(179 days)
The Cirrus™ HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases is indicated for in-vivo viewing, axial cross-sectional, and threedimensional imaging and measurement of anterior and posterior ocular structures.
The Cirrus™ HD-OCT is a non-contact, high resolution tomographic and biomicroscopic imaging device. It is indicated for in-vivo viewing, axial crosssectional, and three-dimensional imaging and measurement of anterior and posterior ocular structures, including cornea, retinal nerve fiber layer, macula, and optic disc. The Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL) and Macular Normative Database is a quantitative tool for the comparison of retinal nerve fiber layer 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™ HD-OCT is a computerized instrument that acquires and analyzes crosssectional tomograms of anterior and posterior ocular structures (including cornea, retina, retinal nerve fiber layer, macula, and optic disc). It emplovs non-invasive, non-contact, low-coherence interferometry to obtain these high-resolution images. Using this non-invasive optical technique. Cirrus HD-OCT produces high-resolution cross-sectional tomograms of the eye without contacting the eye.
Here's a breakdown of the acceptance criteria and study details for the Cirrus HD-OCT device, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The device's performance was evaluated across several key areas: Retinal Nerve Fiber Layer (RNFL) repeatability and reproducibility, retinal segmentation accuracy, retinal segmentation precision, agreement of retinal thickness measurements with a predicate device (Stratus OCT), and central corneal thickness measurements (CCT) repeatability, reproducibility, and agreement with ultrasound pachymetry.
Table 1: Acceptance Criteria and Reported Device Performance
| Feature/Metric | Acceptance Criteria (Stated or Implied) | Reported Device Performance |
|---|---|---|
| RNFL Repeatability and Reproducibility | Not explicitly stated as acceptance criteria, but demonstrating low variability. | Repeatability SD (average): 1.33 µm (overall average RNFL thickness) Reproducibility SD (average): 1.35 µm (overall average RNFL thickness) Repeatability Limit (average): 3.72 µm Reproducibility Limit (average): 3.78 µm (All within expected clinical precision, similar to independent study results: 1.3 µm in normals, 1.2 µm in patients) |
| RNFL Agreement with Stratus OCT | High Pearson correlation coefficient, acknowledging non-interchangeability. | Pearson correlation coefficient for average RNFL thickness: 0.953 (good correlation). Note: Cirrus measured thicker than Stratus for thinner RNFL, and thinner for thicker RNFL. Measurements from the two systems should not be used interchangeably. |
| Retinal Segmentation Accuracy (RPE Layer) | Software and hand-segmentations agreed for 100% of A-scans within specified tolerances. | 200x200 Scans: - AMD: 85.7% (60/70) - Diabetic Retinopathy: 95.2% (40/42) - VRI Disorder: 96.4% (27/28) - Other Retinal Disease: 86.3% (44/51) - Macular Edema: 96.4% (27/28) - No Retinal Disease: 100.0% (37/37) 512x128 Scans: - AMD: 86.1% (62/72) - Diabetic Retinopathy: 97.6% (41/42) - VRI Disorder: 89.3% (25/28) - Other Retinal Disease: 88.5% (46/52) - Macular Edema: 93.1% (27/29) - No Retinal Disease: 100.0% (40/40) |
| Retinal Segmentation Accuracy (ILM Layer) | Software and hand-segmentations agreed for 100% of A-scans within specified tolerances. | 200x200 Scans: - AMD: 97.1% (68/70) - Diabetic Retinopathy: 95.2% (40/42) - VRI Disorder: 92.9% (26/28) - Other Retinal Disease: 98.0% (50/51) - Macular Edema: 100.0% (28/28) - No Retinal Disease: 100.0% (37/37) 512x128 Scans: - AMD: 98.6% (73/74) - Diabetic Retinopathy: 95.2% (40/42) - VRI Disorder: 96.3% (26/27) - Other Retinal Disease: 98.1% (51/52) - Macular Edema: 96.6% (28/29) - No Retinal Disease: 100.0% (40/40) |
| Retinal Segmentation Precision (CSMT Repeatability) | Low standard deviation for central subfield macular thickness measurements. | Repeatability SD (µm) with Cirrus 4.0 MTA with Fovea Placement: - AMD: 6.3 - DR: 9.8 - VRI Disorder: 5.4 - Other: 7.5 - ME: 7.9 - No Disease: 2.2 Significantly improved with Fovea Placement and Registration compared to Cirrus 3.0 MTA alone. |
| Agreement of Retinal Thickness with Stratus OCT | Demonstrate and explain the mean difference, acknowledge non-interchangeability. | Mean Difference Cirrus – Stratus (µm) for Central Subfield: - AMD: 53.6 (SD: 35.0) - Diabetic Retinopathy: 40.0 (SD: 47.1) - VRI Disorder: 43.8 (SD: 35.9) - Other: 41.7 (SD: 47.1) - Macular Edema: 45.5 (SD: 45.3) - Normal: 59.4 (SD: 11.7) Non-interchangeable; better for qualitative comparison. |
| CCT Repeatability and Reproducibility | Not explicitly stated as acceptance criteria, but demonstrating low variability. | Repeatability SD: 4.08 µm Repeatability Limits: 11.42 µm Reproducibility SD: 4.23 µm Reproducibility Limits: 11.84 µm |
| CCT Agreement with Ultrasound Pachymetry | Demonstrate and explain the mean difference and consistency with other OCT devices. | Mean difference (Cirrus CCT - Ultrasound pachymetry CCT): -9.06 µm (SD: 5.63). Consistent with other OCT devices (e.g., Visante OCT is ~15.1 µm thinner than ultrasound). |
Study Details
The provided document describes several clinical evaluations rather than a single overarching study. Here's a breakdown for each:
1. RNFL Repeatability and Reproducibility Study
- Sample Size (Test Set): 32 normal subjects.
- Data Provenance: In-house study, likely US (not explicitly stated, but common for domestic manufacturers). Retrospective/Prospective not specified, but the nature of the study (inter-visit, inter-instrument) points to prospective data collection for this specific evaluation.
- Number of Experts & Qualifications: Not applicable or specified, as this focuses on objective measurement variability.
- Adjudication Method: Not applicable.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Yes (algorithm/device performance in measurement).
- Type of Ground Truth: N/A for repeatability/reproducibility; focuses on consistency of device measurements.
- Training Set Sample Size: N/A (this study evaluates the device's measurement consistency, not an AI model).
- Training Set Ground Truth: N/A.
2. RNFL Agreement with Stratus OCT Study
- Sample Size (Test Set): 130 subjects (normal and patients).
- Data Provenance: Not explicitly stated, but the reference to "a recent study" and the nature of the publication suggests a clinical research setting, likely academic and possibly multi-site. The reference mentions "Poster 4628, ARVO 2008," indicating an academic presentation.
- Number of Experts & Qualifications: Not applicable for establishing ground truth as it's a comparison of device measurements.
- Adjudication Method: Not applicable.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Yes (comparing two devices' standalone measurements).
- Type of Ground Truth: N/A; comparing measurements from two different OCT systems.
- Training Set Sample Size: N/A.
- Training Set Ground Truth: N/A.
3. Retinal Segmentation Accuracy and Precision Study
- Sample Size (Test Set): Both eyes of 370 subjects. One eye chosen as the "study eye." Subjects classified into 6 pathology groups (AMD, DR, VRI, Other Retinal, Macular Edema, No Retinal Pathology).
- Data Provenance: Four sites, location not specified (likely US, given the sponsor). Retrospective/Prospective not explicitly stated, but the controlled scanning protocol suggests prospective data collection for this evaluation.
- Number of Experts & Qualifications: Not explicitly stated, but "hand-segmentations" imply expert manual delineation. No specific qualifications are listed.
- Adjudication Method: Not explicitly stated, but since agreement was defined as software and hand-segmentations being within a certain micron range, there was a defined metric for evaluating agreement.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Yes (algorithm's ability to segment layers).
- Type of Ground Truth: "Hand-segmentations" by experts. This serves as the reference standard for evaluating the automatic segmentation algorithm's accuracy.
- Training Set Sample Size: N/A (this study evaluates the segmentation algorithm, not AI training specific to this device).
- Training Set Ground Truth: N/A.
4. Retinal Thickness Measurements: Agreement with Stratus Study
- Sample Size (Test Set): N=63 (AMD), N=39 (Diabetic Retinopathy), N=45 (VRI Disorder), N=53 (Other), N=35 (Macular Edema), N=48 (Normal) - total not explicitly summed but likely combined from the larger 370 subject cohort, or a subset.
- Data Provenance: Implied same as the Retinal Segmentation study (four sites, likely US, prospective-like data collection).
- Number of Experts & Qualifications: Not applicable for establishing ground truth, as it's a comparison of device measurements.
- Adjudication Method: Not applicable.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Yes (comparing two devices' standalone measurements).
- Type of Ground Truth: N/A; comparing measurements from two different OCT systems.
- Training Set Sample Size: N/A.
- Training Set Ground Truth: N/A.
5. Central Corneal Thickness (CCT) Measurements Study
- Sample Size (Test Set): Phase I: 28 subjects; Phase II: 22 subjects (different subjects). For CCT vs. Ultrasound: 50 eyes.
- Data Provenance: In-house study (likely US). Prospective data collection for both phases.
- Number of Experts & Qualifications: Not applicable for establishing ground truth for CCT measurements.
- Adjudication Method: Not applicable.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Yes (device measurement performance).
- Type of Ground Truth: N/A for repeatability/reproducibility. For CCT vs. Ultrasound, ultrasound pachymetry serves as a comparative reference, but not explicitly stated as "ground truth" for CCT itself in the same vein as expert pathology.
- Training Set Sample Size: N/A.
- Training Set Ground Truth: N/A.
6. RNFL and Macula Normative Databases
- Sample Size (Test Set): RNFL: 284 subjects (aged 19-84); Macula: 282 subjects (aged 19-84).
- Data Provenance: Seven sites, location not specified (likely multi-center within the US or potentially international, but typical for normative data collection). Prospective.
- Number of Experts & Qualifications: Not explicitly stated, but the subjects would have been confirmed "normal" by qualified clinicians, typically ophthalmologists or optometrists.
- Adjudication Method: N/A for normative database collection directly.
- MRMC Comparative Effectiveness Study: No.
- Standalone Performance: Not applicable, as this is the collection and analysis of normative data, not an algorithm's performance against it.
- Type of Ground Truth: Clinically determined healthy/normal status of subjects.
- Training Set Sample Size: N/A, this is the data from which normative ranges are derived or "trained" for comparison.
- Training Set Ground Truth: "Known normal subjects" based on clinical assessment.
Summary of AI Specifics:
The provided document describes the performance of an optical coherence tomography (OCT) device and its inherent algorithms for retinal layer segmentation and thickness measurement. It does not explicitly mention the use of "AI" in the modern sense of machine learning or deep learning models, nor does it present an "AI vs. no AI assistance" comparative effectiveness study for human readers. The algorithms described are more in line with traditional image processing and segmentation techniques. Therefore, questions related to AI effect size, AI training set specifics, and AI ground truth are not directly answered by this 2009 submission.
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510(K) SUMMARY
510(k) SUMMARY (per 21 CFR §807.92)
MAY - 5 2009
Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases
GENERAL INFORMATION
| Manufacturer: | Carl Zeiss Meditec, Inc.5160 Hacienda DriveDublin, California 94568(925) 557-4616 (phone)(925) 557-4259 (fax)Est. Reg. No. 2918630 |
|---|---|
| Contact Person: | Judith A. Brimacombe, MADirector, Regulatory/Clinical AffairsCarl Zeiss Meditec Inc.5160 Hacienda DriveDublin, California 94568(925) 557-4616 (phone)(925) 557-4259 (fax) |
| Classification name: | Tomography, Optical Coherence; Ophthalmoscope |
| Classification: | Class II (acc. 21 CFR 886.1570) |
| Product Code: | OBO |
| Trade/Proprietary name: | Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL)and Macular Normative Databases |
| PREDICATE DEVICES | |
| Company:Device: | Carl Zeiss Meditec, Inc.Cirrus™ HD-OCT (K063378) |
| Company:Device: | Carl Zeiss Meditec, Inc.StratusOCT™ with Retinal Nerve Fiber Layer (RNFL) &Macula Normative Database (K033123) |
| Company:Device: | Carl Zeiss Meditec, Inc.Visante OCT (K051789) |
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INTENDED USE
The Cirrus™ HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases is indicated for in-vivo viewing, axial cross-sectional, and threedimensional imaging and measurement of anterior and posterior ocular structures.
INDICATIONS FOR USE
The Cirrus™ HD-OCT is a non-contact, high resolution tomographic and biomicroscopic imaging device. It is indicated for in-vivo viewing, axial crosssectional, and three-dimensional imaging and measurement of anterior and posterior ocular structures, including cornea, retinal nerve fiber layer, macula, and optic disc. The Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL) and Macular Normative Database is a quantitative tool for the comparison of retinal nerve fiber layer 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.
DEVICE DESCRIPTION
The Cirrus™ HD-OCT is a computerized instrument that acquires and analyzes crosssectional tomograms of anterior and posterior ocular structures (including cornea, retina, retinal nerve fiber layer, macula, and optic disc). It emplovs non-invasive, non-contact, low-coherence interferometry to obtain these high-resolution images. Using this non-invasive optical technique. Cirrus HD-OCT produces high-resolution cross-sectional tomograms of the eye without contacting the eye.
SUBSTANTIAL EQUIVALENCE
It is the opinion of Carl Zeiss Meditec, Incorporated that the Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases is substantially equivalent to the Cirrus HD-OCT, Stratus OCT with RNFL and Macula Normative Databases and to the Visante OCT. The indications for use for the Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases is similar to the indications for the predicate devices cited in this application. A technological comparison and clinical testing demonstrate that the Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL) and Macular Normative Database is functionally equivalent to the predicate devices.
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Evaluation performed on the Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases supports the expanded indications for use statement and demonstrates that the device is substantially equivalent to the predicate devices and does not raise new questions regarding safety and effectiveness.
CLINICAL EVALUATION
Clinical data was collected and evaluated to support the indications for use statement for the Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases and to demonstrate substantial equivalence to the Cirrus HD-OCT, the Stratus OCT with RNFL and Macula Normative Databases as well as to the Visante OCT. Three of these studies are summarized below.
RNFL Repeatability and Reproducibility
An in-house study was performed on 32 normal subjects to determine the inter-visit and inter-instrument repeatability of Cirrus RNFL thickness measurements. The repeatability and reproducibility (including effects of multiple visits and multiple instruments), along with mean thickness, are shown in the table below. Similar results were also found in an independent study, with a repeatability standard deviation of 1.3 um in normal subjects and 1.2 um in patient eves'.
Table 1. Mean thickness. Repeatability and Reproducibility of Cirrus RNFL measurements for five sectors, including the overall average thickness, four quadrants (temporal, superior, nasal, and inferior), measured on 32 normal subjects.
| MeanThickness(μm) | RepeatabilitySD(μm) | ReproducibilitySD(μm) | RepeatabilityLimita(μm) | ReproducibilityLimitb(μm) | |
|---|---|---|---|---|---|
| Average | 93.0 | 1.33 μm | 1.35 μm | 3.72 μm | 3.78 μm |
| Temporal | 64.6 | 2.03 μm | 2.05 μm | 5.68 μm | 5.74 μm |
| Superior | 118.8 | 3.42 μm | 3.45 μm | 9.58 μm | 9.66 μm |
| Nasal | 68.6 | 2.19 μm | 2.24 μm | 6.13 μm | 6.27 μm |
| Inferior | 123.6 | 3.01 μm | 3.14 μm | 8.43 μm | 8.79 μm |
a. Repeatability Limit is the upper 95% limit for the difference between repeated results. Per ISO 5725-1 and ISO 5725-6, Repeatability Limit = 2.8 x Repeatability SD.
b. Reproducibility Limit is the upper 95% limit calculated for the difference between results repeated with different operators on different instruments. Each subject was imaged by a single operator twice during a single visit on five instruments (Phase 1) or three times each during three visits on a single instrument (Phase 2). Per ISO 5725-1 and ISO 5725-6, Reproducibility limit = 2.8 x Reproducibility SD.
4 Vizzeri, G, Weinreb, RN, Gonzalez-Garcia, AO, Bowd, C, Medeiros, F, Sample, PA, Zangwill, LM: Agreement between spectral-domain and time-domain OCT for measuring RNFL thickness, Br J Ophthalmol, March 2009.
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RNFL Agreement with Stratus OCT
A recent study of normal subjects and patients (N = 130) found that although there were differences between Stratus and Cirrus, the Pearson correlation coefficient for the average RNFL thickness was 0.953, indicating good correlation. However, they also found differences between Cirrus and Stratus RNFL measurements. Cirrus measured thicker than Stratus for thinner RNFL values, and measured thinner than Stratus for thicker (more normal) RNFL values. Measurements from the two systems should not be used interchangeably.
Retinal Segmentation Accuracy
A study was conducted at four sites to evaluate the accuracy and precision of the Cirrus HD-OCT retinal thickness segmentation algorithms and to evaluate the agreement between the resulting measurements and similar measurements made on Stratus OCT.
Both eyes of 370 subjects were scanned, with one eye being chosen as the study eye based on eligibility guidelines. Subjects were classified into the six groups based on the primary diagnosis causing the most pathologic abnormalities in the study eve as follows:
Group 1 - age-related macular degeneration (AMD),
Group 2 - diabetic retinopathy (DR).
Group 3 - vitreoretinal interface abnormalities (including macular holes),
Group 4 - other retinal pathology.
Group 5 - macular edema for which treatment was planned,
Group 6 - no retinal pathology.
Any subjects with a primary diagnosis that placed them within Groups 1 through 4. for whom treatment of macular edema was scheduled, were categorized into Group 5.
Two 200 x 200 scans and two 512 x 128 scans of the study and fellow eyes were acquired using the Cirrus SD-OCT instrument during a single visit. Retinal thickness in every subfield was calculated (based on the ETDRS 6 mm grid centered on the fovea).
The Cirrus inner limited membrane (ILM) and retinal pigment epithclium (RPE) segmentations were deemed accurate if software-segmentations and handsegmentations agreed for 100% of the A-scans that were evaluated, where agreement was defined as being within 16 um for the central 1mm of the scan and within 32 um
2 O.J. Knight, R.T. Chang, W.J. Feuer, D.L. Budenz, "Comparison of Retinal Nerve Fiber Laver Measurements Using Stratus OCT and Cirrus Spectral Domain OCT," Poster 4628, ARVO 2008
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elsewhere in the scan. The accuracy of segmentation was found to depend on layer (RPE or ILM) and disease category, and is summarized below in Tables 2 and 3.
| Category | 200x200 | 512x218 | ||
|---|---|---|---|---|
| n/N (%) | 95% CI | n/N (%) | 95% CI | |
| AMD | 60/70(85.7%) | (77.5%, 91.3%) | 62/72(86.1%) | (78.1%, 98.5%) |
| DiabeticRetinopathy | 40/42(95.2%) | (86.6%, 98.4%) | 41/42(97.6%) | (90.0%, 99.5%) |
| VRI Disorder | 27/28(96.4%) | (85.5%, 99.2%) | 25/28(89.3%) | (76.0%, 95.5%) |
| Other RetinalDisease | 44/51(86.3%) | (76.5%, 92.4%) | 46/52(88.5%) | (79.2%, 93.9%) |
| Macular Edema | 27/28(96.4%) | (85.5%, 99.2%) | 27/29(93.1%) | (82.2%, 97.7%) |
| No RetinalDisease | 37/37(100.0%) | (93.2%, 100%) | 40/40(100.0%) | (93.7%, 100%) |
Table 2. Accuracy of segmentations for RPE layer by pathology category
| Table 3. Accuracy of segmentations for II M layer by pathology category | ||||
|---|---|---|---|---|
| Category | 200x200 | 512x218 | ||
| n/N (%) | 95% CI | n/N (%) | 95% CI | |
| AMD | 68/70(97.1%) | (91.7%, 99.1%) | 73/74(98.6%) | (94.2%, 99.7%) |
| DiabeticRetinopathy | 40/42(95.2%) | (86.6%, 98.4%) | 40/42(95.2%) | (86.6%, 98.4%) |
| VRI Disorder | 26/28(92.9%) | (80.6%, 97.6%) | 26/27(96.3%) | (85.0%, 99.2%) |
| Other RetinalDisease | 50/51(98.0%) | (91.7%, 99.6%) | 51/52(98.1%) | (91.8%, 99.6%) |
| Macular Edema | 28/28(100.0%) | (91.2%, 100%) | 28/29(96.6%) | (85.9%, 99.2%) |
| No RetinalDisease | 37/37(100.0%) | (93.2%, 100%) | 40/40(100.0%) | (93.7%, 100%) |
Retinal Segmentation Precision
The repeatability of Cirrus HD-OCT retinal thickness measurements varied with pathology. Table 4 shows the repeatability standard deviation for each disease category for the central subfield average thickness. Repeatability can be improved by
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ensuring that two scans are registered to each other, as when the Macular Change Analysis is used. Repeatability can also be improved using the Macular Thickness Analysis when the fovea is correctly identified and used as the reference point for subfield average thickness calculations. These repeatability improvements are also shown in Table 4.
Table 4. Repeatability Standard Deviation" in micrometers for central subfield macular thickness (CSMT) measurements on the 200x200 scan using Macular Thickness Analysis (MTA), MTA with the ability to adjust the fovea position, and Macular Change Analysis (MCA), which uses registration and fovea placement. The total number of subjects for each disease category, and their means and standard deviations (SD) are also shown for reference.
| Category | N | Mean ± SDCSMT (µm)for Cirrus 4.0MTA | Central Subfield Macular ThicknessRepeatabilityStandard Deviation (µm) | ||
|---|---|---|---|---|---|
| Cirrus 3.0MTA | Cirrus 4.0MTA withFoveaPlacement | Cirrus 4.0MCA withRegistrationand FoveaPlacement | |||
| AMD | 77 | $255 \pm 65$ | 17.5 | 6.3 | 8.7 |
| DR | 51 | $335 \pm 109$ | 16.8 | 9.8 | 8.1 |
| VRI Disorder | 44 | $360 \pm 128$ | 14.4 | 5.4 | 4.3 |
| Other | 62 | $303 \pm 114$ | 10.1 | 7.5 | 4.5 |
| ME | 41 | $339 \pm 141$ | 13.5 | 7.9 | 7.0 |
| No Disease | 44 | $256 \pm 21$ | 4.8 | 2.2 | 2.5 |
a. Repeatability Limit is the upper 95% limit for the difference between repeated results. For this study, two scans were acquired per subject during a single visit on a single system by a single operator at one of four sites. Per ISO 5725-1 and ISO 5725-6, Repeatability limit = 2.8 x Repeatability SD.
Retinal Thickness Measurements: Agreement with Stratus
The segmentation algorithms in Cirrus HD-OCT and Stratus OCT are designed to search for different layers. Specifically, Stratus OCT locates the top of the bright reflective layer that is now known to represent the junction between inner and outer segments of the photoreceptors as the lower boundary of the retinal for its thickness calculations; Cirrus locates the brightest layer in the retinal pigment epithelium (RPE)/outer segment complex, which is thought to correspond to the RPE.
Because of this difference in segmentation strategy, there is a mean difference in the retinal thickness found by each instrument. Because the integrity of the layers sought varies with pathology, the mean difference between instruments varies with pathology, as can be seen in Table 5. Even after the mean difference has been accounted for, there is a residual difference that can be seen in the standard deviation of the difference reported in the last column of Table 5. Because of the residual
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difference, for an individual patient, it is better to compare scans between Stratus and Cirrus qualitatively, looking for changes in retinal morphology, rather than making decisions based on quantitative evaluation.
Table 5. Difference between Cirrus HD-OCT and Stratus OCT for the Central Subfield Mean Thickness for each of six categories of pathology
| Category | N | Mean (SD) Difference Cirrus – Stratus (µm) | Cirrus | Stratus | Difference |
|---|---|---|---|---|---|
| AMD | 63 | 271.3 (60.6) | 217.7 (54.2) | 53.6 (35.0) | |
| DiabeticRetinopathy | 39 | 356.6 (118.7) | 316.6 (135.8) | 40.0 (47.1) | |
| VRI Disorder | 45 | 386.3 (128.0) | 342.5 (125.0) | 43.8 (35.9) | |
| Other | 53 | 310.6 (99.5) | 268.9 (101.6) | 41.7 (47.1) | |
| Macular Edema | 35 | 351.1 (140.3) | 305.7 (127.9) | 45.5 (45.3) | |
| Normal | 48 | 256.1 (18.6) | 196.7 (18.6) | 59.4 (11.7) |
RNFL and Macula Normative Databases
The Cirrus RNFL and Macula normative databases were developed utilizing 284 subjects (aged 19-84) and 282 subjects (aged 19-84): respectively, collected from seven sites. The normative databases have a similar gender distribution (134 males. 150 females and 133 males, 149 females; respectively). Ethnicity breakdown of the Cirrus RNFL and Macula normative databases is as follows: 43% Caucasians, 24% Asians, 18% African American, 12% Hispanic, 1% Indian, and 6% mixed ethnicity. Note that Cirrus RNFL and Macula normative databases are adjusted only by age, not by axial length, refraction, optic disc area, signal strength or any other parameter.
Results revealed that the mean difference in the average thickness between any two race groups is within 6 um Caucasians have thinner mean average thickness, superior quadrant average, and inferior quadrant average. Asians seem to have thinner mean nasal quadrant average and thicker temporal quadrant average. The largest difference in the RNFL thickness between two race groups is for the temporal quadrant average between Asian and African American, with a difference of 16 um. The normative limits do not take into account differences that may be present due to ethnicity.
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Central Corneal Thickness Measurements
A study was conducted to determine repeatability and reproducibility of the Cirrus HD-OCT instrument measurements of central comeal thickness (CCT). Phase I of the study enrolled 28 subjects and was designed to determine inter-device variability. wherein each subject was imaged 3 times during a single visit on each of three Cirrus OCT instruments by one operator. Phase II enrolled 22 subjects and was designed to determine inter-operator variability, wherein cach subject was imaged three times during a single visit by each of three operators. Phases I and II enrolled different subjects.
The Cirrus HD-OCT repeatability and reproducibility are shown in Table 6. Mean thickness of each phase and overall (Phase I and II combined) are also shown. Since the random error variability from Phase II of the study was larger than that from Phase I, the variance components from Phase II were used to estimate the random measurement variability and the repeatability standard deviation.
| Table 6. Repeatability and reproducibility of central corneal thickness measurements | ||
|---|---|---|
| -- | -- | -------------------------------------------------------------------------------------- |
| Cirrus HD-OCTRepeatabilitya | Cirrus HD-OCTReproducibilityb | Mean Thickness | ||||
|---|---|---|---|---|---|---|
| SD(μm) | Limits(μm) | SD(μm) | Limits(μm) | Phase I(μm) | Phase II(μm) | Overall(μm) |
| 4.08 | 11.42 | 4.23 | 11.84 | 544.25 | 532.25 | 538.25 |
a. Repeatability Limit is the upper 95% limit for the difference between repeated results. Per ISO 5725-1 and ISO 5725-6, Repeatability Limit = 2.8 x Repeatability SD.
b. Reproducibility Limit is the upper 95 % limit calculated for the difference between results repeated using different operators. Lach subject was imaged three times during a single visit by each of three operators. Per ISO 5725-1 and ISO 5725-6, Reproducibility Limit = 2.8 x Reproducibility SD.
Difference in Central Corneal Thickness Measurement between Cirrus HD-OCT and Ultrasound Pachymetry
A study was conducted to determine the difference in central corneal thickness measurement between Cirrus HD-OCT and ultrasound pachymctry. A total of 50 eyes were enrolled at one site and measured by a single operator for each device. The results of this study, provided in Table 7, show that the mean difference in central corneal thickness measurements between Cirrus HD-OCT and ultrasound pachymetry is -9.06. The negative difference indicates that the Cirrus CCT measurement is thinner than the ultrasound CCT measurement. OCT devices in gencral measure thinner than ultrasound pachymetry. The Visante OCT user
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manual reports that Visante OCT measurements are thinner, on average, by 15.1 microns as compared to ultrasound pachymetry.
Table 7. Difference in Central Corneal Thickness Measurement between Cirrus HD-OCT and Ultrasound Pachymetry
| MeanDifference | SD | 95% CI of theDifference | ||
|---|---|---|---|---|
| Lower | Upper | |||
| Cirrus CCT-Ultrasoundpachymetry CCT(μm) | -9.06 | 5.63 | -10.66 | -7.46 |
SUMMARY
As described in this 510(k) Summary, all testing deemed necessary was conducted on the Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases to ensure that the device is safe and effective for its intended use when used in accordance with its Instructions for Use.
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DEPARTMENT OF HEALTH & HUMAN SERVICES
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MAY - 5 2009
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Public Health Service
Carl Zeiss Meditec, Inc. c/o Judith A. Brimacombe Director, Clinical & Regulatory Affairs Carl Zeiss Meditec, Inc. 5160 Hacienda Blvd. Dublin, CA 94568
Re: K083291
Trade/Device Name: Cirrus HD-OCT with Retinal Nerve Fiber Layer and Macular Normative Databases, Model 4000
Regulation Number: 21 CFR 886.1570 Regulation Name: Ophthalmoscope Regulatory Class: II Product Code: OBO Dated: April 15, 2009 Received: April 16, 2009
Dear Ms. Brimacombe:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Center for Devices and Radiological Health's (CDRH's) Office of Compliance at (240) 276-0115. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please contact the CDRH/Office of Surveillance and Biometrics/Division of Postmarket Surveillance at 240-276-3464. For more information regarding the reporting of adverse events, please go to http://www.fda.gov/cdrh/mdr/.
You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.
Sincerely yours,
Malvina B. Egleston, mD.
Malvina B. Eydelman, M.D. Director Division of Ophthalmic and Ear, Nose and Throat Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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INDICATIONS FOR USE STATEMENT
INDICATIONS FOR USE STATEMENT
510(k) Number (if known): K083291
Device Name: Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL) and Macular Normative Databases
Indications for Use:
The Cirrus™ HD-OCT is a non-contact, high resolution tomographic and biomicroscopic imaging device. It is indicated for in-vivo viewing, axial cross-sectional, and threedimensional imaging and measurement of anterior and posterior ocular structures, including cornea, retinal nerve fiber layer, macula, and optic disc. The Cirrus HD-OCT with Retinal Nerve Fiber Layer (RNFL) and Macular Normative Databases is a quantitative tool for the comparison of retinal nerve fiber layer 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, agerelated macular degeneration, and glaucoma.
Prescription Use x (Part 21 CFR 801 Subpart D)
AND/OR
Over-The-Counter Use (21 CFR 801 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
Daryl L. Kaufman
(Division Sign-Off) Division of Ophthalmic and Ear, Nose and Throat Devices
510(k) Number K083291
§ 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.