Quick facts
- A Bagolini lens is a plane lens carrying almost imperceptible striations that do not obscure what the patient sees; it is placed in a trial frame.
- In the United States it files under 21 CFR 886.1375, Bagolini lens, at Class I, product code HPD.
- Canada keeps no named entry. The lens is a passive optical element that supplies no energy, so Rule 7(1) of Schedule 1 keeps it at Class I.
- The near miss is Rule 10(1), the active diagnostic rule, which does not apply because the lens contains no light source and delivers no energy to the patient.
- A second near miss is Rule 7(2)(a): a device that acts as a calibrator, tester or quality-control support to another device is Class II, but a striated test lens is the target the patient looks through, not a check on another device.
- Entries, classes and product codes below were checked against the eCFR, the Regulations and the openFDA classification database on 2026-10-14.
A Bagolini lens is a plain lens ruled with fine striations that leave what the patient sees almost untouched. Worn in a trial frame, one before each eye, the striations turn a point of light into a line, and the patient reports what the two lines do — which is how harmonious and anomalous retinal correspondence are told apart. The United States names the lens at Class I; Canada reaches the same class through the passive-device rule, and this article sets out why two tempting rules do not apply, with the smooth disposable bed sheets the test room keeps under the chair.
What is a Bagolini lens and what is it used for?
It is a device that consists of a plane lens containing almost imperceptible striations that do not obscure visualization of objects. The striations run at an angle across the lens, so a small light source viewed through it is drawn out into a line whose direction follows the striations. Placed in a trial frame, one before each eye and set at an angle to each other, the two lines give the clinician a picture of how the two eyes are being used together.
The instrument is deliberately close to invisible: the point of the low-contrast striations is that the patient still sees the room normally and is not prompted to change fixation. The result is read from the patient's report of where the two lines sit relative to each other, so the record keeps the orientation used and the patient's described view.
What class is a Bagolini lens in the United States?
It is a named entry at Class I. 21 CFR 886.1375 is titled Bagolini lens, and the identification reads: "A Bagolini lens is a device that consists of a plane lens containing almost imperceptible striations that do not obscure visualization of objects. The device is placed in a trial frame and intended to determine harmonious or anomalous retinal correspondence." Like the neighbouring ophthalmic entries, it is exempt from the premarket notification procedures and from most of the quality management system requirements of part 820.
The openFDA device classification API lists product code HPD against 886.1375. The Class I placement reflects the risk of the article: it is an optical element held in front of the eye, it is not implanted, it does not touch the globe, and it introduces no energy into the eye.
| Item | Detail |
|---|---|
| US regulation | 21 CFR 886.1375 - Bagolini lens |
| US class | Class I (general controls) |
| Product code | HPD |
| Route to market | Exempt from premarket notification under subpart E of part 807; exempt from part 820 except records and complaint files |
| Intended use | To determine harmonious or anomalous retinal correspondence |
| Form | Plane lens with fine striations, held in a trial frame |
How does Canada classify a Bagolini lens?
Canada keeps no named entry, so the class comes from the rules in Schedule 1 of the Medical Devices Regulations. The first question is whether the lens is invasive. It is held in a trial frame in front of the eye and does not enter a body orifice or touch the surface of the eye, so it is a non-invasive device and Rule 7(1) applies: "Subject to subrule (2), all other non-invasive devices are classified as Class I."
Two near misses are worth naming, because each is a rule a reader may reach for. Rule 10(1) sets an active diagnostic device that supplies energy at Class II; a Bagolini lens is a passive optical element with no light source of its own, so the rule does not capture it. Rule 7(2)(a) lifts a non-invasive device to Class II if it is intended to act as a calibrator, tester or quality-control support to another medical device; a striated lens is the target the patient looks through rather than a check on another device, so this rule does not capture it either.
| Item | Canada | United States |
|---|---|---|
| Named entry | None; classified by rule | 886.1375 - Bagolini lens |
| Class | Class I (Rule 7(1), non-invasive) | Class I (general controls) |
| Governing text | Schedule 1, Part 1, Rule 7(1) | 21 CFR 886.1375 |
| Rule 10(1) applies? | No; the lens supplies no energy | Not applicable |
| Rule 7(2)(a) applies? | No; the lens is not a tester for another device | Not applicable |
Why does the passive-versus-active line matter so much?
Because in both systems the classification hinges on whether the device does something to the patient. An active device supplies or withdraws energy; a passive optical element does not. A Bagolini lens is on the passive side of that line, and the line is drawn in the same place in each jurisdiction, which is why the two answers agree.
The comparison with an active ophthalmic instrument makes the point. A retinoscope, an ophthalmoscope or a projector throws light into the eye and is read against the active rules; a striated lens, a trial frame and a prism bar are read against the non-invasive rules. Reading the device before reading its name is what keeps the class right.
The same line runs through the trial-frame drawer. A trial frame, a Maddox lens, a prism bar and a Bagolini lens are all passive optical elements held in front of the eye, and each is placed by the non-invasive default rather than by an energy rule. The test differs from one to the next; the classification logic does not.
What should a clinic check before ordering one?
Three checks. First, confirm the striation orientation and that the lens is supplied as a matched pair, because the test depends on the two lines being set at a known angle to each other. Second, confirm the maker's cleaning routine, since the lens is handled close to the eye and is reused. Third, confirm the frame the clinic will hold it in, because a Bagolini lens is a lens blank rather than a finished instrument and is only useful when it seats properly in a trial frame.
An eye clinic also restocks the bench consumables used during the binocular-vision work-up. 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 single-use specimen cups sits in the same catalogue. Reselling? become a distributor.
Does the class change how the test is recorded?
No. The class sets the market-entry path, not the clinical record. A binocular-vision work-up is recorded with the test used, the orientation of the striations, whether the trial was done at distance or near, and what the patient reported, so a repeat test can be compared with the first when the question is whether the sensory status has changed.
Because the result is what the patient reports, the routine also depends on clear instruction and on controlled room lighting. That is ordinary practice for a patient-contact diagnostic service, and it holds whatever the class of the lens turns out to be.
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 17664:2017, processing of health care products, information to be provided
- 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 blank page for the binocular-vision file. The four lines a correspondence test has to hold — test used, striation orientation, test distance and the response — fit on a single sheet you can print and staple behind the chart. The compliance log centre holds the blank version; there is no account and no sign-up, and you can print as many as the week needs.
Say the columns once, get a dated sheet back. Enter the practice name, the trial-frame serial and the test protocol, and the sterilization log generator returns a laid-out dated page you can print or keep in the quality manual.
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
- Maddox lenses in Canada vs the US
- Ophthalmic stereopsis tests in Canada vs the US
- Diplopia prisms and low-vision aids 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 a Bagolini lens in the United States?
Class I under 21 CFR 886.1375, product code HPD, exempt from premarket notification subject to the limits of section 886.9.
What class is it in Canada?
Class I, under Rule 7(1) of Schedule 1 of the Medical Devices Regulations, which is the default for non-invasive devices.
Does the active-diagnostic rule apply to it?
No. Rule 10(1) reaches active devices that supply energy to image or monitor a physiological process. A Bagolini lens is a passive optical element with no light source.
Why is it not read as a tester under Rule 7(2)(a)?
Because that subrule reaches a non-invasive device that acts as a calibrator, tester or quality-control support to another medical device. A striated lens is the target the patient looks through, not a check on another device.
Do the two countries agree?
On the class, yes — both answer Class I. The United States has a named entry; Canada derives the class from the non-invasive rule.
Is a Bagolini lens the same as a Maddox lens?
No. Both dissociate the two eyes, but a Maddox lens uses a red cylinder to turn a light point into a line for one eye, while a Bagolini lens uses near-invisible striations that leave the view almost undisrupted.
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