(123 days)
The Keeler Applanation Tonometer is indicated for measuring intraocular pressure to aid in the screening and diagnosis of Glaucoma.
The Digital Keeler Applanation Tonometer is a screening device used to measure intraocular pressure which is one of the factors considered in diagnosing glaucoma. The product is an active medical device, powered by a single AA battery. The operation principal is based on Goldmann applanation method.
The provided document describes the modification of a Keeler Applanation Tonometer (KAT) to a Digital Keeler Applanation Tonometer (D-KAT). The D-KAT is intended to provide a digital readout of intraocular pressure (IOP) as an alternative to the manual dial reading of the predicate device.
Acceptance Criteria and Reported Device Performance
The primary acceptance criterion described for the D-KAT is its measurement deviation, which is based on the Tonometer standard ISO 8612:2009. The device needs to achieve a measurement deviation comparable to the predicate device.
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Measurement Deviation: ±0.49 mN (~0.5mmHg) or 1.5% of measurement value, whichever is greater (in accordance with ISO 8612:2009) | The D-KAT instrument has been validated to a measurement deviation of ±0.49mN (~0.5mmHg) or 1.5%, whichever is greater, in accordance with ISO 8612:2009. |
| Compliance with IEC 60601-1 (Electrical Safety) | Device has been tested to meet IEC 60601-1 Electrical Safety requirements. |
| Compliance with IEC 60601-1-2 (EMC) | Device has been tested to meet IEC 60601-1-2 EMC requirements. |
| Software designed and developed in accordance with ISO 62304 | The software has been designed and developed in accordance with ISO 62304 Medical device software - Software life-cycle processes. |
| Essential requirements and test methods for ophthalmic instruments (ISO 15004-1) | Assessed and/or tested to ISO 15004-1:2006. |
| Symbols to be used with medical devices (ISO 15223-1) | Assessed and/or tested to ISO 15223-1:2012. |
| Biological evaluation of medical devices (ISO 10993-1) | Assessed and/or tested to ISO 10993-1. |
| Risk management (ISO 14971) | Assessed and/or tested to ISO 14971:2007. |
Study Details:
The provided document describes verification tests and compliance with various standards to demonstrate substantial equivalence to the predicate device, rather than a clinical study with human readers and AI.
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a number of patients or cases. The performance validation was conducted through "bench testing using a balance system" and "usability tests."
- Data Provenance: Bench testing would be laboratory data. Usability tests were conducted by healthcare professionals, implying an in-situ or simulated clinical environment. No specific country of origin is mentioned for the data, but the manufacturer is Keeler Instruments Inc. in the USA. The data is likely prospective for these validation tests.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- For the bench testing, the "ground truth" was established by applying "known pressures covering the measurement range" using calibration bars verified according to ISO 8612:2009. This relies on the accuracy of the calibration system rather than human experts.
- For the usability tests, "healthcare professionals" were involved, but their number and specific qualifications (beyond being healthcare professionals) are not detailed. Their role was to compare the D-KAT against the predicate device, not necessarily to establish ground truth for IOP measurements.
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Adjudication method for the test set: Not applicable. The primary performance evaluation was bench testing against a standard, not a scenario requiring adjudication between human readers or device outputs.
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If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance: Not applicable. This document describes a medical device (tonometer) with a digital display, not an AI-powered diagnostic tool requiring MRMC studies to compare human reader performance with and without AI assistance.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: The device itself is an "algorithm only" in the sense that the software processes the raw measurement to display the IOP. The "bench testing using a balance system" is a form of standalone performance evaluation for the device's accuracy in measuring force/pressure, conforming to the ISO standard.
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The type of ground truth used:
- For measurement performance: The "known pressures" provided by a calibrated balance system, verified against ISO 8612:2009.
- For usability: Comparison against the predicate device by healthcare professionals. No objective "ground truth" for usability is described, rather a subjective comparison.
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The sample size for the training set: Not applicable. The device is a measurement instrument, not an AI model that requires a training set in the conventional sense. The "software uses information stored / programmed during the factory setup / calibration" which could be considered akin to a "training" or calibration phase, but it's not a data-driven machine learning training set.
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How the ground truth for the training set was established: Not applicable, as there is no training set in the typical machine learning context. The calibration information for the device's setup is established during "factory setup / calibration" by applying "known pressures" and relating them to the rotating measuring drum's position, as outlined in ISO 8612:2009.
§ 886.1930 Tonometer and accessories.
(a)
Identification. A tonometer and accessories is a manual device intended to measure intraocular pressure by applying a known force on the globe of the eye and measuring the amount of indentation produced (Schiotz type) or to measure intraocular tension by applanation (applying a small flat disk to the cornea). Accessories for the device may include a tonometer calibrator or a tonograph recording system. The device is intended for use in the diagnosis of glaucoma.(b)
Classification. Class II.