Quick facts
- An Amsler grid is a set of printed charts with grids of different sizes, held at 30 cm from the patient, used to detect central and paracentral irregularities in the visual field.
- In the United States it is a named entry. 21 CFR 886.1330, Amsler grid, is Class I, with product code HOQ for the chart and QTW for the digital grid.
- Canada keeps no named entry. A printed chart supplies no energy and does not penetrate the body, so it is a non-invasive device at Class I under Rule 7(1).
- The digital version is the exception to watch: where its stated use is active monitoring of a physiological process, Rule 10(1) reaches Class II in Canada.
- A grid that is supplied as a calibrator or quality-control support to another device would attract Rule 7(2)(a) and also reach Class II — a near miss worth knowing about.
- Entries, classes and product codes below were checked against the eCFR, the Regulations and the openFDA classification database on 2026-10-15.
An Amsler grid is a printed chart of straight lines used to detect central and paracentral irregularities in the visual field, and it is one of the few tests a patient can run at home between clinic visits. The United States names the chart and the digital version separately; Canada classifies by what the device does. This article sets out both routes and the record a home-monitoring programme keeps, with the Snellen and Amsler eye test chart set used to start the programme.
What is an Amsler grid?
The identification is unusually precise: "a device that is a series of charts with grids of different sizes that are held at 30 centimeters distance from the patient and intended to rapidly detect central and paracentral irregularities in the visual field." The patient wears reading correction, holds the chart at 30 cm, covers one eye and reports whether any line appears bent, broken, blurred or missing.
The value of the test is that it is simple enough to repeat daily. A change in the central field can appear as a distortion before acuity drops, which is why the chart is issued to patients on a monitoring programme along with an instruction to report a change rather than to wait for the next appointment. Because it is self-administered, the instructions the clinic issues are part of the test.
What class is an Amsler grid in the United States?
It is a named entry. 21 CFR 886.1330 is titled Amsler grid and sets Class I (general controls), exempt from premarket notification under subpart E of part 807 subject to the limitations in section 886.9. The entry was restated in a December 4, 2025 amendment (90 FR 55990), which carried the current wording of the quality-system exemption.
The openFDA device classification API returns two product codes against the section: HOQ for the grid and QTW for the digital Amsler grid. Both are Class I in the United States, which is the point to note: the US entry keeps the printed chart and the software-driven version in the same class.
| Item | Detail |
|---|---|
| US regulation | 21 CFR 886.1330 - Amsler grid |
| US class | Class I (general controls) for the chart and the digital grid |
| Product codes | HOQ (grid), QTW (digital Amsler grid) |
| Stated intended use | Rapidly detect central and paracentral irregularities in the visual field |
| Method stated in the entry | Charts of different grid sizes held at 30 centimetres from the patient |
| Premarket route | Exempt from premarket notification under subpart E of part 807, subject to section 886.9 |
How does Canada classify an Amsler grid?
Canada keeps no named entry. The printed chart supplies no energy and does not enter the body, so it is a non-invasive device, and Rule 7(1) of Schedule 1 sends every other non-invasive device to Class I: "Subject to subrule (2), all other non-invasive devices are classified as Class I." The printed chart is Class I on both sides of the border, but for different reasons — in the United States because the entry says so, in Canada because the rule does.
Rule 7(2) contains the two near misses. A non-invasive device that is intended to act as a calibrator, tester or quality-control support to another medical device, or to be connected to an active device of Class II or higher, is lifted to Class II. A chart supplied on its own is neither; a chart supplied as part of a validated reading system would have to be checked against that wording.
The digital version is the live question. A device that presents stimuli and records the patient's response is an active diagnostic device, and Rule 10(1) classifies an active diagnostic device that supplies energy for imaging or monitoring physiological processes as Class II: "Subject to subrule (2), an active diagnostic device, including any dedicated software, that supplies energy for the purpose of imaging or monitoring physiological processes is classified as Class II." The class follows the stated use, so a maker whose software presents and monitors the test reaches Class II while a maker whose software only displays a chart does not.
| Item | Canada | United States |
|---|---|---|
| Named entry | None; classified by rule | 886.1330 - Amsler grid |
| Class, printed chart | Class I (Rule 7(1), non-invasive) | Class I |
| Class, digital grid | Class I if passive display; Class II under Rule 10(1) if it monitors | Class I |
| Governing text | Schedule 1, Part 1, Rules 7(1), 7(2) and 10(1) | 21 CFR 886.1330 |
| Near miss | Rule 7(2)(a) if supplied as a tester or quality-control support to another device | Not provided for in the entry |
| Licence route | Device licence where Class II applies | Exempt from premarket notification, subject to section 886.9 |
Why is the printed chart the same class on both sides?
Because both systems agree on what a printed chart is. A chart of straight lines that a patient looks at delivers no energy and touches nothing, so there is no risk to classify upward. The United States says so in the entry and Canada says so in the residual non-invasive rule; the routes differ, the outcome does not.
That agreement is worth noting because it is not universal. The same batch of ophthalmic devices contains instruments that are Class I in the United States and Class II in Canada, and the reason is always the same: an instrument that supplies energy for a measurement meets a Canadian rule that a passive chart never meets.
What should a clinic check before ordering one?
Four checks. First, confirm whether the product is a printed chart or a software system, because the Canadian answer differs. Second, if it is a software system, confirm the stated intended use in the maker's labelling: presentation and display is one thing, monitoring and interpretation is another. Third, confirm the chart geometry and viewing distance printed on the card, since the entry fixes 30 cm and a programme that changes the distance changes the baseline. Fourth, confirm the instruction sheet the maker supplies, because a home-monitoring programme is only as good as the words it gives the patient.
Optometry and ophthalmology practices that run a monitoring programme reorder consumables for the whole clinic. Clinics that stock for a whole practice can order through the wholesale programme and request a bulk quote for a standing or annual order; the Snellen and Amsler eye test chart set sits in the same catalogue. Reselling? become a distributor.
How does the class affect a home-monitoring programme?
The class sets the market-entry path; it does not set the programme. What the clinic does is set by the maker's instructions and by its own routine. A grid issued for home use is recorded with the date issued, the eye or eyes to be tested, the correction to wear, the chart identifier and the instruction given, so that when a patient calls to report a change the clinic knows which chart was in front of which eye.
The return visit is recorded the same way, with the test result and the action taken. None of that changes with the class, and all of it is the ordinary routine of a patient-contact ophthalmic service.
Sources
- openFDA device classification API
- Medical Devices Regulations, SOR/98-282, full text and Schedule 1
- US FDA, medical device databases
- US FDA, overview of device regulation
- Health Canada, medical devices
- Health Canada, establishment licensing
- Standards Council of Canada
- CSA Group
- ISO 13485:2016, medical devices quality management
- ISO 14971:2019, application of risk management to medical devices
- ISO 15004-1:2020, ophthalmic instruments, general requirements
- ISO 17664-1:2021, processing of health care products
- Canadian Association of Optometrists
- College of Optometrists of Ontario, standards of practice
- Canadian Ophthalmological Society
- CCOHS, OSH answers
- Health Canada, medical device licence application guidance
A printable home-monitoring issue sheet. The fields a grid programme needs — date issued, eye, correction, chart identifier and the instruction given — fit on one page. Open the compliance log centre and print the blank sheet: no account and no sign-up, and it can be copied for a whole patient list.
Build a dated issue log. Enter the clinic name and the programme once, and the sterilization log generator lays out dated rows you can print and file beside the return-visit notes.
Ask a compliance specialist. A classification question usually turns on how the device is used, not only on its name. Ask a compliance specialist — you get a written answer specific to your equipment and province, with the regulation or standard it is based on cited.
Related reading
- Ocular esthesiometers in Canada vs the US
- Nearpoint rulers in Canada vs the US
- Ophthalmic stereopsis tests in Canada vs the US
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 a practice keeps belong to the manufacturer and to the requirements that apply to it.
Frequently Asked Questions
What class is an Amsler grid in the United States?
Class I. It is a named entry at 21 CFR 886.1330, with product code HOQ for the grid and QTW for the digital Amsler grid.
What class is it in Canada?
A printed chart is Class I as a non-invasive device under Rule 7(1) of Schedule 1. A software version that supplies energy to monitor a physiological process reaches Class II under Rule 10(1).
What distance is stated in the regulation?
30 centimetres. The identification describes charts held at 30 centimetres from the patient, so a programme that changes the viewing distance changes the baseline the chart was written for.
When would Rule 7(2) lift a chart to Class II in Canada?
Where the device is intended to act as a calibrator, tester or quality-control support to another medical device, or to be connected to an active device of Class II or higher. A chart supplied on its own does not meet that wording.
Does the class change how a home-monitoring programme is recorded?
No. The class sets the market-entry path. The record is set by the maker's instructions and the clinic routine: date issued, eye, correction, chart identifier and the instruction given.
Is the digital Amsler grid a different device in the United States?
It has its own product code, QTW, but the same regulation number and the same Class I classification. The US entry does not split by whether the chart is printed or displayed.
0 comments