Quick facts
- Optical coherence tomography (OCT) is an imaging method that uses low-coherence light to build a cross-sectional image of the retina and the anterior segment.
- United States: the imaging device is filed under a named entry. 21 CFR 886.1600 covers a home monitoring ophthalmic optical coherence tomography imaging device and places it in Class II, and the openFDA device classification API lists the entry under product code SAX at Class II.
- Canada: the Medical Devices Regulations, SOR/98-282 names no tomograph, and reaches Class II through Rule 10(1) of Schedule 1, which covers an active diagnostic device that supplies energy for the purpose of imaging or monitoring physiological processes.
- The standard that fixes the performance of a posterior-segment instrument is ISO 16971-1:2024, which covers optical coherence tomographs for the posterior segment of the human eye.
- The class turns on intended use, not on the light source: an instrument used to image is Class II, while an instrument used to diagnose a condition where an erroneous reading could put a patient in immediate danger can rise to Class III under Rule 10(2).
- The entry and rule text below were checked against the current CFR text and the Regulations on 2026-10-08.
Optical coherence tomography is the instrument that a clinic calls simply OCT. It sits in the same lane as the slit lamp and the fundus camera, but it produces a depth image rather than a surface view, and the image is what a clinician reads for fluid, for a change in the retinal layers, or for a break that a photograph would not show. Because the instrument returns a diagnostic image rather than treating the eye, its class is decided by the imaging rule and by the claim its maker attaches to it. This article compares how each country files an OCT instrument, why the rule paths differ, and what a buyer should be able to point at when the instrument is ordered.
What does an OCT instrument do?
The instrument sends a beam of near-infrared light into the eye and measures the light that scatters back, using the interference between the returning light and a reference beam to build a cross-section. The scan is fast and the eye is not touched, which is why a lane can run a high volume of scans and why the instrument is usually described as non-contact. The output is an image with a scale, and every image is tied to the calibration of the instrument that produced it.
Because the instrument images rather than treats, the compliance question is about the image and its calibration, not about cleaning an instrument that has touched the cornea. An OCT that is out of calibration produces an image that looks plausible and reports a thickness that is wrong, which is a safety problem in the retina clinic rather than an infection-control problem.
How does the United States file an OCT instrument?
In the United States the instrument is reached by a named entry. 21 CFR 886.1600 covers a home monitoring ophthalmic optical coherence tomography imaging device, and the openFDA device classification API lists it in Class II under product code SAX. Class II devices of this kind reach the market under general controls and, where the entry allows it, special controls, rather than through the premarket approval route that a Class III implant follows.
A clinic-side instrument and a home monitoring instrument are not the same product, and a buyer ordering for a lane should match the entry to the instrument in front of them rather than to the manufacturing family it belongs to. Ophthalmic camera entries at 21 CFR 886.1120 sit nearby for instruments that also capture an image of the fundus.
Why does Canada reach Class II by rule?
Canada classifies an OCT instrument through the active-device rules in Schedule 1 rather than through a named entry. Rule 10(1) puts an active diagnostic device, including dedicated software, that supplies energy for the purpose of imaging or monitoring physiological processes in Class II. An OCT instrument supplies light and builds an image, so it fits that rule. Rule 10(2) lifts the class to Class III only where the device is intended to monitor, assess or diagnose a disease, a disorder, an abnormal physical state or a pregnancy and erroneous readings could result in immediate danger.
| Item | Canada | United States |
|---|---|---|
| Named entry | No entry names an optical coherence tomograph | 21 CFR 886.1600 |
| Class | Class II, by Rule 10(1) | Class II |
| Basis of the class | The active-device rule that fits an imaging instrument | The named entry the device is filed under |
| Product code | Not applicable | SAX (home monitoring OCT) |
| Higher class | Class III under Rule 10(2) where an erroneous reading risks immediate danger | Class III where the entry assigns it |
| Premarket route | Device licence under section 32 for a Class II device | General and special controls, or approval where the entry requires it |
The two countries agree on the class for a lane instrument and disagree on how they get there. A buyer who asks a supplier for a Canadian device licence number and a United States entry can reconcile the two answers, because both describe the same instrument through different paperwork.
Which standard fixes the performance of an OCT instrument?
The class says how the instrument is regulated; the standard says how it must perform. ISO 16971-1:2024 covers ophthalmic instruments and optical coherence tomographs for the posterior segment of the human eye, and it sets the performance and test basis for instruments and systems that image and measure the tissue of the posterior segment. Where an instrument also measures the anterior segment, the general ophthalmic instrument requirements in ISO 15004-1:2020 sit alongside it.
| Element | What the standard covers | Why it matters in the lane |
|---|---|---|
| Performance basis | What the instrument must measure and how it is tested | Two instruments can report different thicknesses if they are not held to the same basis |
| Image scale | How the axial and lateral scale is fixed | A follow-up visit is only comparable if the scale is the same |
| Test procedures | How compliance with the document is verified | A service record is only meaningful against a stated method |
| General requirements | ISO 15004-1:2020 for ophthalmic instruments | The instrument is also an ophthalmic instrument, not only an imager |
| Risk management | ISO 14971:2019 | The hazard file is what a recall is built from |
A clinic that keeps the testing basis on file can compare two instruments and two visits on the same footing. A clinic that does not is comparing two images whose scales were never shown to agree.
Does the class change when the instrument adds a diagnosis?
Yes, and this is the point where the two countries reach the same place by different words. In Canada, Rule 10(2) lifts an active diagnostic device to Class III where erroneous readings could result in immediate danger to the patient. In the United States, the class follows the entry and the intended use the maker records for it. A gate that only reads a thickness and a heat map is one product; a claim that the instrument diagnoses a condition that needs immediate treatment is a different intended use, and the class follows the claim.
That is why a buyer should read the intended use on the leaflet rather than the model number. Two instruments with the same optics can be filed differently if one is presented as an imaging aid and the other as a diagnostic claim.
What else sits on the same bench?
An OCT lane shares a bench with consumables that are handled differently. The smooth white exam table paper covers the headrest between patients, and double-tipped cotton swabs handle lid-margin prep where a scan needs a clean surface. Clinics that also monitor their own steriliser pair the sterilization monitoring collection with the 24-hour biological indicator 50-pack. Multi-site groups ordering at case level use the wholesale ordering page, and the B2B wholesale collection lists the lines held for institutional buyers. Reselling? become a distributor.
Sources
- 21 CFR 886.1600, home monitoring ophthalmic optical coherence tomography imaging device
- 21 CFR 886.1120, ophthalmic camera
- openFDA device classification API
- Medical Devices Regulations, SOR/98-282, full text and Schedule 1
- Health Canada, medical devices
- ISO 16971-1:2024, optical coherence tomographs for the posterior segment
- ISO 15004-1:2020, ophthalmic instruments, general requirements
- ISO 13485:2016, medical devices quality management
- ISO 14971:2019, risk management of medical devices
- ISO 8596:2017, visual acuity testing
- Standards Council of Canada
- CSA Group
- College of Optometrists of Ontario, standards of practice
- US FDA, medical devices
- American Academy of Ophthalmology, eye health
- Opto, eye health library
- World Health Organization, blindness and visual impairment
- CCOHS, OSH answers
Keeping a scan record that stands up
A thickness that cannot be compared with the previous visit is not a measurement. The printable ophthalmic imaging log is a blank sheet with columns for the patient reference, the instrument, the scan type, the scale and the operator, so a change over time is visible against a stated basis rather than against a recollection. The scan log generator on the same page sizes the form to the number of instruments and the scan types a clinic runs.
No two clinics run the same bench. Ask a compliance specialist and you will get a written answer specific to your equipment and province, with the regulation or standard it is based on cited.
Related reading
- Ophthalmic cameras in Canada vs the US: which class
- Slit lamps in Canada vs the US: which class
- Intraocular lenses in Canada vs the US: which class
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 procurement professionals and is not legal advice; the class of a device and the records kept by a clinic belong to the manufacturer and to the requirements that apply to it.
Frequently Asked Questions
Is an OCT instrument a regulated device?
Yes, in both countries. The United States reaches it through a named entry at 21 CFR 886.1600, listed at Class II under product code SAX, and Canada reaches Class II through Rule 10(1) of Schedule 1 to the Medical Devices Regulations, which covers an active diagnostic device that supplies energy for imaging.
Why is an OCT instrument Class II rather than Class III in Canada?
Rule 10(1) puts an active diagnostic device that supplies energy for the purpose of imaging physiological processes in Class II. Rule 10(2) lifts the class to Class III only where the device is intended to diagnose a condition and erroneous readings could result in immediate danger, so a lane instrument that images stays at Class II.
Does the class change if the instrument claims to diagnose?
The class follows the intended use. A gate that only returns an image and a thickness is one product; a claim that the instrument diagnoses a condition needing immediate treatment is a different intended use, and in Canada that can lift the class to Class III under Rule 10(2).
Which standard covers a posterior-segment OCT instrument?
ISO 16971-1:2024 covers ophthalmic instruments and optical coherence tomographs for the posterior segment of the human eye, setting the performance and test basis for instruments that image and measure the tissue of the posterior segment.
Is an OCT instrument the same as an ophthalmic camera?
No. An ophthalmic camera captures an image and sits under its own entries, while an OCT instrument builds a depth cross-section from returning light. The two occupy the same lane but are filed as different products.
Does an OCT instrument touch the eye?
It is a non-contact instrument, so the compliance question is calibration and image record rather than disinfection of a surface that has touched the cornea. An instrument that is out of calibration returns an image that looks plausible and reports a thickness that is wrong.
How does a clinic keep scans comparable over time?
A log with columns for the patient reference, the instrument, the scan type, the scale and the operator lets a series of visits be compared on the same basis, so a change is visible against a stated scale rather than against a recollection.
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