(218 days)
The PRIMUS instrument is a non-contact, high resolution tomographic imaging device. It is indicated for in-vivo viewing of axial cross sections and measurement of posterior ocular structures, including retinal nerve fiber layer, macula, and optic disc. It is intended for use as a diagnostic device to aid in the detection and management of ocular diseases including, but not limited to, macular edema, diabetic retinopathy, age-related macular degeneration and glaucoma.
The PRIMUS device is an ophthalmic instrument that provides the essential performance and functionality compared to the Carl Zeiss Meditec CIRRUS™ HD-OCT Model 4000 (K11157), with a separate manually-controlled patient interface and simplified analysis features. PRIMUS uses the same SD-OCT technology from the CIRRUS and offers a simplified user interface. In addition, the camera in the PRIMUS instrument operates at a reduced speed to acquire OCT images at comparable resolution in approximately the same amount of time.
The PRIMUS device is a computerized ophthalmologic instrument that acquires and allows visualization of cross-sectional tomograms of the eye using spectral domain optical coherence tomography (SD-OCT). The instrument is designed to scan the eye in a non-contact manner to acquire detailed cross-sectional images of various posterior ocular structures such as the retina and the optic nerve head. Various retinal structures of the eye from the internal limiting membrane to the retinal pigment epithelium (including layers such as the ganglion and retinal nerve fiber) can be imaged.
The PRIMUS instrument is available in one model, Model 200, which has a manually controlled patient interface and separate enclosure with components used in OCT scanning. The operator utilizes a keyboard, monitor and mouse to interface with the computer. Data acquired can be saved to the computer; PDFs of the reports may be saved to a USB-connected storage device.
The principle of operation is identical in that both devices employ a non-invasive, non-contact low-coherence interferometry technique [spectral domain optical coherence tomography (SD-OCT) to generate high-resolution cross-sectional images of internal ocular tissue microstructures by measuring optical reflections from tissue. Both provide cross sectional images of the posterior structures of the eye (i.e., retina, including the ganglion and retinal nerve fiber layers).
The device consists of two main parts: a manually controlled separate patient interface and an imaging engine box. The system is composed of a number of electrical, mechanical, and optical subsystems that are required to facilitate measurements and aid in patient alignment:
- Optical head modules
- SD-OCT engine modules
- Patient module
- Support modules
As part of its report driven workflow, at the completion of scan acquisition, PRIMUS presents the pre-ordered report(s) to the user in a sequential manner. The visualization and analysis reports that available in PRIMUS are as follows:
- Macular Thickness Analysis (MTA) Based on 512 X 32 Macular Cube Scan
- Optic Nerve Head (ONH) & Retinal Nerve Fiber Layer (RNFL) Analysis Based on 128 X 128 ONH & RNFL Cube Scan
- HD 5-line Analysis Based on 5 line HD Raster Scan
- HD 1-line Analysis Based on 1 line HD Raster Scan
The provided text describes a 510(k) summary for the PRIMUS 200 ophthalmic instrument, focusing on demonstrating its substantial equivalence to a predicate device (Cirrus HD-OCT Model 4000). The information pertains to the device's technical characteristics and performance in clinical evaluation, but it doesn't describe the acceptance criteria and performance against those criteria in a typical AI/ML medical device submission format.
However, based on the provided text, I can infer the "acceptance criteria" are implicitly demonstrating that the performance of the PRIMUS 200 is comparable to the predicate device, with mean differences and limits of agreement falling within acceptable clinical ranges, and showing good repeatability and reproducibility. The study essentially aims to prove that the PRIMUS 200 performs as well as the predicate for the specified measurements.
Here's a breakdown of the requested information based on the provided document:
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A table of acceptance criteria and the reported device performance
The document does not explicitly state acceptance criteria in a formal, quantifiable way as you might find for an AI/ML device (e.g., "accuracy > X%" or "sensitivity > Y%"). Instead, the "acceptance criteria" are implied by demonstrating substantial equivalence to the predicate device. This is primarily assessed by comparing the mean differences and limits of agreement between the two devices for various ocular measurements. Good repeatability and reproducibility are also considered.
Since no specific numerical acceptance thresholds are given, the reported device performance is presented as the findings from the comparative effectiveness study:
Implied Acceptance Criteria & Reported Device Performance for PRIMUS 200 vs. CIRRUS 4000
Metric Implied Acceptance Criterion (relative to predicate) Reported Device Performance (Mean Differences, PRIMUS 200 - CIRRUS 4000) Comparative Analysis Mean differences and 95% Limits of Agreement should demonstrate substantial equivalence (i.e., differences are clinically acceptable and comparable to predicate). Normal Eyes (N=45):
- Macular Thickness: Mean differences range from -4.8 µm (Outer Inferior) to +0.1 µm (Central Subfield).
- RNFL Thickness: Mean differences range from -2.8 µm (Inferior) to -1.2 µm (Temporal).
- ONH Parameters: Mean differences range from -0.02 mm² (Rim Area, Disc Area) to +0.01 (Average Cup-to-Disc Ratio, Vertical Cup-to-Disc Ratio).
Retinal Disease Eyes (N=39): - Macular Thickness: Mean differences range from -6.2 µm (Outer Inferior) to +1.8 µm (Central Subfield).
Glaucomatous Eyes (N=43): - RNFL Thickness: Mean differences range from -3.0 µm (Nasal) to +1.2 µm (Temporal).
- ONH Parameters: Mean differences range from 0.00 (Rim Area, Average Cup-to-Disc Ratio, Vertical Cup-to-Disc Ratio) to 0.02 mm² (Disc Area).
The studies conclude that the mean values of the 19 thickness parameters were very similar between the two devices, demonstrating substantial equivalence. |
| Repeatability and Reproducibility | Measurements should show good repeatability and reproducibility. | Normal Eyes (N=44): - Repeatability SDs: Macular thickness parameters (0.90% to 1.76% COV), RNFL thickness parameters (2.12% to 5.01% COV), ONH parameters (1.844% to 6.702% COV).
- Reproducibility SDs: Macular thickness parameters (1.67% to 2.26% COV), RNFL thickness parameters (2.76% to 5.72% COV), ONH parameters (2.397% to 7.660% COV).
Diseased Eyes (N=38 for Macular, N=43 for RNFL/ONH): - Repeatability SDs: Macular thickness parameters (1.14% to 4.02% COV), RNFL thickness parameters (3.02% to 6.10% COV), ONH parameters (1.829% to 8.645% COV).
- Reproducibility SDs: Macular thickness parameters (1.59% to 4.52% COV), RNFL thickness parameters (3.89% to 8.36% COV), ONH parameters (2.091% to 8.814% COV).
The studies conclude that PRIMUS 200 showed good repeatability and reproducibility for both normal and diseased eyes. |
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Sample sizes used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Comparative Analysis:
- Sample Size: 127 subjects (45 normal, 39 retinal disease, 43 glaucoma subjects).
- Data Provenance: The study was a "prospective study." The country of origin of the data is not specified in the provided text.
- Repeatability and Reproducibility Study:
- Sample Size: 125 subjects (44 normal, 38 retinal disease, 43 glaucoma subjects).
- Data Provenance: Not explicitly stated as retrospective or prospective for this specific study, but it follows the comparative analysis which was prospective. Country of origin not specified.
- Comparative Analysis:
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This is not an AI/ML device where expert-labeled ground truth for images is typically established. This is a medical device designed for making objective measurements (thickness, area, ratios). The "ground truth" for the comparative analysis is the measurements obtained from the predicate device (Cirrus HD-OCT Model 4000), which is a legally marketed device. The study aims to show that the PRIMUS 200 produces measurements comparable to this established predicate. Experts are involved in operating the devices and potentially interpreting the results, but they are not establishing a subjective "ground truth" for each case in the same way as an image interpretation task.
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Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable. This is not a study assessing diagnostic performance based on subjective interpretations or needing adjudication of disagreeing expert opinions. The study compares quantitative measurements obtained by two different devices.
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If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
No. This is not an AI/ML device that assists human readers. It is an imaging device that produces quantitative measurements. The study is a direct comparison of measurements between the proposed device and a predicate device.
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If a standalone (i.e. algorithm only without human-in-the loop performance) was done
Yes, in the sense that the device itself performs the measurements. The "algorithm" here is the device's inherent measurement capability. The clinical evaluation directly compares the measurements generated by the PRIMUS 200 (device only with human operation) to those generated by the predicate device (also device only with human operation). It's a device-to-device comparison for quantitative outputs.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" is established by the measurements from the predicate device, the Carl Zeiss Meditec CIRRUS™ HD-OCT Model 4000 (K111157), which is an already cleared device for similar indications. The study's purpose is to demonstrate that the PRIMUS 200 produces measurements that are substantially equivalent to this established device.
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The sample size for the training set
Not applicable. This device is not described as an AI/ML device that requires a training set in the conventional sense. Its functionality is based on established optical coherence tomography (OCT) technology and software for measurement rather than a machine learning model trained on a dataset.
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How the ground truth for the training set was established
Not applicable, as there is no mention of a machine learning training set or associated ground truth.
§ 886.1570 Ophthalmoscope.
(a)
Identification. An ophthalmoscope is an AC-powered or battery-powered device containing illumination and viewing optics intended to examine the media (cornea, aqueous, lens, and vitreous) and the retina of the eye.(b)
Classification. Class II (special controls). The device, when it is an AC-powered opthalmoscope, a battery-powered opthalmoscope, or a hand-held ophthalmoscope replacement battery, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 886.9.