(90 days)
This instrument is used for measuring the axial length, anterior chamber depth and lens thickness of the eye. It also is used for calculating the optical power of the IOL to be implanted during cataract surgery.
The Accutome A-Scan Plus Connect device is designed as a biometer, which uses pulsed echo ultrasound to measure the axial length, and the location of other structures of the eye. It utilizes an eye-contact probe to generate and receive the ultrasound pulses, and provides a one-dimensional display of returning pulse echoes, with positive peaks to indicate the location of ocular structures. The distance between peaks can be measured.
The new A-Scan Plus Connect model uses the personal computer as the main computing vehicle and display instead of the dedicated computer/display of the predicate device. The software modifications in the Connect model are those necessary to interface the processing, data storage, display, and printing capabilities of the personal computer.
The A-Scan Plus connect control unit is an interface between the ultrasonic probe and a personal computer. It consists of a microprocessor based printed circuit board, with USB connections, enclosed in a plastic case.
The energy source for the A-Scan Plus Connect is USB power from the personal computer instead of the AC to DC adapter used to power the predicate device.
Here's a summary of the acceptance criteria and study details for the Accutome A-Scan Plus Connect, based on the provided document:
Acceptance Criteria and Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Physical Accuracy Test: Device measurement within 0.1mm of physical distance. | Both the A-Scan Plus Connect and the predicate device were well within the 0.1mm acceptance criteria. |
| Data Comparison Test (Accusonic A-Scan vs. A-Scan Plus Connect): |
- Ultrasound measurements for all eye types within 0.05mm.
- IOL calculation results for all formulas within one decimal place. | All of the data met the established acceptance criteria:
- Ultrasound measurements for all eye types were within 0.05mm.
- IOL calculation results for all formulas were within one decimal place. |
| Internal Validation Tests: All operations and features fully functional, no errors or deficiencies in patient information, and usability deemed superior to the predicate device. | All operations and features were fully functional. There were no errors or deficiencies in the patient information. The usability was judged to be superior to the predicate device. |
| External Validation Tests: Safety, functionality, and usability evaluated with a rating scale (1-5, 5=best). No ratings of 1 or 2 in any tests, with a high average rating for specific attributes and an overall rating of 5. | Safety was ranked 5 by every user. The average rating for the 9 specific attributes enumerated was 4.8. The "Overall Rating" of the device was 5 by all users. There were no ratings of 1 or 2 in any of the tests. |
Study Details
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Sample size used for the test set and the data provenance:
- Physical Accuracy Test: Not explicitly stated, but implies a comparison of measurements from a test fixture.
- Data Comparison Test: Not explicitly stated, but involved measuring "all eye types" and performing "all formulas" for IOL calculations on an input test fixture.
- Internal Validation Tests: The test plan consisted of 83 specific evaluations, most requiring multiple actions/observations. The sample size refers to the number of evaluations rather than patient data.
- External Validation Tests: 29 different patients were evaluated. The data provenance is not explicitly stated in terms of country of origin, nor is it specified as retrospective or prospective, though the nature of "evaluating patients" suggests a prospective approach.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- External Validation Tests: 3 different experienced technicians/ophthalmologists. Their specific qualifications (e.g., years of experience) are not detailed beyond "experienced." One user had detailed experience with the predicate device, and two with a competitive biometer.
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Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- No adjudication method is described for resolving discrepancies, as the criteria were based on ratings given by users.
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If a multi-reader, multi-case (MRMC) comparative effectiveness study was done:
- No, a formal MRMC comparative effectiveness study as typically understood in AI/medical imaging (comparing reader performance with and without AI assistance) was not done. The external validation involved multiple users but focused on device usability and functionality relative to a predicate, rather than comparing human reader diagnostic accuracy with and without AI.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- The "Physical Accuracy Test" and "Data Comparison Test" can be considered standalone algorithm performance tests, as they directly compare the device's measurements and calculations to physical standards or expected outputs from a test fixture, without direct human input into the measurement generation.
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The type of ground truth used:
- Physical Accuracy Test: Physical distance measured by a mechanical dial indicator.
- Data Comparison Test: Established criteria for ultrasound measurements (within 0.05mm) and IOL calculation results (within one decimal place) based on a test fixture.
- Internal Validation Tests: Proper operation and usability, validated against the defined test plan and expected performance.
- External Validation Tests: User ratings from experienced technicians/ophthalmologists regarding safety, functionality, and usability.
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The sample size for the training set:
- The document does not describe a training set for the A-Scan Plus Connect itself, as it is presented as having "software algorithms for clinically critical functions... exactly the same as in the predicate device." Therefore, it's not a new algorithm requiring a separate training set.
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How the ground truth for the training set was established:
- Not applicable, as no new training set for the A-Scan Plus Connect is described. The device's clinical critical functions are based on algorithms identical to the predicate device.
§ 892.1560 Ultrasonic pulsed echo imaging system.
(a)
Identification. An ultrasonic pulsed echo imaging system is a device intended to project a pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and to measure the duration of an acoustic pulse from the transmitter to the tissue interface and back to the receiver. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). A biopsy needle guide kit intended for use with an ultrasonic pulsed echo imaging system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.