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The iCare ST500 tonometer is a device intended to be used for the intraocular pressure of the human eye.

The iCare ST500 tonometer is intended to be used by healthcare professionals.

The iCare ST500 tonometer is based on a patented, induction-based rebound method, which allows intraocular pressure (IOP) to be measured by a healthcare professional accurately, rapidly and without an anesthetic. The iCare ST500 tonometer measures a patient's IOP while he or she is in an upright (sitting) position. It is attached to a slit lamp with the ST500 Adapter, making it easy to use during a standard eye exam. This tonometer is designed only for use with a slit lamp not as a handheld device. The tonometer is compatible with most of the common slit lamp models on the market.

The tonometer system consists of the iCare ST500 tonometer (together with ST500 Remote and ST500 Adapter, ST500 SmartCradle and a medical power supply used with ST500 SmartCradle), and a compatible printer and slit lamp.

With the iCare rebound measurement method, a miniature, lightweight, single-use probe is launched in a direction perpendicular to the surface of the center of the cornea of the eye. The probe is composed of a medical grade plastic tip and a metal shaft. The metal shaft is magnetized prior to the measurement. During the measurement, the probe can be considered to act like a moving magnet that induces an electric signal in the surrounding coil allowing for a highly accurate measurement of the probe's motion. After launching. the probe briefly contacts the cornea and bounces back. The tonometer records multiple parameters covering the motion of the probe, including deceleration, and rebound time. Using a proprietary algorithm, the device can calculate the eye's IOP.

The displayed IOP reading is derived from the results from a sequence of six individual probe rebounds. The displayed IOP measurement is also stored in the tonometer's memory for later retrieval.

The iCare ST500 tonometer has a rechargeable battery and can be charged in the ST500 SmartCradle powered by a medical power supply. The tonometer can be operated by using the buttons on the tonometer or by using the wireless battery-operated ST500 Remote control.

Here's a breakdown of the acceptance criteria and study details for the iCare ST500 (TA04) tonometer, based on the provided FDA 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

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

• Clinical Test Set Sample Size: 156 eligible eyes from 165 enrolled subjects. In cases where both eyes were eligible, the eye with the higher GAT reference pressure was used for analysis.
• Data Provenance: Not explicitly stated from which country the data originated. It mentions "subjects having an appointment to the investigational site and from subjects recruited using a study announcement," implying a prospective study conducted at one or more clinical sites, likely in Finland where the applicant is based.

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

• The document implies that Goldmann Applanation Tonometer (GAT) measurements were used as the reference standard (ground truth) in the clinical study. It does not specify the number of expert ophthalmologists or optometrists who performed the GAT measurements, nor their detailed qualifications (e.g., years of experience). Healthcare professionals would typically perform GAT measurements.

4. Adjudication Method for the Test Set

• The document does not describe any specific adjudication method for the test set. Given that GAT is considered a clinical gold standard, it's possible that a single GAT measurement was taken as truth, or if multiple readings were taken, the average was used without formal adjudication by additional experts.

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

• No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done concerning AI assistance. This device is a tonometer with an AI-like algorithm for IOP calculation, but the focus of the clinical study was on its standalone accuracy against an established reference (GAT), not on human reader improvement with or without AI assistance. The "AI" here refers to the proprietary algorithm used to calculate IOP from probe motion, not a diagnostic AI system assisting human interpretation.

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

• Yes, a standalone performance study was done for the iCare ST500 tonometer. The clinical study compares the device's measurements directly to GAT, indicating its standalone performance without human interpretation or adjustment of the device's numerical output. The "algorithm only" aspect is embedded within the device's functionality to calculate IOP.

7. The Type of Ground Truth Used

• Clinical Ground Truth: Goldmann Applanation Tonometer (GAT) measurements. GAT is widely considered the clinical gold standard for intraocular pressure measurement.

8. The Sample Size for the Training Set

• The document does not provide information about a separate training set or its sample size. The device uses a "proprietary algorithm" to calculate IOP, but details on how this algorithm was developed, trained, or validated (if machine learning was used) are not disclosed in this summary. The provided clinical and bench testing data refer to the validation of the finalized device.

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

• As the document does not mention a specific training set, it does not provide details on how ground truth for such a set would have been established. If the proprietary algorithm involved machine learning, its training data and ground truth establishment would be a separate, undisclosed process. The current document focuses on the regulatory validation of the final product.

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