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The CIRRUS photo is a non-contact, high resolution tomographic and biomicroscopic imaging device that incorporates a digital camera which is suitable for photographing, displaying and storing the data of the retina and surrounding parts of the eye to be examined under mydriatic and non-mydriatic conditions.

These photographs support the diagnosis and subsequent observation of eye diseases which can be visually monitored and photographically documented. The CIRRUS photo is indicated for in vivo viewing, axial cross sectional, and three-dimensional imaging and measurement of posterior ocular structures, including retinal nerve fiber layer, macula and optic disc as well as imaging of anterior ocular structures and measurement of central corneal thickness.

It also includes a Retinal Nerve Fiber Layer (RNFL), Optic Nerve Head (ONH), and Macular Normative Database which are quantitative tools for the comparison of retinal nerve fiber layer, optic nerve head, and the macula in the human retina to a database of known normal subjects. 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 holes, cystoid macular edema, diabetic retinopathy, age-related macular degeneration, and glaucoma.

The CIRRUS photo is a computerized optical instrument that combines the diagnostic and imaging capabilities of the Carl Zeiss Meditec VISUCAM PRO NM Digital Camera and the Carl Zeiss Meditec Cirrus HD-OCT Optical Coherence Tomographer Model 4000. The CIRRUS photo was developed to provide both subjective and objective imaging, and to optimize space by combining fundus photography and spectral domain optical coherence tomography, allowing the anterior or posterior segments of the eye to be viewed and photographically documented with the pupil in a non-mydriatic state, within the same instrument. To optimize the workflow, the system applies the same optical beam delivery system for imaging and scanning.

The CIRRUS photo consists of a Fundus Camera Main Unit and a spectral domain optical coherence tomographer (SD-OCT) Module, both of which are installed on a single instrument table. The CIRRUS photo is operated via computer mouse, keyboard and joystick as part of the base of the main unit and an external monitor is mounted on top of the instrument table.

The CIRRUS photo is offered in two models. Model 600 and Model 800. Fundus auto fluorescence is available on both the Model 600 and 800; the Model 800 also offers fluorescein angiography and indocyanine green angiography (ICGA).

CIRRUS photo data can be analyzed using the same Cirrus HD-OCT algorithms and normative database cleared under K111157 (Cirrus HD-OCT software version 6.0), including Advanced Retinal Pigment Epithelium (RPE) Analysis, Guided Progression Analysis (GPA) for Optic Nerve Head (ONH) parameters, and Ganglion Cell Analysis, and the Ganglion Cell Normative Database. As these algorithms and database reside separately on the Cirrus HD-OCT version 6.0 software, the analyses of the CIRRUS photo data are carried out using an external Cirrus Review station.

The CIRRUS photo Models 600 and 800 underwent several studies to demonstrate substantial equivalence to predicate devices and to support expanded indications for use. Key studies focused on evaluating the repeatability, reproducibility, and comparability of measurements between the CIRRUS photo and the Cirrus HD-OCT Model 4000 for Central Corneal Thickness (CCT), RPE illumination/elevation, and Ganglion Cell Analysis (GCA) parameters.

The primary method for establishing acceptance criteria and demonstrating performance was through equivalence studies, comparing the new device against a predicate device (Cirrus HD-OCT Model 4000) for key measurement parameters. The acceptance criteria generally involved demonstrating that the mean difference between measurements from the CIRRUS photo and the predicate device was close to zero, with narrow 95% Confidence Intervals and Limits of Agreement, and that repeatability and reproducibility standard deviations were small.

Here's a breakdown of the acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria (Implicit / Demonstrated Equivalence to Predicate, and good Repeatability/Reproducibility)

• Phase I: -0.89 µm (95% CI: -2.85, 1.06)
• Phase II: 1.20 µm (95% CI: 0.22, 2.19)
  Repeatability (SD): 4.49 µm (COV: 0.8%)
  Reproducibility (SD): 5.216 µm (COV: 0.96%)
  Performance meets implicit criteria for agreement and precision. |
  | Area of Sub-RPE Illumination (mm²) | Mean difference between devices close to 0; 95% CI of mean difference crossing 0 or very small; 95% Limits of Agreement clinically acceptable. Good repeatability and reproducibility (small SD and COV). | Mean Difference (CIRRUS photo - Cirrus HD-OCT):
• 200x200 Scan: -0.0108 mm² (95% CI: -0.1632, 0.1416)
• 512x128 Scan: -0.0314 mm² (95% CI: -0.1742, 0.1115)
  Repeatability (SD): 0.1099 mm² (200x200), 0.1329 mm² (512x128)
  Reproducibility (SD): 0.1774 mm² (200x200), 0.2442 mm² (512x128)
  Performance meets implicit criteria for agreement and precision. |
  | Closest Distance to Fovea (mm) | Mean difference between devices close to 0; 95% CI of mean difference crossing 0 or very small; 95% Limits of Agreement clinically acceptable. Good repeatability and reproducibility (small SD and COV). | Mean Difference (CIRRUS photo - Cirrus HD-OCT):
• 200x200 Scan: 0.01 mm (95% CI: -0.01, 0.02)
• 512x128 Scan: 0.02 mm (95% CI: -0.00, 0.03)
  Repeatability (SD): 0.0343 mm (200x200), 0.0397 mm (512x128)
  Reproducibility (SD): 0.0447 mm (200x200), 0.0571 mm (512x128)
  Performance meets implicit criteria for agreement and precision. |
  | Area of RPE Elevation (mm²) | Mean difference between devices close to 0; 95% CI of mean difference crossing 0 or very small; 95% Limits of Agreement clinically acceptable. Good repeatability and reproducibility (small SD and COV). | Mean Difference (CIRRUS photo - Cirrus HD-OCT, 3mm Circle):
• 200x200 Scan: -0.040 mm² (95% CI: -0.098, 0.018)
• 512x128 Scan: -0.004 mm² (95% CI: -0.074, 0.066)
  Reproducibility COV%: 8.30% (200x200, 3mm Circle), 8.89% (512x128, 3mm Circle)
  Performance meets implicit criteria for agreement and precision. |
  | Volume of RPE Elevation (mm³) | Mean difference between devices close to 0; 95% CI of mean difference crossing 0 or very small; 95% Limits of Agreement clinically acceptable. Good repeatability and reproducibility (small SD and COV). | Mean Difference (CIRRUS photo - Cirrus HD-OCT, 3mm Circle):
• 200x200 Scan: -0.0024 mm³ (95% CI: -0.0050, 0.0002)
• 512x128 Scan: 0.0002 mm³ (95% CI: -0.0029, 0.0034)
  Reproducibility COV%: 8.45% (200x200, 3mm Circle), 9.07% (512x128, 3mm Circle)
  Performance meets implicit criteria for agreement and precision. |
  | Ganglion Cell Analysis (GCA) Parameters (e.g., Average GCL+IPL Thickness) | Mean difference between devices close to 0; 95% CI of mean difference crossing 0 or very small; 95% Limits of Agreement clinically acceptable. Good repeatability and reproducibility (small SD and COV). | Mean Difference (CIRRUS photo - Cirrus HD-OCT, Average Thickness):
• Normal Eyes: -0.3 µm (95% CI: -0.5, -0.2)
• Diseased Eyes: -0.3 µm (95% CI: -0.5, -0.2)
  Reproducibility COV% (Average Thickness): 0.97% (Normal), 0.98% (Diseased)
  Performance meets implicit criteria for agreement and precision across numerous GCA parameters. |
  | GCA Normative Database Transference | CIRRUS photo measurements should be comparable to Cirrus HD-OCT to allow adjustment and use of the established normative database. | Regression analysis was used to adjust the Cirrus HD-OCT GCA Normative Database for use with CIRRUS photo, creating an "adjusted CIRRUS photo Normative Database." This indicates successful transference and adjustment. |

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

The studies were prospective. The country of origin is not explicitly stated, but the company is based in Germany with a US contact, suggesting a likely multi-site international or US-based study given the English language requirement in one study.

Test Set Sample Sizes:

• Central Corneal Thickness (CCT) Study:
  • Phase I (inter-device variability): 29 subjects enrolled, 28 included in analysis.
  • Phase II (inter-operator variability): 23 subjects enrolled and qualified for analysis.
• Area of Increased Illumination under RPE (dry AMD with GA) Study: 21 enrolled subjects, with at least one eye qualifying. Mean age 79.8 years.
• Elevated RPE (dry AMD with drusen) Study: 31 enrolled subjects, with at least one eye qualifying. Mean age 80.1 years.
• Ganglion Cell Analysis (GCA) Normal Eyes Study:
  • Phase I (inter-operator variability): 30 subjects.
  • Phase II (inter-device variability): 33 subjects. Combined mean age 43.5 years.
• Ganglion Cell Analysis (GCA) Diseased Eyes (Glaucoma) Study: 77 subjects enrolled, 68 included in analysis (37 mild, 16 moderate, 13 severe, 2 end-stage glaucoma). Mean age 67.4 years.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

The studies described are primarily comparability, repeatability, and reproducibility studies, not diagnostic accuracy studies against a definitive ground truth established by experts in the traditional sense. The "ground truth" here is the measurement obtained by the predicate device (Cirrus HD-OCT Model 4000) and the consistency of measurements within and between devices/operators.

For the RPE analyses (increased illumination and elevated RPE), operators reviewed and manually edited the automated segmentation algorithm output when necessary, consistent with instructions. This suggests that the operators (who were administering the tests) were also implicitly acting as "experts" for reviewing and refining the data derived by the algorithm, effectively enhancing the quality of the algorithmic output, but not establishing a separate, independent ground truth. The number and qualifications of these "operators" are not explicitly stated as "experts" in the clinical evaluation sense, but rather as trained personnel for device operation and data review.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

There was no explicit independent adjudication method (like 2+1 or 3+1) described for establishing ground truth from multiple experts. For the RPE studies, the "ground truth" was derived from the automated segmentation algorithms, with manual editing by the operating personnel, but without a formal multi-reader consensus process indicated. The focus was on comparing measurements between devices and assessing measurement consistency.

5. 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 MRMC comparative effectiveness study was conducted or described in the provided text. The studies focused on the performance of the device's measurement algorithms themselves (standalone performance and comparability to a predicate device), not on how human readers' diagnostic accuracy is improved with or without AI assistance from this specific device.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done**

Yes, standalone performance was implicitly evaluated through the comparability, repeatability, and reproducibility studies. The device measures various parameters (CCT, RPE illumination/elevation, GCA thickness values) using its inherent algorithms. The comparison against the predicate device (Cirrus HD-OCT Model 4000) essentially evaluates the standalone measurement capability of the CIRRUS photo's algorithms against an established standard. While human operators are involved in operating the device and in some cases, reviewing and correcting automated segmentations (especially for RPE analyses), the core "performance" being evaluated is the accuracy and precision of the numerical measurements generated by the device's algorithms.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

The "ground truth" in these studies was primarily comparative to a predicate device (Cirrus HD-OCT Model 4000) and statistical measures of repeatability and reproducibility. For the advanced RPE analysis, the ground truth for the segmentation of increased illumination areas and RPE elevations was the output of the device's automated segmentation algorithm, refined by manual editing from the operators. There is no mention of pathology, expert consensus (beyond operator review), or long-term outcomes data as a definitive ground truth for individual measurements.

8. The sample size for the training set

The training set information is only explicitly provided for the Ganglion Cell Normative Database, which was adapted for the CIRRUS photo.

• GCA Normative Database: Derived from an additional analysis of the Cirrus HD-OCT Macular Thickness normative database, which included 282 subjects. These subjects were aged 19-84 years, considered representative of a normal population, and data was collected from seven sites.

For the other advanced algorithms (e.g., Advanced RPE Analysis, GPA), the document states they "reside separately on the Cirrus HD-OCT version 6.0 software" and are carried out using an external Cirrus Review station. This implies these algorithms were developed and likely trained prior to this submission, on data associated with the predicate Cirrus HD-OCT system (K111157), but specific training set sizes for these individual algorithms are not provided within this document.

9. How the ground truth for the training set was established

For the Ganglion Cell Normative Database (and by extension the Macular Thickness normative database):

• The ground truth was established by identifying subjects deemed "representative of a normal population."
• Scans were acquired from these normal subjects.
• Segmentation algorithms were applied to identify the thickness of specific layers (e.g., combined ganglion cell plus inner plexiform layers for GCA).
• These measurements from normal subjects then formed the reference values for the normative database, which is age-corrected. This database essentially defines "normal" based on statistical distribution from this large sample.

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The CIRRUS photo (Models 600 and 800) is a non-contact, high resolution tomographic and biomicroscopic imaging device that incorporates a digital camera which is suitable for photographing, displaying and storing the data of the retina and surrounding parts of the eye to be examined under mydriatic and non-mydriatic conditions.

These photographs support the diagnosis and subsequent observation of eye diseases which can be visually monitored and photographically documented. The CIRRUS photo is indicated for in vivo viewing, axial cross sectional, and three-dimensional imaging and measurement of posterior ocular structures, including retina, retinal nerve fiber layer, macula, and optic disc as well as imaging of anterior ocular structures, including the cornea.

It also includes a Retinal Nerve Fiber Layer (RNFL), Optic Nerve Head (ONH), and Macular Normative Database which is a quantitative tool for the comparison of retinal nerve fiber layer, optic nerve head, and the macula in the human retina to a database of known normal subjects. 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 holes, cystoid macular edema, diabetic retinopathy, age-related macular degeneration, and glaucoma.

The CIRRUS photo is a non-contact, high resolution digital, tomographic and biomicroscopic imaging device that merges fundus imaging and optical coherence tomography into a single device. To optimize the workflow, the system applies the same beam delivery system for imaging and scanning.

Here's a detailed breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:

Device: CIRRUS photo Models 600 and 800 (Fundus Camera and Optical Coherence Tomography)

Acceptance Criteria and Reported Device Performance

The acceptance criteria for the CIRRUS photo are not explicitly listed as specific thresholds in the document (e.g., "accuracy > 90%"). Instead, the study aimed to demonstrate equivalence and repeatability/reproducibility of measurements between the CIRRUS photo and the predicate device (Carl Zeiss Meditec Cirrus HD-OCT Model 4000).

Therefore, the "acceptance criteria" are implicitly that the differences in measurements between the two devices should be small and within acceptable limits (as evidenced by confidence intervals and limits of agreement), and that the CIRRUS photo should demonstrate good repeatability and reproducibility.

The reported device performance section details the findings from these equivalence and repeatability studies.

Study Details

1. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

   • Normal Eyes Study:
     • Phase 1 (Inter-operator variability): 30 subjects
     • Phase 2 (Inter-device variability): 33 subjects
   • Diseased Eyes Study:
     • Retinal disease (inter-device): 19 subjects
     • Retinal disease (inter-operator): 19 subjects
     • Glaucoma (inter-device): 17 subjects
     • Glaucoma (inter-operator): 18 subjects
   • Total Test Set: 63 normal subjects, 73 diseased subjects (total of 136 subjects, though there's some overlap in eyes examined across phases/devices, but subjects did not participate in both phases of a study)
   • Data Provenance: The document does not specify the country of origin of the data. The studies were prospective.

2. 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)

   • The study design focused on comparing measurements from the new device (CIRRUS photo) to an existing, cleared device (Cirrus HD-OCT Model 4000), which itself presumably has established accuracy.
   • The "ground truth" here is the measurement obtained from the predicate device. Therefore, no external experts were used to establish a separate "ground truth" beyond the measurements themselves.
   • For the inter-operator variability phases, four operators were involved, implying expertise in operating OCT devices. However, their specific qualifications (e.g., years of experience, medical degree) are not detailed.

3. Adjudication method (e.g. 2+1, 3+1, none) for the test set

   • Not applicable. This was a quantitative measurement comparison study, not a diagnostic classification study requiring adjudication of expert opinions. The method involved calculating mean differences, confidence intervals, and limits of agreement between device measurements.

4. 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, a MRMC comparative effectiveness study was not done. This study focuses on the technical equivalence and repeatability/reproducibility of a diagnostic imaging device (OCT) rather than evaluating human reader performance with or without AI assistance.
   • The term "AI" is not mentioned in this document.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

   • Yes, the primary studies described are standalone performance evaluations of the device, focusing on the measurements generated by the CIRRUS photo itself compared to a predicate device. While human operators are involved in acquiring the images, the analysis of the measurement data (31 parameters of RNFL, ONH, and macular thickness) is performed by the device's algorithms. The document does not describe a human-in-the-loop study to modify or interpret the device's measurements.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

   • The "ground truth" in this context is the measurement data obtained from the predicate device (Cirrus HD-OCT Model 4000). The study aimed to show that the CIRRUS photo provides comparable measurements. It's a device-to-device comparison rather than an evaluation against a clinical ground truth like pathology or patient outcomes.

7. The sample size for the training set

   • The document implies that the CIRRUS photo uses a "normative database" (RNFL, ONH, and Macular Normative Database) which comes from the Cirrus HD-OCT Model 4000 and is adjusted based on regression analysis. However, it does not specify the sample size of this underlying normative database or detail a separate "training set" for the CIRRUS photo's algorithms in this context. The study described focuses on testing a new device's performance against an established device, not on training a new algorithm.

8. How the ground truth for the training set was established

   • As noted above, a distinct "training set" for the CIRRUS photo's algorithms (other than the inherited normative database from the predicate device, K083291; K111157) is not explicitly described. For the normal subjects in the "Normative Database," the implicit "ground truth" would be their classification as "normal" based on clinical criteria and measurements from the original predicate device (Cirrus HD-OCT 4000). The method for establishing this original normative database's "ground truth" is not explained in this document.

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