(90 days)
The Keeler Applanation Tonometer is indicated for measuring intraocular pressure to aid in the screening and diagnosis of Glaucoma.
The 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 a non-active medical device and is completely mechanical, therefore without electrical components. The operation principal is based on Goldmann applanation method. The product is installed on a special support on the slit lamp and is used in conjunction with commercially available slit lamps.
Let's break down the information provided about the Keeler Applanation Tonometer (KAT) and its performance study.
Based on the provided K093445 submission, the Keeler Applanation Tonometer is a manual contact tonometer and its submission is based on substantial equivalence to predicate devices, rather than a standalone clinical study with defined acceptance criteria and specific performance metrics in the way one might see for an AI/software device. For mechanical devices like this, the 'acceptance criteria' are typically met by demonstrating that the device functions identically or equivalently to legally marketed devices, and passes relevant engineering standards.
Here's an analysis based on the provided document:
Acceptance Criteria and Device Performance
The concept of "acceptance criteria" for a diagnostic accuracy as seen in AI or complex diagnostic devices isn't directly applied here. Instead, the "acceptance criteria" are implied by substantial equivalence to predicate devices and adherence to relevant standards. The performance is assessed by comparison.
| Criterion Type | Acceptance Criteria (Implied) | Reported Device Performance (Keeler Applanation Tonometer) |
|---|---|---|
| Technological Equivalence (Bench Testing) | Device must possess comparable technological characteristics (type, indication, design, prism material, measurement range, measurement technique, measurement method, calibration, intended use) to predicate devices. Device must meet nominal requirements of Tonometer Standard BSENISO 8612:2001. The KAT has identical technological characteristics to both predicate devices (CSO F900/A900 and Haag-Streit AT 900) across all listed criteria. Bench testing verified KAT units against the nominal requirements of Tonometer Standard BSENISO 8612:2001. Comparative bench study showed KAT and predicate devices were "substantially equivalent" when subjected to the same nominal standard requirements. | |
| Clinical Equivalence (Field Trial) | Device performance in a clinical setting should be comparable to predicate devices. The field test, conducted by an ophthalmic professional, confirmed that the findings with the KAT were "comparable" to its predicate device. | |
| Safety and Effectiveness | Device is as safe and effective as predicate devices. | Based on all performance testing (bench and field), the Keeler Applanation Tonometer is "judged to be as safe, as effective and performs as well as the predicate devices." |
Study Information & Data Provenance
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a numerical sample size for patients or measurements in the provided document. The "bench testing" would involve a sample of the manufactured devices, and the "field trial" would involve some number of patients/eyes tested by an ophthalmic professional. However, specific numbers are not given.
- Data Provenance: The bench testing and field trial were likely conducted by the manufacturer or on their behalf. The country of origin of the data is implied to be within the UK (where the manufacturer is located), but this is not explicitly stated for the studies themselves. The studies appear to be prospective in nature, as they were conducted to test the performance of the new device.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not explicitly stated. The field test was conducted by "an ophthalmic professional." This implies at least one expert, but doesn't specify if it was a single individual or a group, nor are their specific qualifications (e.g., years of experience, sub-specialty) detailed.
- Qualifications of Experts: Described as "ophthalmic professional." No further detail (e.g., ophthalmologist, optometrist, specific experience) is provided.
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Adjudication method for the test set:
- Not applicable/Not explicitly stated in the context of this submission. For substantial equivalence of a general-purpose mechanical device, an adjudication method for ground truth is typically not required as it would be for a complex diagnostic algorithm. The comparison is against established, legally marketed devices.
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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:
- No, an MRMC comparative effectiveness study was not done. This type of study is specifically relevant to evaluating AI (artificial intelligence) systems or other diagnostic aids where human interpretation is assisted. The Keeler Applanation Tonometer is a purely mechanical device, not an AI system. Therefore, this question is not applicable.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- No. This question is also not applicable as the Keeler Applanation Tonometer is a manual, mechanical device and does not involve an algorithm or AI. Its operation inherently requires a human operator ("manual contact tonometer").
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the bench testing, the "ground truth" was adherence to the Tonometer Standard BSENISO 8612:2001 and direct comparison of measurements against the predicate devices.
- For the field trial, the "ground truth" was likely the intraocular pressure (IOP) readings obtained by the "ophthalmic professional" using both the Keeler Applanation Tonometer and the predicate device(s) on actual patients, with comparability being the key outcome. It's not based on pathology or outcomes data in the sense of disease progression, but on the agreement of the measurement value itself.
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The sample size for the training set:
- Not applicable. The Keeler Applanation Tonometer is a mechanical device, not a machine learning model. Therefore, it does not have a "training set."
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How the ground truth for the training set was established:
- Not applicable. As there is no training set, there is no ground truth for a training set.
§ 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.