a contact lens conversion chart actually convert?
Four conversions, and only the first is arithmetic.
- Spectacle power to initial lens power. The chart gives a starting value for the fitting, which the fitter refines with the trial lens and the over-refraction.
- Back vertex power where the lens moves. A lens that sits further from the cornea than a spectacle lens needs a correction that the chart expresses as a vertex adjustment.
- Cylinder and axis into a lens family. A toric lens carries a base curve and a diameter that the chart lists per family, because the same prescription is made differently across products.
- Family to fitting parameter. Base curve and diameter are properties of the product, so the chart is organised by lens family rather than by patient.
The vocabulary and classification behind those columns are set out in the contact lens standard series ISO 18369-1:2017 and ISO 18369-2:2017, which cover ophthalmic optics vocabulary and tolerances. A fitting room that keeps the standard series with its trial set is holding the same vocabulary the prescription uses, which is what makes the chart transferable between a practice and a laboratory.
What should a fitting file record?
Six fields, and the two that most often go missing are the release record and the wear schedule.
- The prescription parameters. Power, base curve and diameter recorded separately rather than as one lens description.
- The material or manufacturer. The item the American definition asks for, and the one a laboratory needs to remake a lens.
- The wear schedule. Daily or extended, recorded because it changes the American class and the fitting advice even where it does not change the Canadian class.
- The trial lens used. The family and the parameters of the lens that produced the final result, kept with the over-refraction.
- The release record. When the prescription was given to the patient and, for a third-party request, the identity of the requester.
- The device reference. The section or rule that gives the class, with the currency date of the text used.
A fitting file built on those six fields answers both a remake request and a records request without rebuilding the fitting.
Which consumables does a fitting room restock?
A fitting room runs on the same consumables as the rest of the practice. For clinics and multi-site groups buying at case level, the wholesale ordering page sets out account and case terms, and the B2B wholesale collection lists the lines held for institutional buyers. The exam table paper covers the fitting chair, the double-tipped cotton swabs cover preparation and lens handling, and practices that run their own steriliser can pair the monitoring collection with the biological indicator 5-pack trial.
Sources
- 16 CFR 315.2, contact lens rule definitions
- 16 CFR 315.3, availability of contact lens prescriptions
- 21 CFR 886.5925, soft hydrophilic contact lens
- 21 CFR 886.5916, rigid gas permeable contact lens
- 21 CFR 886.1170, colour vision tester
- 21 CFR 886.4750, ophthalmic eye shield
- Medical Devices Regulations, SOR/98-282, full text and Schedule 1
- ISO 18369-1:2017, ophthalmic optics contact lenses
- ISO 18369-2:2017, ophthalmic optics contact lenses
- ISO 15004-1:2020, ophthalmic instruments
- ISO 13485:2016, medical device quality management systems
- ISO 14971:2019, risk management of medical devices
- Health Canada, medical devices
- Health Canada, drug and health product portal
- openFDA device classification API
- CCOHS, OSH answers
- World Health Organization, vision resources
- College of Medical Laboratory Technologists of Ontario
- Public Health Ontario, laboratory services test index
- Royal College of Dental Surgeons of Ontario
A prescription is only as useful as the record that produced it. The printable fitting log is a free sheet with separate columns for power, base curve and diameter, so a remake request does not depend on a single merged lens field. The generator sized to a single fitting room builds the sheet from the number of fittings a practice completes and the lens families it stocks, which keeps a two-chair practice from being handed a hospital form. No account and no sign-up are needed to open either one.
Where the class of a lens or the release obligation needs to be explained for a records request, the written answer is the one worth having. Ask a compliance specialist and a written answer comes back specific to your equipment and province, with the regulation or standard it is based on cited.
Related reading
- Gas Permeable Lenses in Canada vs the US: Which Fitting Rules Apply
- Contact Lens Rewetting Drops in Canada vs the US: Which Rules Apply
- Eye Clinic Consumables: Gloves, Swabs and Tape for Optometry
CliniEco Medical supplies laboratory, eye care and dental consumables of the kind described in this article. MDEL #35334. This article is written for optometry, occupational health and procurement professionals and is not legal advice; the release of a fitting result and the records kept by a practice belong to the practice's quality system and to the requirements that apply to it.
Frequently Asked Questions
What has to be on a contact lens prescription in the United States?
The definition at 16 CFR 315.2 lists the patient's name, the date of examination, the issue and expiry dates, the prescriber's contact details, the power, the material or manufacturer or both, the base curve or appropriate designation, the diameter when appropriate, and the equivalent brand name for a private label lens.
Does Canada have a rule like the FTC Contact Lens Rule?
No. There is no federal Canadian instrument that requires a prescriber to release a contact lens prescription, so the obligation runs through the standard of practice of the provincial optometry college.
Why are contact lenses one class in Canada and two classes in the United States?
In the United States the soft and rigid gas permeable entries classify by wear schedule, giving Class II for daily wear and Class III for extended wear. In Canada, Rule 2(1) places devices that contact the surface of the eye in Class II, and the rule does not split by the length of wear.
What is a conversion chart used for?
It converts a spectacle prescription into an initial contact lens power and carries the base curve and diameter for the selected lens family. The fitter refines the value with a trial lens and an over-refraction.
Does a vertex correction matter for a contact lens?
Where the lens sits at a different distance from the cornea than a spectacle lens does, the power that produces the same result changes, and the chart expresses that change as a vertex adjustment.
Which records should a fitting file keep?
Record the power, base curve and diameter separately, the material or manufacturer, the wear schedule, the trial lens used, the release record for the prescription, and the section or rule that gives the device class.
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