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The LENSTAR LS 900 is a non-invasive, non-contact OLCR (Optical Low Coherence Reflectometry) Biometer used for obtaining ocular measurements and performing calculations to assist in the determination of the appropriate power and type of IOL (intraocular lens) for implantation after removal of the natural crystalline lens following cataract removal. The LENSTAR LS 900 measures:

• Axial eye length
• Corneal thickness
• Anterior chamber depth
• Aqueous depth
• Lens thickness
• Radii of curvature of flat and steep meridian
• Axis of the flat meridian
• White to white distance
• Pupil diameter

The LENSTAR LS 900 is a non-invasive, non-contact system for measuring the parameters of the human eye required to determine the appropriate IOL for implantation and to calculate the optimal power of the IOL. The LENSTAR LS 900 measures: axial eye length, corneal thickness, anterior chamber depth, lens thickness, radii of curvature of flat and steep meridian, axis of flat or step meridian, white to white distance and pupil diameter.

Acceptance Criteria and Device Performance for LENSTAR LS 900

This report details the acceptance criteria and the study conducted to demonstrate the substantial equivalence of the Haag-Streit LENSTAR LS 900 to predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

The provided document doesn't explicitly state quantitative acceptance criteria for the LENSTAR LS 900. Instead, it focuses on demonstrating "substantive equivalence" to existing, legally marketed predicate devices through a comparison of measurement data. The "acceptance criteria" can therefore be inferred as demonstrating a high degree of statistical correlation or agreement in measurements between the LENSTAR LS 900 and the predicate devices.

2. Sample Size and Data Provenance

• Sample Size for Test Set: The document does not specify the exact sample size for the test set of patients used in the clinical studies. It only states that "Two prospective, non-randomized, single site comparison studies were performed."
• Data Provenance: The studies were conducted in Berne, Switzerland. The data is prospective, as indicated by "Two prospective... studies were performed."

3. Number of Experts and Qualifications for Ground Truth

The document does not specify the number of experts used to establish ground truth or their qualifications. The study design primarily focuses on comparing measurements obtained by the LENSTAR LS 900 with those from established predicate devices. The "ground truth" for the test set is effectively derived from the measurements produced by these predicate devices.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for the test set. The clinical summary indicates "comparison studies" were performed, meaning the data from the LENSTAR LS 900 was directly compared to the measurements from the predicate devices.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, an MRMC comparative effectiveness study was not done. The studies described are focused on the equivalence of device measurements, not on the improvement of human reader performance with AI assistance. The LENSTAR LS 900 is a measurement device, not an AI-assisted diagnostic tool for human readers in the typical sense of an MRMC study.

6. Standalone Performance Study (Algorithm Only)

Yes, a standalone performance study was done implicitly. The clinical studies evaluated the LENSTAR LS 900's ability to measure various ocular parameters independently and then compared these measurements to those obtained by predicate devices. This constitutes a standalone performance evaluation in terms of its ability to produce measurements, even if the "algorithm" is inherent to the optical low coherence reflectometry technology itself rather than a distinct AI algorithm. The performance of the device's measurements was compared directly without human interpretation of its outputs in the validation.

7. Type of Ground Truth Used

The "ground truth" for the comparison studies was derived from the measurements obtained by legally marketed predicate devices. This means that the established and accepted accuracy of these existing devices (IOL-Master, OLCR, Accusonic A-Scan, Keratron) served as the reference for determining the equivalence of the LENSTAR LS 900's measurements.

8. Sample Size for the Training Set

The document does not mention a separate "training set" or its sample size. This is expected as the LENSTAR LS 900 is based on established optical principles (Optical Low Coherence Reflectometry) and does not describe a machine learning algorithm requiring a distinct training phase. Its development would involve engineering and calibration, not traditional machine learning training.

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

As there is no mention of a training set for a machine learning algorithm, there is no corresponding description of how ground truth for a training set was established. The device relies on physical principles and instrument calibration rather than data-driven learning for its primary function.

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Collectively, the 3 PalmScan 2000 Devices [i.e., three (3) biometric devices listed below] are each designed as either: a) the PalmScan AP2000 A-Scan/Pachymeter Combination dual mode device [i.e., PalmScan AP2000]; or solely as: b) the PalmScan A2000 A-Scan mode only device [i.e., PalmScan A2000); or as: c) the PalmScan P2000 Pachymeter mode only [i.e., PalmScan P2000] medical device.

The PalmScan AP2000 A-Scan/Pachymeter Combination [i.e., PalmScan AP2000] device is intended as a portable battery operated biometer, which incorporates A-mode pulsed-echo ultrasound technology, and thus is intended be used to accurately measure the axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and corneal thickness (CT) of the human eye. This PalmScan AP2000 device is also intended for calculating the optical power of an intraocular lens (IOL) that is to be implanted during cataract surgery.

The PalmScan A2000 A-Scan [i.e., PalmScan A2000] device is intended as a portable battery operated biometer, which incorporates A-mode pulsedecho ultrasound technology, and thus is intended be used to accurately measure the axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) of the human eye. This PalmScan A2000 device is also intended for calculating the optical power of an intraocular lens (IOL) that is to be implanted during cataract surgery.

The PalmScan P2000 Pachymeter [i.e., PalmScan P2000] device (as well as the combination PalmScan AP2000 device) is intended as a potable battery operated pachymeter, which incorporates A-mode pulsed-echo ultrasound technology, and thus is intended be used to accurately measure the corneal thickness (CT) of the human eye.

The PalmScan AP2000 A-Scan/Pachymeter Combination [i.e., PalmScan AP2000] device is a portable, battery operated biometer, which uses A-Mode, pulsed-echo ultrasound technology to measure the axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and corneal thickness (CT) of the human eye. This PalmScan AP2000 device utilizes a Palm Personal Digital Assistant (Palm PDA) for user interface, information display, as well as data processing. This PalmScan AP2000 device non-sterile professional use only device also utilizes a contact and/or immersion ultrasonic transducer to generate pulses and receive their echoes.

The PalmScan A2000 A-Scan [i.e., PalmScan A2000] device is a portable, battery operated biometer, which uses A-Mode, pulsed-echo ultrasound battory operator the axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) of the human eye. This PalmScan A2000 (100), altilizes a Palm Personal Digital Assistant (Palm PDA) for user interface, information display, as well as data processing. This PalmScan A2000 device non-sterile professional use only device also utilizes a contact and/or immersion ultrasonic transducer to generate pulses and receive their echoes.

The PalmScan P2000 Pachymeter [i.e., PalmScan P2000] device is a portable, battery operated biometer, which uses A-Mode, pulsed-echo ultrasound technology to measure the corneal thickness (CT) of the human eye. The PalmScan P2000 device utilizes a Palm Personal Digital Assistant (Palm PDA) for user interface, information display, as well as data processing. This PalmScan P2000 device non-sterile professional use only device also utilizes a contact and/or immersion ultrasonic transducer to generate pulses and receive their echoes.

Acceptance Criteria and Device Performance for PalmScan AP2000, A2000, and P2000 Devices

The acceptance criteria for the PalmScan AP2000, A2000, and P2000 devices are primarily based on their accuracy in measuring various ophthalmic parameters (Axial Length, Anterior Chamber Depth, Lens Thickness, and Corneal Thickness) and ensuring their safety for use. The study demonstrates that the devices meet these criteria through both phantom testing and comparison with established methods.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly established by demonstrating performance comparable to the predicate device (DGH 4000) and within specified tolerances for clinical measurements.

Safety Acceptance Criteria:

• Acoustic Power Output: Must be below limits set by FDA guidance ("Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers", FOD #560, Sept. 30, 1997) and meet IEC 60601-1-1 standard.
  • PalmScan AP & A2000 (A-Scan): ISPTA.3 = 0.419 mW/cm², ISPPA.3 = 0.795 W/cm² (Below DGH A-Scan: ISPTA.3 = 1.66, ISPPA.3 = 2.76)
  • PalmScan AP & P2000 (Pachymeter): ISPTA.3 = 0.088 mW/cm², ISPPA.3 = 0.29 W/cm² (Below DGH Pachymeter: ISPTA.3 = 7.47, ISPPA.3 = 12.0)
• Biocompatibility: Ocular contact tips must be non-irritating and safe for human ocular tissues (ISO 10993-10:1995).
  • Performance: The contact tips (Polystyrene for Pachymeter, Epoxy for A-Scan) were shown to be non-irritating and completely safe.
• Measurement Hazards (e.g., Digital Clock Error, Hardware Failure): Minor level of concern due to implemented controls and corrective measures.
  • Performance: High precision oscillators used to minimize drift and aging errors. Self-test sequence, pattern recognition algorithms, and user review of waveforms/statistical analysis of data are in place to mitigate hardware-related measurement errors.

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

• A-Scan Mode:
  • Phantom Test: "multiple measurements were taken from the DGH phantom" (exact number not specified).
  • Human Eye Comparison: Four human eyes were used for comparison against a laser interferometer method (Zeiss IOL Master device).
  • Data Provenance: The phantom was purchased from DGH Corporation (presumably US-based). The human eye data provenance (country, retrospective/prospective) is not explicitly stated, but the comparison implies prospective data collection for the purpose of this study.
• Pachymeter Mode:
  • Phantom Test: "tested extensively with a pachymeter eye phantom" (exact number of measurements not specified).
  • Human Eye Comparison: "confirmed by comparison studies in human eyes against a high precision Pachymeter" (exact number of human eyes not specified).
  • Data Provenance: The pachymeter eye phantom was created in-house. The human eye data provenance (country, retrospective/prospective) is not explicitly stated.

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

The document does not explicitly state the number of experts used to establish the ground truth or their specific qualifications for the human eye comparison studies.

• For the A-Scan human eye comparison, the "laser interferometer method (using the Zeiss IOL Master device)" is described as "considered a gold standard in axial length measurement by ophthalmologists." This implies that the ground truth was established by a widely accepted and validated clinical method, likely operated by qualified ophthalmologists or technicians.
• For the Pachymeter human eye comparison, it was "confirmed by comparison studies in human eyes against a high precision Pachymeter."

4. Adjudication Method for the Test Set

The document does not describe a formal adjudication method (e.g., 2+1, 3+1 consensus) for the test set. For the human eye studies, the comparison was made against established "gold standard" devices/methods, implying these methods provided the reference values for accuracy assessment.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was mentioned in the provided text. The studies described focus on the standalone performance of the device and its comparison to other devices/phantoms, not on human readers' performance with and without AI assistance.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, a standalone performance study was done for the device itself.

• A-Scan Mode: The devices were "tested extensively with eye phantoms." The DGH eye phantom was "calibrated to measure an aphakic eye of 24.1 ± 0.25 mm." Multiple measurements were taken from this phantom in aphakic data capture mode.
• Pachymeter Mode: The devices were "tested extensively with a pachymeter eye phantom." This phantom, created in-house, had its delay circuit measured using a calibrated Oscilloscope. The PalmScan devices were then tested in Pachymeter mode against this phantom.
• Human Eye Comparisons: The devices also performed measurements on human eyes which were then compared to reference measurements obtained from "gold standard" devices, indicating standalone performance validation.
• Accuracy calculations: Table G provides accuracy calculations based on physical parameters of the device (speed of sound, sampling rate), implying an inherent, standalone performance metric.

7. The Type of Ground Truth Used

• Phantom Testing: The ground truth for phantom testing was established by the known, calibrated values of the eye phantoms.
  • For A-Scan, it was a "DGH phantom... calibrated to measure an aphakic eye of 24.1 ± 0.25 mm".
  • For Pachymeter, it was an "eye phantom... created in house using a fixed delay circuit" whose delay was "first measured using a calibrated Oscilloscope".
• Human Eye Comparison: The ground truth for human eye measurements was established by "laser interferometry" (specifically the Zeiss IOL Master device, which is considered a "gold standard in axial length measurement by ophthalmologists") for A-Scan, and by a "high precision Pachymeter" for the Pachymeter mode.

8. Sample Size for the Training Set

The document does not specify a training set or its sample size. The description of the device's "Pattern recognition program" for A-Scan implies some form of algorithm or model development, but details regarding a separate training set, if any, are not provided. The term "training set" is typically associated with machine learning models; this document describes a traditional ultrasonic device.

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

As no explicit training set is identified, the method for establishing its ground truth is not provided. The device's "A-Scan Pattern recognition program" likely relies on pre-defined ultrasonic principles and signal processing, rather than being "trained" on a dataset in the modern machine learning sense.

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