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Tonometry for Measuring and Recording Intraocular Pressures and Intraocular Pressure Pulse Amplitudes, Pulsatile Ocular Blood Flow, Pulsatile Ocular Blood Volume, Pulsatility Index Equivalent (PEQ).

The Paradigm Medical Industries, Inc. Blood Flow Analyzer (BFA) is an electronic pneumatic tonometer capable of measuring and recording the intraocular pressure. The pressure measurements are made at a rate of 200 times per second over a period of 5-15 seconds. Contact with the eye is by means of a sterilized single-use per patient probe having an integral membrane that isolates the cornea from the internal pneumatic operation of the BFA. The pulsatile ocular blood flow is derived from the intraocular pressure measurements acquired with the pneumatic tonometer using mathematical equations that link intraocular pressure to ocular volume change and volume flow.

The Blood Flow Analyzer (BFA) is an electronic pneumatic tonometer that measures and records intraocular pressure at a high frequency. It then derives pulsatile ocular blood flow from these measurements using mathematical equations. The device also calculates pulsatile ocular blood volume, pulse amplitude, and a pulsatility index equivalent (PEQ).

Here's an analysis of the provided information regarding acceptance criteria and the supporting study:

1. Table of Acceptance Criteria and Reported Device Performance

The provided document, a 510(k) summary, details the device's capabilities and mentions studies related to its reproducibility and reliability. However, it does not explicitly state specific quantitative acceptance criteria for its performance metrics (Intraocular Pressure, Pulse Amplitudes, Pulsatile Ocular Blood Flow, Pulsatile Ocular Blood Volume, or Pulsatility Index Equivalent).

Instead, the document highlights claims of reproducibility and reliability for key measurements. The study primarily focused on establishing normative data for pulsatile ocular blood flow, rather than directly demonstrating performance against pre-defined acceptance thresholds for device accuracy or precision for a 510(k) submission.

Therefore, we can only infer the performance from the descriptions given:

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

• Test Set Description: The document describes a "Study Protocol for Normative Pulsatile Ocular Blood Flow." This study serves as the primary data used to support the device's characterization, particularly for the pulsatile ocular blood flow measurement.
• Sample Size: The overall sample size for the "Normative Pulsatile Ocular Blood Flow" study was 1502. Out of these, 777 subjects satisfied the inclusion criteria to be considered "normal."
• Data Provenance: The study was conducted at six optometric centers in the United Kingdom in 1995 and sponsored by OBF Labs (UK), Ltd. The data is retrospective in the context of this 510(k) submission, as it was collected in 1995 and presented in 2002.

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

The document states that the "normative data set was analyzed at Moorfields Eye Hospital, London," a renowned ophthalmic institution. However, it does not specify the exact number of experts involved in establishing the ground truth (i.e., defining "normal" or analyzing the data for the normative values). It also does not detail their specific qualifications (e.g., "radiologist with 10 years of experience").

The "normal" definition relied on a patient questionnaire with five negative answers, indicating:

• No family history of glaucoma.
• No significant ocular history (ocular diseases, treatments, or surgery).
• No use of ocular medications.
• No significant medical history (systemic hypertension, diabetes, or vascular disease).
• No use of systemic beta blockers.

This definition of "normal" serves as the ground truth for the normative data set.

4. Adjudication Method for the Test Set

The document does not describe an adjudication method (e.g., 2+1, 3+1) for the test set. The determination of "normal" was based on a direct patient questionnaire. The analysis of the normative data set was performed at Moorfields Eye Hospital, suggesting expert review, but no multi-reader adjudication process is detailed.

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

A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed or described in the provided 510(k) summary. The document does not discuss human reader performance with or without AI assistance, as the device's function is automated measurement rather than an AI-assisted diagnostic read.

6. Standalone (Algorithm Only) Performance Study

The entire description of the device's function and the normative study effectively describes standalone performance. The "Blood Flow Analyzer (BFA)" is an instrument that takes measurements and performs calculations automatically to output values like intraocular pressure, pulsatile ocular blood flow, etc. The studies mentioned (reproducibility and reliability, normative data collection) are all assessments of the device's performance in this standalone capacity.

7. Type of Ground Truth Used

For the normative data study, the ground truth was established by expert-defined clinical criteria obtained through a patient questionnaire. This questionnaire defined what constituted a "normal" subject based on the absence of specific ocular or systemic conditions and medications. This is akin to using clinical state or healthy control definitions as the ground truth.

For the fundamental intraocular pressure measurements, the document mentions that "The pressure-volume relation was derived by analyzing the pressure responses to injections of volumes of fluid to living human eves measured by direct cannulation of the eye connected to a manometer." This implies an invasive, direct physiological measurement was used to establish the foundational relationship for the device's calculations.

8. Sample Size for the Training Set

The document does not explicitly describe a separate "training set" as would be common for machine learning algorithms. The device performs calculations based on established physiological principles and equations. The normative data collected from the 777 "normal" subjects and the reproducibility/reliability studies serve to characterize the device's performance and establish normal ranges, rather than train an AI model in the conventional sense.

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

Since there is no explicitly defined "training set" in the context of machine learning, this question is not directly applicable. However, the foundational "ground truth" for the device's core calculations (like the pressure-volume relation) was established via direct physiological measurements (direct cannulation of the eye connected to a manometer). For the "normative data," the ground truth for classification of "normal" was based on the patient questionnaire's clinical criteria.

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