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The Retinal Functional Imager (RFI) is intended to observe, capture, display, and store images of patients' fundus (retina) under mydriatic conditions to aid in diagnosing or monitoring diseases of the eye that may be observed and photographed.

The modified RFI, like the cleared RFI, is a mydriatic fundus imaging camera intended for taking red-free images. The modified RFI, as the cleared device, comprises of the following sub-assemblies:

• An optical system for illuminating and imaging the retina. The optical imaging includes a stroboscopic light source for sequential rapid imaging of the retina.
• A high resolution CCD camera.
• An electronic unit for driving the light source.
• A software package for operating the system, controlling the illumination, grabbing the images, data browsing and data analysis.
  The device is also capable of using 35 mm film or using a digital camera similar to the predicate devices. Visible light is used for observation. Alignment and focusing is manual via the fundus camera controls.
  Under red-free imaging, the modified RFI provides, through a series of multiple flashes, the ability to observe and register the blood flow velocity and path of motion.

The Retinal Functional Imager 3000 (RFI 3000) is intended to observe, capture, display, and store images of patients' fundus (retina) under mydriatic conditions to aid in diagnosing or monitoring diseases of the eye. The device provides information on blood flow (velocity) and path of flow in retinal vessels, but its repeatability and trueness for retinal blood flow velocity measurements have not been clinically established.

Here's an analysis of the provided information regarding acceptance criteria and performance studies:

1. Acceptance Criteria and Reported Device Performance

The device's performance was evaluated through bench testing using a model eye simulation. The key metrics assessed were repeatability (standard deviation of repeated measurements) and accuracy (measured versus calculated results) of retinal blood flow velocity (RBFV) measurements. While specific acceptance criteria are not explicitly stated as numerical thresholds (e.g., "SD must be < X" or "Accuracy must be within Y%"), the study aims to characterize these performance aspects.

Here's a table summarizing the reported device performance:

Table: Bench Repeatability and Accuracy of Retinal Blood Flow Velocity Measurements

Note: The document states that "repeatability and trueness of the retinal blood flow velocity measurement has not been established clinically." The performance data presented above are from bench testing.

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

• Sample Size for Test Set: The "test set" for the RBFV measurements consisted of repeated measurements (6-8) at each of six different fixed flow rates. This means a total of approximately 36 to 48 individual measurements were taken.
• Data Provenance: The RBFV data was generated from bench testing using a "model eye simulation by fixed flow rates of human blood through a pipette of diameter 80 micron inner diameter."
  • This is an in-vitro, controlled environment simulation, not from human subjects.
  • The "human blood" component suggests a biological material, but it's used in a simulated, non-clinical setup.
  • There is no country of origin for the data in the context of human trials, as no human trials were performed for these specific RBFV measurements.
  • The data is prospective in the sense that it was generated specifically for this performance evaluation study.

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

Not applicable. The ground truth for the RBFV measurements was established by the calculated fluid dynamics of the human blood flowing through the pipette at fixed, controlled rates, which acted as the "actual" velocity. It was not based on expert interpretation.

4. Adjudication Method for the Test Set

Not applicable. The ground truth was based on calculated physical parameters, not expert consensus requiring an adjudication method.

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

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. The study focused solely on the standalone performance of the device's measurement capabilities in a bench setting. There is no mention of human readers or AI assistance in this context.

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

Yes, a standalone performance evaluation of the algorithm's measurement capabilities was performed. The bench testing directly assessed the RFI device's ability to measure RBFV against known, calculated values without human intervention in the measurement process (beyond operating the device).

7. Type of Ground Truth Used

The ground truth used for the RBFV performance studies was calculated velocity based on the fixed flow rates of human blood through a pipette, which served as a controlled and known reference. This is essentially a form of "physical/engineering ground truth" derived from a calibrated setup rather than clinical pathology or outcomes data.

8. Sample Size for the Training Set

The document does not specify any training set size. This submission is a Special 510(k) for a modification (change of fundus camera base) to an already cleared device, not an initial submission for a novel AI algorithm that would typically require a training set. The descriptions of the software "Grab and Browse module" suggest standard image acquisition and processing software rather than a machine learning model that undergoes training.

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

Not applicable, as no training set is mentioned or implied for the performance evaluation described.

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