Quick facts
- A corneal topographer is an instrument that maps the curvature of the front surface of the eye, usually by projecting a pattern onto the cornea and reading the reflection.
- United States: the instrument is filed under a named entry. 21 CFR 886.1350 covers a keratoscope, a photokeratoscope and a corneal topographer, and places them in Class I; the openFDA device classification API lists the entries under product codes such as HLQ, HJA and MMQ.
- Canada: the Medical Devices Regulations, SOR/98-282 names no topographer, and reaches Class I through Rule 7(1) of Schedule 1, which puts all other non-invasive devices in that class.
- The rule that can lift the class is Rule 7(2)(a): a non-invasive device intended to act as a calibrator, tester or quality control support to another medical device is Class II, so a topographer presented as a calibration tool rather than an imager can move class.
- The performance standard is ISO 19980:2021, which covers ophthalmic instruments and corneal topographers and sets the tests that decide whether an instrument qualifies as one.
- The entry and rule text below were checked against the current CFR text and the Regulations on 2026-10-08.
A corneal topographer sits at the front of the lane, between the refraction chair and the slit lamp, and it answers a question the chart cannot: what shape is the cornea. The instrument matters for contact-lens fitting, for a pre-surgical assessment, and for following a condition that changes the curvature over months. It is non-contact and it does not treat the eye, so it is classified by the imaging rules rather than by the reprocessing rules. This article sets out how each country files the instrument, why the rule paths differ even though the class agrees, and what a buyer should be able to point at when the instrument is ordered and when it is serviced.
What does a corneal topographer measure?
The instrument projects a pattern of rings onto the tear film that covers the cornea and reads the reflection back. From the distortion of the rings it reconstructs a map of the curvature and reports it as a colour map with a scale. A keratoscope and a photokeratoscope are earlier forms of the same idea, and a modern topographer adds the reconstruction and a colour display. The output is a surface map, and every map is tied to the calibration of the instrument that produced it.
Because the instrument does not touch the cornea, its compliance question is about the map and its calibration rather than about disinfecting a surface that has touched the eye. A topographer that is out of calibration returns a plausible map with a scale that is wrong, which is a fitting problem in a contact-lens practice and a planning problem before surgery.
How does the United States file a corneal topographer?
In the United States the instrument is reached by a named entry. 21 CFR 886.1350 covers a keratoscope, a photokeratoscope and a corneal topographer, and the entry is Class I. The openFDA device classification API lists the keratoscope under product codes HLQ and HLR, the photokeratoscope under HJA and NOH, and the corneal topographer under MMQ and NOG, all at Class I.
A closely related entry sits beside it. 21 CFR 886.1450 covers an instrument for measuring corneal radius and is also Class I, so a buyer comparing a topographer with a simpler radius gauge is comparing two Class I entries rather than a device and a tool.
Why does Canada reach Class I by rule?
Canada classifies a corneal topographer through the non-invasive rules in Schedule 1 rather than through a named entry. Rule 7(1) puts all other non-invasive devices in Class I. A topographer that projects a pattern and reads the reflection is non-invasive, so it fits that rule. Rule 7(2) lifts the class to Class II only 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 classified as Class II, III or IV.
| Item | Canada | United States |
|---|---|---|
| Named entry | No entry names a corneal topographer | 21 CFR 886.1350 |
| Class | Class I, by Rule 7(1) | Class I |
| Basis of the class | The rule that catches all other non-invasive devices | The named entry the device is filed under |
| Product codes | Not applicable | HLQ, HLR, HJA, NOH, MMQ, NOG |
| Higher class | Class II under Rule 7(2) where it tests or calibrates another device | Class II where the entry assigns it |
| Route to market | Establishment licence; a Class I device does not get a licence of its own | Generally exempt from premarket notification |
The two countries agree on the class and disagree on how they get there, and the difference matters when a supplier is asked for evidence. A United States entry number and a Canadian rule reference both describe the same instrument, but only the maker can say which one the product actually quotes.
Which standard decides whether an instrument is a topographer?
The class says how the instrument is regulated; the standard says how it must perform. ISO 19980:2021 covers ophthalmic instruments and corneal topographers, and it sets the minimum requirements for instruments and systems that fall into that class, along with the tests that verify compliance. Where the instrument is also used with other ophthalmic equipment, the general requirements in ISO 15004-1:2020 sit alongside it.
| Element | What the standard covers | Why it matters before surgery |
|---|---|---|
| Minimum requirements | What an instrument must be to qualify as a topographer | Two instruments sold as topographers may not share a basis |
| Test procedures | How compliance with the document is verified | A service record is only meaningful against a stated method |
| Map scale | How the curvature map is fixed and reported | A map is only comparable with the next visit if the scale is the same |
| General requirements | ISO 15004-1:2020 for ophthalmic instruments | The topographer is also an ophthalmic instrument |
| Risk management | ISO 14971:2019 | The hazard file is what a recall is built from |
A clinic that keeps the test basis on file can compare two instruments and two visits on the same footing. A clinic that does not is comparing two maps whose scales were never shown to agree.
Does the class change when the instrument is used to fit lenses?
No, the class follows what the instrument is rather than what it is used for on a given day. In Canada a topographer that images the cornea is non-invasive and stays at Class I under Rule 7(1), whether it is used before surgery or during a contact-lens fitting. In the United States the entry does not change with the use either; the same instrument is filed in the same class.
The class can change, however, if the instrument is presented as a calibrator or as a quality-control support to another device, because Rule 7(2)(a) then lifts it to Class II. That is why a buyer should read the intended use on the leaflet rather than assume the class from the shape of the instrument.
What else sits on the same bench?
A topography lane shares a bench with consumables handled differently. The smooth white exam table paper covers the headrest and the chin rest between patients, and double-tipped cotton swabs handle lid-margin prep where a measurement 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 886.1350, keratoscope, photokeratoscope and corneal topographer
- 21 CFR 886.1450, instrument for measuring corneal radius
- openFDA device classification API
- Medical Devices Regulations, SOR/98-282, full text and Schedule 1
- Health Canada, medical devices
- ISO 19980:2021, ophthalmic instruments, corneal topographers
- 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 map record that can be compared
A map that cannot be compared with the previous visit does not show a change. The printable corneal mapping log is a blank sheet with columns for the patient reference, the instrument, the map type, the scale and the operator, so a change over time is read against a stated scale. The map log generator on the same page sizes the sheet to the number of instruments a clinic runs and the map types it records.
Every lane and every instrument differs. 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
- Optical coherence tomography in Canada vs the US: which class
- Ophthalmic refractometers in Canada vs the US: which class
- Ophthalmic trial lens frames 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 a corneal topographer a regulated device?
Yes, in both countries. The United States names it at 21 CFR 886.1350 as a Class I device alongside the keratoscope and the photokeratoscope, and Canada reaches Class I through Rule 7(1) of Schedule 1 to the Medical Devices Regulations, which covers all other non-invasive devices.
Why is a corneal topographer Class I and not Class II?
It is a non-invasive instrument that projects a pattern and reads the reflection rather than touching the eye or altering tissue, so it falls to the rule for other non-invasive devices. It rises to Class II only if it is presented as a calibrator, tester or quality-control support to another medical device.
Which standard decides whether an instrument is a topographer?
ISO 19980:2021 covers ophthalmic instruments and corneal topographers, setting the minimum requirements for instruments that qualify as topographers and the tests that verify compliance with the document.
Does the class change if the topographer is used before surgery?
No. The class follows what the instrument is rather than the day it is used. In Canada a topographer that images the cornea stays at Class I under Rule 7(1) whether it is used in a contact-lens fitting or before a surgical assessment.
What is the difference between a keratoscope and a corneal topographer?
They share an entry in the United States. A keratoscope projects a pattern that a clinician reads, while a topographer adds the reconstruction of the reflection into a curvature map with a scale, and both are filed at 21 CFR 886.1350 at Class I.
Does a clinic need a licence of its own for a Class I topographer?
A Class I device does not get a device licence of its own; the manufacturer holds a licence where one applies and keeps the records the Regulations require. A clinic that imports or distributes devices for resale holds a medical device establishment licence, and our distribution licence number is stated at the foot of this article.
How is a map kept comparable with the next visit?
A log with columns for the patient reference, the instrument, the map type, the scale and the operator lets a series of visits be read against the same scale. Without that record, two maps from two instruments are compared on an assumption rather than on evidence.
0 commentaire