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The Nidek ECHOSCAN Model US-1800 is a diagnostic instrument that is intended for use in the measurement of the axial length of the eye and corneal thickness.

The EchoScan Model US-1800 is a diagnostic instrument that is indicated for use in the measurement of the axial length of the eye and corneal thickness.

The instrument is used to measure the axial length of the eye and the thickness of the cornea by the application of an ultrasound pulse reflection method. During axial length measurement, the cornea is touched with a probe, and the ultrasonic pulse sent by the transducer in the probe is reflected within each part of the eye (cornea, anterior chamber, lens, vitreous body, retina, etc.) and their echoes are received by the same probe. The received echoes are converted to electronic acoustic signals and indicated on the LCD as an amplitude. In addition, the time difference of each echo is measured and the length of each tissue (AC depth, lens thickness, vitreous body length, and axial length) is calculated according to the time difference and known inherent sonic velocity of each tissue.

For corneal thickness measurement, the ultrasonic pulses are transmitted when the probe is put on the cornea. Part of the pulses are reflected and the front and rear surface of the cornea. When the probe receives the reflected echoes, the time difference of each echo is measured and the corneal thickness is calculated according to the time difference and known inherent sonic velocity of the cornea.

Here's an analysis of the Nidek ECHOSCAN Model US-1800 acceptance criteria and performance study based on the provided text, structured to answer your specific questions:

The document provided is a 510(k) summary for the Nidek ECHOSCAN Model US-1800, which is a submission to the FDA to demonstrate substantial equivalence to a predicate device. As such, the "acceptance criteria" discussed are primarily focused on demonstrating that the new device shares fundamental technological characteristics with, and is as safe and effective as, its predicate. This is not a clinical trial report with predetermined performance metrics for a novel AI algorithm. Instead, it's a comparison to an already cleared device.

1. Table of Acceptance Criteria and Reported Device Performance

Note: The term "acceptance criteria" in this context refers to the technological specifications and performance characteristics that the new device (US-1800) must meet to be considered substantially equivalent to the predicate device (US-2000). The "reported device performance" is how the US-1800 measures up against these established characteristics of the predicate, or to relevant standards.

2. Sample Size Used for the Test Set and Data Provenance

The provided document is a 510(k) summary focused on demonstrating substantial equivalence through technological comparison and compliance with standards. It does not describe a clinical study with a test set of patient data. Instead, the "testing" performed was:

• Electrical Safety Testing: In accordance with EN 60601-1 and EN 60601-1-2.
• Programmable Electrical Medical Systems testing: In accordance with EN 60601-1-4.
• Acoustic Output Test Measurements: In accordance with the Acoustic Output Measurement Standard for Diagnostic Ultrasound Equipment (May 1998).

Therefore, there is no patient-based test set or associated sample size, or data provenance (e.g., country of origin, retrospective/prospective) mentioned in this document. The "tests" were device-centric against engineering and safety standards.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

As there was no patient-based clinical "test set" and no "ground truth" derived from patient data in the context of diagnostic accuracy, this information is not applicable to this document. The "ground truth" for the engineering performance tests would be the established values and limits within the specified international standards (EN 60601-1, EN 60601-1-2, EN 60601-1-4, and the Acoustic Output Measurement Standard). The experts involved would be the test engineers performing the measurements and verifying compliance with these standards.

4. Adjudication Method for the Test Set

Since there was no patient-based clinical "test set" requiring interpretation or consensus among experts for ground truth, an adjudication method like 2+1 or 3+1 is not applicable. The "adjudication" was based on whether the device's measured performance met the technical specifications and safety limits defined by the referenced standards.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done

No, an MRMC comparative effectiveness study was not done. The document is a 510(k) summary focusing on demonstrating substantial equivalence based on technological characteristics and compliance with safety standards, not a clinical study comparing the diagnostic performance of human readers with and without AI assistance. This device is an ultrasound measurement instrument, not an AI-powered diagnostic image interpretation tool.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done

This is not applicable. The Nidek ECHOSCAN Model US-1800 is a diagnostic ultrasound instrument that performs measurements (not an AI algorithm that renders a diagnostic interpretation). Its "performance" is its ability to accurately measure axial length and corneal thickness, which are direct physical measurements, not AI-driven interpretations. The intrinsic accuracy of these measurements (±0.1mm for axial length, ±5µm for corneal thickness) is a standalone performance metric for the device, but it's not an AI algorithm.

7. The Type of Ground Truth Used

For the performance metrics listed (e.g., Clinical Accuracy ± 0.1 mm, Accuracy ± 5 µm), the "ground truth" implicitly refers to the physical accuracy of the measurement when compared against a known standard or highly precise reference measurement. This is standard metrological practice, not expert consensus, pathology, or outcomes data in the clinical diagnostic sense. For the other tests (electrical safety, EMC, acoustic output), the "ground truth" is compliance with the limits and requirements set forth in the specific international and acoustic measurement standards referenced (EN 60601-1, EN 60601-1-2, EN 60601-1-4, and the Acoustic Output Measurement Standard for Diagnostic Ultrasound Equipment).

8. The Sample Size for the Training Set

Not applicable. This document describes a medical device, not an AI/machine learning algorithm. Therefore, there is no "training set" in the context of machine learning.

9. How the Ground Truth for the Training Set Was Established

Not applicable. As there is no AI algorithm and no training set, this question does not apply.

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