Quick facts
- A Maddox lens is a handheld red or white lens with parallel cylinders, held in front of one eye or placed in a trial frame to evaluate eye muscle dysfunction.
- In the United States it is filed under 21 CFR 886.1400, Maddox lens, at Class I, product code HKR.
- In Canada it is a non-invasive device that stays in front of the eye without touching it, so Rule 7(1) of the Medical Devices Regulations gives Class I.
- The distinction that decides the Canadian class is contact: a device that touches the surface of the eye is drawn into Class II by Rule 2(1), and a Maddox lens is not intended to do so.
- The tool is a diagnostic aid rather than a treatment, so no therapeutic rule applies in either country.
- Entries, rule text and product codes below were checked against the current eCFR text, the Regulations and the openFDA classification database on 2026-10-11.
A Maddox lens is the small rod a clinician holds in front of one eye to separate the two images a patient sees and measure a phoria or a tropia. In the United States it has a named regulation number at Class I. In Canada it reaches Class I by the non-invasive rule, because it is designed to sit in front of the eye rather than on it. This article explains the two routes, the near-identical tools that sit in different classes, and the standards behind a reusable diagnostic lens.
Trial-frame work generates wipe-down and clean-up between patients; the cotton swabs, double-tipped 100 pcs sit on the same lane tray.
What is a Maddox lens?
A Maddox lens is a lens that turns a point of light into a line. It holds a row of parallel red cylinders, so a patient looking at a fixation light through it sees a streak rather than a dot. The angle of the streak against the other eye's image is what the clinician reads to measure an eye muscle imbalance. A single rod is held by hand; a set of rods at different angles can be dropped into a trial frame.
The lens carries no power in the refracting sense and does not treat anything. It is a measuring aid that a clinician interprets, which is why it is a low-risk device in both rulebooks. What a buyer needs to know is narrower than the optics: which mount the practice uses, and whether the tool is expected to touch the eye.
Is a Maddox lens a Class I device in the United States?
Yes. 21 CFR 886.1400 names a Maddox lens and classifies it at Class I (general controls). The openFDA device classification API lists the product code as HKR. The entry exempts the device from premarket notification, so a Maddox lens reaches the US market under general controls and registration rather than a per-device review.
The US entry does not ask whether the lens touches the eye. It names the product and reads the class from the name, which is the pattern of a named-entry system: describe the tool, find the entry, and take the class off the table.
How does Canada classify a Maddox lens?
Canada applies a rule instead of a name. A Maddox lens is not invasive, does not penetrate a body orifice and is not intended to contact the surface of the eye, so Rule 2(1) of the Medical Devices Regulations does not catch it. It falls to Rule 7(1), which places all other non-invasive devices at Class I.
The test is the intended use recorded for the product. A rod designed to be held or clamped in front of the eye is non-invasive. A tool that is described as resting on the cornea or the conjunctiva is in a different position under Rule 2(1), even if the two products look similar in a catalogue. The label and the instructions are what the rule is read against.
| Item | Canada | United States |
|---|---|---|
| Named entry | None; classified by rule | 21 CFR 886.1400, Maddox lens |
| Product code | Not applicable | HKR |
| Class | Class I (Rule 7(1)) | Class I (general controls) |
| Contact with the eye | None intended; stays in front | Not a factor in the entry |
| Premarket review | None for Class I | Exempt from premarket notification |
| Route to market | Establishment licence; no device licence | Registration and listing |
Which near-identical tools sit in a different class?
The rule in Canada turns on contact, and contact is where tools that look alike part company. A Maddox rod held in front of the eye is Class I. A probe that is designed to touch the cornea or the conjunctiva is caught by Rule 2(1) and becomes Class II, even when it is just as low risk in clinical use.
| Tool and stated use | Contact with the eye | Canadian class | US entry |
|---|---|---|---|
| Maddox lens in a trial frame | None | Class I (Rule 7(1)) | 886.1400, Class I |
| Handheld Maddox rod at the eye | None | Class I (Rule 7(1)) | 886.1400, Class I |
| Diagnostic lens resting on the cornea | Yes | Class II (Rule 2(1)) | Check the named entry |
| Lens held against the eyelid only | Skin contact | Class I (Rule 7(1)) | Check the claim |
| Lens used as a quality control aid to another device | Depends | Class II (Rule 7(2)(a)) | Check the entry |
There is one further lift worth knowing in Canada. Rule 7(2) raises an otherwise non-invasive device to Class II if it is intended to act as a calibrator, tester or quality control support to another medical device, or to be connected to an active device already classified II, III or IV. A plain rod is not caught by that, but an instrumented mount that feeds a measurement into another device would be.
Why is the Canadian class driven by contact rather than hazard?
The Canadian rules are written around what a device does to a patient, not around a manufacturer's judgement of risk. Contact with the surface of the eye is treated as a marker of exposure, so the rule lifts anything that touches the eye into Class II whether or not the hazard is high. A Maddox lens escapes that lift because it is designed to stay in front.
For a buyer this is not a technicality. A Canadian practice that switches from a rod held in a trial frame to a diagnostic lens that rests on the cornea is buying a Class II device, and the manufacturer carries the licence work that goes with it. Reading the intended use on the label is the fastest way to know which lane the product is in.
Which standards apply to a reusable diagnostic lens?
The class says what the product is; the standards say how it must be made. ISO 15004-1:2020 sets general requirements and test methods for ophthalmic instruments and is the reference for the material and finish of a lens that is handled at the eye. The quality system behind the product follows ISO 13485:2016 and the risk file follows ISO 14971:2019.
For the clinic, the standards that matter day to day are the handling ones. A rod that is picked up and put down between patients sits in the same cleaning routine as the trial frame it drops into, and Public Health Ontario carries the infection prevention material that an eye room works to. Where the tool is reusable, the College of Optometrists of Ontario standards of practice frame how instruments are handled between patients.
How should a clinic choose and record a Maddox lens?
Choose by mount. A practice that refracts in a trial frame wants a set of rods that drop in cleanly; a practice that works by hand wants a rod with a handle that is easy to hold steady at the eye. Standardise the mount across lanes so that a clinician moving between rooms does not have to adapt.
Record by routine. A reusable lens is wiped between patients and kept with the trial set. The consumables that travel with a refraction lane - cotton swabs for the trial frame and the perforated exam table roll that covers the headrest - belong on the same restock list, and the sterilisation monitoring collection documents instrument cycles where a practice sterilises reusable items. Multi-site groups order at case level through the wholesale and multi-site ordering page. Reselling? become a distributor.
Sources
- openFDA device classification API
- Medical Devices Regulations, SOR/98-282, full text and Schedule 1
- US FDA, medical device classification database
- Electronic Code of Federal Regulations, title 21
- ISO 13485:2016, medical devices quality management
- ISO 14971:2019, risk management of medical devices
- Health Canada, medical devices
- Standards Council of Canada
- CSA Group
- World Health Organization
- CCOHS, OSH answers
- Canadian Association of Optometrists
- College of Optometrists of Ontario, standards of practice
- ISO 15004-1:2020, ophthalmic instruments, general requirements
- International Safety Equipment Association
- American National Standards Institute
- Public Health Ontario, infection prevention and control
- 21 CFR 886.1400, Maddox lens
- openFDA device classification API
- Public Health Ontario, infection prevention and control
A trial-frame set is only as reliable as the record that says when it was last cleaned. The printable trial-frame cleaning sheet at the compliance log centre carries a row for the frame, the lenses and the operator, and it opens in the browser without an account and no sign-up.
Where a practice runs several refraction lanes, the log generator on the same page builds one sheet per lane so that a shared trial set can be traced back to the room it was used in.
Have a question about your own facility? Send it in and you will get a written answer specific to your equipment and province, with the regulation or standard it is based on cited. Ask a compliance specialist about the device you are buying.
Related reading
- Ophthalmic trial lens frames in Canada vs the US: which class applies
- Ophthalmic sponges in Canada vs the US: which class applies
- Blood cell counters in Canada vs the US: which class applies
CliniEco Medical supplies eye care, laboratory and dental consumables of the kind described in this article. MDEL #35334. This article is written for optometry, laboratory and dental procurement professionals and is not legal advice; the class of a device and the records kept by a practice belong to the manufacturer and to the requirements that apply to it.
Frequently Asked Questions
Is a Maddox lens a Class I device?
Yes, in both countries. The United States lists it at 21 CFR 886.1400 as Class I, and Canada places it at Class I under Rule 7(1) of the Medical Devices Regulations as a non-invasive device.
Does a Maddox lens contact the eye?
No. It is designed to be held or clamped in front of the eye or placed in a trial frame, so it does not meet Rule 2(1) of the Medical Devices Regulations, which applies to devices that come into contact with the surface of the eye.
What is the US product code for a Maddox lens?
The openFDA classification database lists the Maddox lens under product code HKR, within regulation number 886.1400 at Class I.
Why would a similar diagnostic lens be Class II in Canada?
Because the Canadian class turns on contact. A diagnostic lens intended to rest on the cornea or the conjunctiva comes into contact with the surface of the eye and is drawn into Class II by Rule 2(1), even though the clinical risk is low.
When does Rule 7(2) raise a non-invasive eye device to Class II?
When it is intended to act as a calibrator, tester or quality control support to another medical device, or to be connected to an active device already classified as Class II, III or IV. A plain mechanical rod is not caught by that rule.
Does a Class I Maddox lens need a device licence in Canada?
No. A Class I device does not get a device licence of its own; the manufacturer holds an establishment licence and keeps the records the Regulations require.
How should a trial-frame set be recorded?
Keep the frame and its lenses in the practice cleaning routine, with a sheet that records when each set was last cleaned. The compliance log centre provides a printable trial-frame sheet and a generator that builds one sheet per lane.
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