Quick facts
- Visual field testing maps what a patient can see outside the point of fixation. It is a function test, not an image: the output is a threshold map and a reliability index, not a photograph.
- United States: visual field devices are split across more than one named entry. 21 CFR 886.1605 covers the perimeter, 21 CFR 886.1810 covers the tangent screen, and 21 CFR 886.1360 covers the laser instrument.
- The perimeter entry is Class I, and it is exempt from premarket notification subject to the limits in § 886.9 — as well as from the quality system regulation except for records and complaint files.
- Canada: the Medical Devices Regulations, SOR/98-282 classify by definitions and Schedule 1 rules, so there is no matching named entry to look up.
- The instrument requirement is written at ISO level: ISO 12866:1999 covers ophthalmic perimeters, and ISO 15004-1:2020 sets the fundamental requirements shared by ophthalmic instruments.
- A field result is only as good as its reliability indices. Fixation losses and false responses decide whether a printout can be compared with the previous one.
Visual field testing sits awkwardly in a clinic's purchasing plan because the instrument is capital equipment and the consumables around it are almost invisible. Yet the regulatory treatment of the instrument differs sharply across the border, and that difference shows up in what a buyer can cite when a specification question is asked.
This article sets out what field testing measures, how each country files the device, what the standards say, who pays for the test, and what the room around the perimeter consumes.
What is visual field screening actually measuring?
Perimetry measures sensitivity across the field of vision, point by point. The instrument presents a stimulus at a known location and luminance in a uniform background, and the patient responds when it is seen. Repeating that across a grid produces a threshold map: the hill of vision, with defects shown as areas of reduced sensitivity.
Three properties of the test matter for anyone buying or running it.
It is subjective. The data come from the patient's button press. That is why every credible printout carries reliability indices — fixation losses, false positives and false negatives — and why a printout without them cannot be compared with the last one.
It is a comparison, not a snapshot. The clinically useful output is the change between tests. That makes the protocol, the stimulus size, the strategy and the background luminance part of the record rather than settings left to whoever runs the machine.
It is blind to the cause. A field defect tells you where sensitivity is reduced, not why. The American Academy of Ophthalmology treats field testing as one element of glaucoma assessment rather than as a diagnosis on its own.
Is a perimeter a named device in the United States?
Yes, and the naming is unusually granular. 21 CFR 886.1605 states that "a perimeter is an AC-powered or manual device intended to determine the extent of the peripheral visual field of a patient. The device projects light on various points of a curved surface, and the patient indicates whether he or she sees the light."
The same section assigns Class I (general controls), exempts the device from the premarket notification procedures in subpart E of part 807 subject to the limitations in § 886.9, and exempts it from the quality management system regulation in part 820 except for requirements concerning records and complaint files under § 820.35.
Two further entries matter because they cover the same clinical job by a different mechanism. 21 CFR 886.1360 defines a visual field laser instrument as "an AC-powered device intended to provide visible laser radiation that produces an interference pattern on the retina to evaluate retinal function" and assigns Class II. 21 CFR 886.1810 covers the tangent screen, also known as a campimeter.
The practical reading for a buyer is that "visual field device" is not one regulatory category in the United States. Which entry applies depends on how the device produces and presents the stimulus.
Does Canada give perimeters their own device entry?
No, and the difference is structural rather than a matter of degree.
Canada classifies devices under the Medical Devices Regulations, which work from definitions and a set of rules in Schedule 1 rather than from named product lines. A perimeter is an instrument that does not contact the patient's eye and does not penetrate the body, so the invasive-device route does not reach it, and there is no Canadian entry to quote for a specification.
| Item | Canada | United States |
|---|---|---|
| Classification approach | Rules in Schedule 1 of the Medical Devices Regulations, applied to definitions | Named device entries, one per mechanism |
| Entry for a perimeter | No named entry; assessed against the general rules | 21 CFR 886.1605, perimeter |
| Entry for a laser field device | No named entry | 21 CFR 886.1360, Class II |
| Entry for a tangent screen | No named entry | 21 CFR 886.1810 |
| Assigned class for a standard perimeter | Class I for a non-invasive instrument that does not contact the eye | Class I (general controls) |
| Premarket route | Device licence at the class the rules produce; Class I is the lightest tier | Exempt from premarket notification, subject to the limits in § 886.9 |
| Instrument-level standard | ISO 12866:1999 and ISO 15004-1:2020, adopted as National Standards of Canada | The same ISO standards, plus the named entry |
On the supply side, CliniEco Medical holds Health Canada MDEL #35334 as an establishment, which is a licence to import and distribute devices in Canada. It is not a statement about any individual instrument.
Which standards govern the instrument itself?
The technical requirements are written at ISO level, and they apply on both sides of the border.
ISO 12866:1999 covers ophthalmic instruments used for perimetry, and ISO 15004-1:2020 sets the fundamental requirements that apply across ophthalmic instruments generally, including the list of instrument types it excludes from its scope. A clinic that has to evidence an instrument specification can cite both, and the ISO text is available through national standards bodies rather than only through the manufacturer.
The clinical protocol layer is separate from the instrument standard. Stimulus size, background luminance, threshold strategy and test duration are choices that change the numbers on the printout, which is why a monitoring series has to hold them constant. Two clinics running the same instrument on different strategies are not producing comparable data even though the hardware is identical.
| Item | Canada | United States |
|---|---|---|
| Instrument standard cited | ISO 12866:1999 and ISO 15004-1:2020 | The same ISO standards |
| Where the classification question is answered | Schedule 1 rules and the labelling the manufacturer files | The named entry matching the mechanism |
| Who inspects the practice | Provincial college and provincial health programmes | State boards and federal device rules |
| Notation on the record | Whatever the instrument prints, plus the protocol used | The same, and the device entry can be quoted for the instrument |
| Perimeter replacement cycle | Judgement of the practice, plus calibration records | The same |
How is field testing organised and funded in Canada?
In Ontario the funding lever is the insurance schedule. The official OHIP coverage page states that "children and youth 19 years old or younger are eligible for the following OHIP covered services: 1 major eye exam (for vision and general eye health) every 12 months; any minor assessments needed", and that adults 20 or older with an eligible medical condition affecting the eyes are covered for one major eye exam every 12 months plus two additional follow-up minor assessments. Diabetes and glaucoma appear on that list of eligible conditions.
That structure matters for field testing because field tests are usually delivered inside a monitored pathway rather than as a standalone service. The entitlement sits in the Health Insurance Act, R.S.O. 1990, c. H.6 and its detail regulation, R.R.O. 1990, Regulation 552. The College of Optometrists of Ontario's funding overview sets out how the coverage bands are drawn, the College of Optometrists of Ontario regulates practice in the province, and the Ontario eye-health library is the patient-facing layer.
Outside the clinic, field requirements also appear in licensing frameworks. Visual standards for commercial drivers sit in 49 CFR 391.41 on the US side, and the Canadian Aviation Regulations, SOR/96-433 express Canadian aviation acuity requirements in metric form. Those rules are about fitness to hold a licence rather than about a clinical service, and each has its own examiner and documentation trail.
Which consumables does a perimetry room consume?
The perimeter is the visible cost. The rest of the room is where the repeat spend sits, and it is the part a clinic can standardise.
- Examination room paper. Every field test is a seated instrument test with a chin rest and a forehead band. Smooth examination table paper is consumed at the chair, the slit lamp and the ancillary testing bench, and it is a specification purchase rather than a rounding error.
- Occlusion materials. Field testing is monocular and needs a patch or occluder the patient will leave in place for the whole test. Gauze sponges and medical tape are the items clinics already hold for improvised occlusion.
- Surface cleaning. Chin rests, forehead bands and response buttons are touched by every patient. Surface wipes are consumed on contact, and a clinic running a full field list will get through more than one per test.
- Hand hygiene and gloves. Dilated patients need drops and often a tissue, and nitrile examination gloves are consumed on contact rather than procedure.
- Documentation and consumables that cross every visit. Cotton swabs are used at the drop bottle and the lid margin, and every test needs a printed or stored printout with the protocol attached.
Sources
- 21 CFR 886.1605, perimeter
- 21 CFR 886.1605, eCFR current text
- 21 CFR 886.1810, tangent screen
- 21 CFR 886.1360, visual field laser instrument
- 21 CFR 886.1150, visual acuity chart
- ISO 12866:1999, ophthalmic instruments — perimeters
- ISO 15004-1:2020, fundamental requirements for ophthalmic instruments
- Medical Devices Regulations, SOR/98-282
- OHIP coverage, Ontario
- Health Insurance Act, R.S.O. 1990, c. H.6
- R.R.O. 1990, Regulation 552
- College of Optometrists of Ontario
- College of Optometrists of Ontario, funding options for eye examinations
- Ontario eye-health library
- AAO, glaucoma
- Canadian Ophthalmological Society
- 49 CFR 391.41, physical qualifications for drivers
- Canadian Aviation Regulations, SOR/96-433
- CCOHS, personal protective equipment
- WHO, blindness and visual impairment
Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers account setup and case pricing, and the B2B wholesale collection lists the lines stocked for institutional buyers. Clinics that also run an in-house sterilizer can start with the biological indicator 5-pack trial.
Related product: Related product: USB heated eye mask with three temperature settings (graphene heating element)
Related reading
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- Eye chart in Canada vs the US: which optotype standard
- Amsler grid in Canada vs the US: which rules apply
- Eye tests for preschoolers in Canada vs the US: which screening rules apply
- Eye masks in Canada vs the US: warm compress and dry eye
Frequently Asked Questions
Is a perimeter a regulated device in Canada?
It is a device if it meets the definitions in the Medical Devices Regulations, and it is classified by the Schedule 1 rules rather than by a named product entry. A standard perimeter does not contact the eye and does not penetrate the body, so the invasive-device rule does not reach it. The practical consequence is that a Canadian buyer cannot answer a specification question by quoting a Canadian entry, because none exists.
Why does the United States have several entries for visual field devices?
Because the entry follows the mechanism. A perimeter projects light onto a curved surface and the patient reports seeing it; a visual field laser instrument uses laser radiation to produce an interference pattern on the retina; a tangent screen is a manual campimetry target. Each is a separate identification, and the classes are not the same: the perimeter sits in Class I while the laser instrument is Class II.
What does Class I mean for a perimeter in the United States?
General controls, with relief from the premarket notification procedures in subpart E of part 807 subject to the limits in § 886.9. The perimeter entry also exempts the device from the quality management system regulation in part 820, except for the requirements concerning records and complaint files. Exemption is not the absence of regulation: labelling, record keeping and adverse-event reporting duties remain.
Can a visual field result be compared if the strategy changed?
Not reliably. Stimulus size, background luminance, threshold strategy and test duration all change the numbers, and the clinically useful output is the change between tests rather than any single printout. A monitoring series needs the protocol held constant and recorded, along with the reliability indices for each test.
Are reliability indices optional in a field test report?
They are the part of the printout that says whether the rest of it can be believed. Fixation losses, false positives and false negatives reflect how the patient performed the task rather than how the eye performed. A printout without them cannot be compared with a previous test with any confidence.
Does field testing require dilated pupils?
Not always, and the choice changes the result. Dilatation affects the peripheral field, and a series that mixes dilated and undilated tests is comparing two different conditions. Whatever the clinic chooses, the record has to say which it was, because the next test will be interpreted against it.
CliniEco Medical supplies examination room consumables, eye care lines and the wider clinic catalogue described in this article. Health Canada MDEL #35334. This article is written for clinic, laboratory and procurement professionals and is not clinical guidance; diagnostic and monitoring decisions belong to the treating practitioner.
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