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GlaucomaNCT07350304

Comparison of Two OCT Device RNFL and GCIPL Measurements in Mild, Moderate, and Severe Glaucoma

An observational study of Glaucoma, run by Twin Cities Eye Consultants at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This research study was designed to evaluate how consistently two different imaging devices measure the thickness of retinal layers in patients with glaucoma. The two machines, the Topcon Maestro2 and the Zeiss Cirrus 5000, are commonly used in eye clinics to take high-resolution scans of the retina and optic nerve. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Glaucoma
What is being tested?
Optical Coherence Tomography
How many people
141 participants
Where
1 siteUnited States
Study dates
28 Oct 2024to 14 Feb 2025
How long will I take part?
1 Day
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: The study population consisted of adult patients aged 18 years or older with established or suspected glaucoma. Subjects were consecutively enrolled from a single tertiary ophthalmology practice in Minnesota. The final cohort included a range of glaucoma severity (mild, moderate, and severe) and was predominantly composed of White (59.6%) and female (59.6%) individuals. All participants underwent same-day, back-to-back OCT imaging on both the Topcon Maestro2 and Zeiss Cirrus 5000 systems.

Who may be able to join

  • Male or female patients at least 18 years of age
  • A diagnosis of mild, moderate or severe glaucoma.
  • Optic nerve appearance characteristic of glaucoma.
  • < +/- 6D Spherical equivalent Refractive Error
  • BCVA ≥ 20/40
  • Previous Zeiss OCT RNFL with signal strength of ≥ 7/10
  • The subject is able to understand the requirements of the study and provide written informed consent.
  • Subject is willing to follow study instructions, agrees to comply with all study procedures and testing.

Who cannot join

  • If pseudophakic, PCO must be ≤ trace
  • If phakic, the cataract must be ≤ 1+
  • No diagnosis of optic nerve disease other than glaucoma, and no macular disease.
  • Current participation or participation in any drug or device clinical trial (which includes the fellow eye) within the past 30 calendar days.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Twin Cities Eye Consultants

    Coon Rapids, Minnesota, 55433

Other trials in United States

About this study

This research study was designed to evaluate how consistently two different imaging devices measure the thickness of retinal layers in patients with glaucoma. The two machines, the Topcon Maestro2 and the Zeiss Cirrus 5000, are commonly used in eye clinics to take high-resolution scans of the retina and optic nerve. These scans help doctors monitor glaucoma and detect disease progression.

The goal of this study was to compare the results from both machines when scanning the same patients, and to determine how closely their measurements align. Researchers also developed mathematical models that allow doctors to convert results from one machine to the other, which could help ensure consistency when a patient receives scans on different devices over time or at different clinics.

Read more

A total of 141 eyes from patients with varying levels of glaucoma severity were included in the study. Scans were performed using standard imaging protocols on both machines. Researchers analyzed the average thickness of two important retinal layers: the retinal nerve fiber layer (RNFL) and the ganglion cell-inner plexiform layer (GCIPL).

This study helps improve our understanding of how different imaging devices compare and provides tools for standardizing results across platforms. The findings may help eye care providers make more confident decisions when reviewing images from different machines, improving the care and monitoring of patients with glaucoma.

This was an investigator-initiated study sponsored by Twin Cities Eye Consultants with funding support from Topcon Healthcare. No new medications, treatments, or procedures were tested as part of this research. The study only involved non-invasive eye imaging scans that are already widely used in clinical practice.

Read the detailed description

This investigator-initiated, cross-sectional study was designed to assess the level of agreement between optical coherence tomography (OCT) measurements captured by two commercially available imaging platforms: the Topcon Maestro2 and the Zeiss Cirrus 5000. These devices are widely used in the clinical management of glaucoma to quantify structural biomarkers such as retinal nerve fiber layer (RNFL) thickness and ganglion cell-inner plexiform layer (GCIPL) thickness.

The motivation behind this study stems from real-world variability in imaging hardware across clinical settings. Patients may undergo imaging on different machines due to equipment availability, clinic referral patterns, or evolving device infrastructure. As each device uses proprietary software algorithms and scan acquisition protocols, there can be small but clinically significant differences in reported measurements-even when scanning the same eye under similar conditions. Understanding this variability is critical for ensuring continuity of care and accuracy in longitudinal monitoring of glaucoma.

The study enrolled 141 eyes from patients with established glaucoma, screened from a single clinical practice. The first 72 eyes enrolled were designated as the derivation cohort, while the subsequent 69 eyes comprised the validation cohort. Each subject underwent back-to-back imaging on both devices during the same session using manufacturer-recommended scan protocols: the Topcon Wide Scan, RNFL Cube, and Macular Cube protocols; and the Zeiss Optic Disc Cube 200×200 and Macular Cube 512×128 protocols. All imaging was performed by a single, trained technician using factory-default acquisition settings and standard dilation (phenylephrine 2.5% and tropicamide 1%), with eye-tracking (FastTrac) enabled where available.

Average RNFL thickness and GCIPL thickness were extracted from each scan and compared between devices. Measurements were further analyzed by quadrant (RNFL) and sector (GCIPL) to evaluate regional agreement. Generalized linear models and Deming regression were used to evaluate the level of agreement and construct conversion equations between devices. Results were evaluated based on clinical thresholds of ±3 microns-a commonly accepted tolerance for scan-to-scan variability on a single device.

Repeatability of Topcon scans was also assessed using three consecutive scans on the same visit. Intra-device variability was analyzed using mean differences and 95% limits of agreement to determine reliability across protocols. Exploratory subgroup analyses were performed by glaucoma severity, gender, race/ethnicity, and visual acuity to explore potential drivers of scan variability or poor agreement.

The study found that while mean RNFL and GCIPL measurements from the two devices were highly correlated, statistically significant differences in average values were observed. This reinforces the importance of accounting for device-specific variability in both research and clinical practice. Derived conversion equations demonstrated strong performance in the validation cohort, particularly for global RNFL and GCIPL metrics. Sector-level agreement was more variable, particularly in the temporal RNFL and superotemporal GCIPL sectors, indicating that clinicians should use caution when interpreting regional values across platforms.

Importantly, scan repeatability on the Maestro2 was excellent, particularly for macular GCIPL metrics, highlighting its reliability for longitudinal monitoring. This supports the growing role of widefield and integrated OCT imaging in clinical glaucoma care.

The study was approved by Sterling IRB and conducted at Twin Cities Eye Consultants (Minnesota). It involved no investigational treatments or interventions beyond standard OCT imaging. Funding support was provided by Topcon Healthcare, which had no role in study design, data analysis, or manuscript preparation. Results from this study are intended to inform clinicians, researchers, and device manufacturers regarding the interoperability and clinical translation of OCT imaging biomarkers in glaucoma.

Conditions
Glaucoma
Being tested
Optical Coherence Tomography
Keywords
Glaucoma, OCT, Optical Coherence Tomography
Medical subject headings
Glaucoma

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Optical Coherence TomographyDiagnostic test

    Also called OCT, Maestro2, Cirrus 5000

    Subjects underwent bilateral Optical Coherence Tomography (OCT) imaging using both the Topcon Maestro2 and Zeiss Cirrus 5000 devices during the same clinical session. Manufacturer-recommended protocols were used: Wide Scan, RNFL Cube, and Macular Cube (Topcon), and Optic Disc Cube 200×200 and Macular Cube 512×128 (Zeiss). Imaging was performed back-to-back using factory-default settings and standardized pupil dilation to assess cross-platform agreement and repeatability of RNFL and GCIPL thickness measurements in glaucomatous eyes.

Study groups in NCT07350304
Study groupRoleWhat they receive
DerivationThe derivation cohort consisted of the first 72 eyes enrolled in the study. These participants had established glaucoma and were selected consecutively from a single clinical practice. Each eye underwent back-to-back OCT imaging using both the Topcon Maestro2 and Zeiss Cirrus 5000 devices during the same visit. Data from this cohort were used to develop statistical conversion models assessing agreement and potential equivalence in RNFL and GCIPL thickness measurements across platforms. Non-interventional imaging procedures were performed using standard manufacturer-recommended scan protocols. These included the Topcon Wide Scan, RNFL Cube, and Macular Cube protocols, as well as the Zeiss Optic Disc Cube 200×200 and Macular Cube 512×128 protocols. All scans were conducted by a single trained technician under controlled clinical conditions.
Receives: Diagnostic Test: Optical Coherence Tomography
ValidationThe validation cohort included the subsequent 69 eyes enrolled in the study, following the derivation cohort. Imaging procedures and clinical characteristics mirrored those of the derivation group. This cohort was used to test and validate the accuracy and reliability of the conversion models derived from the initial group. Subjects underwent the same non-invasive imaging protocols on both the Topcon Maestro2 and Zeiss Cirrus 5000 devices during a single clinic session. Scan protocols, technician, and environmental conditions were consistent with those of the derivation cohort to preserve standardization.
Receives: Diagnostic Test: Optical Coherence Tomography

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Agreement Between Topcon Maestro2 and Zeiss Cirrus 5000 OCT Devices

    This primary outcome evaluates the cross-platform agreement of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness measurements between the Topcon Maestro2 and Zeiss Cirrus 5000 devices in glaucoma and glaucoma-suspect eyes. The analysis will assess absolute differences, standard deviation, 95% limits of agreement, and proportion of eyes within a ±3 micron threshold for global and sectoral measurements.

    Measured: Day of single study visit

Secondary outcomes (4)
  1. Repeatability of Topcon Maestro2 OCT Measurements

    Evaluate the test-retest repeatability of RNFL and GCIPL thickness measurements acquired with the Topcon Maestro2 Wide, RNFL Cube, and Macular Cube scan protocols. Repeatability will be assessed using standard deviation of repeated measures, coefficient of variation (CV), and intraclass correlation coefficients (ICC) when applicable.

    Measured: Day of single study visit

  2. Impact of Glaucoma Severity on Device Agreement

    Assess whether glaucoma severity (mild, moderate, or severe) influences agreement between RNFL and GCIPL thickness values measured by the Topcon Maestro2 and Zeiss Cirrus 5000. Stratified analyses will be conducted for both derivation and validation cohorts.

    Measured: Day of single study visit

  3. Cross-Device Agreement by Quadrant and Sectoral Analysis

    Evaluate device agreement on a quadrant-by-quadrant and sectoral basis for both RNFL and GCIPL layers. The analysis will include superior, inferior, nasal, and temporal quadrants for RNFL, and superotemporal, superonasal, inferotemporal, and inferonasal sectors for GCIPL.

    Measured: Day of single study visit

  4. Predictive Modeling to Convert Measurements Between Devices

    Develop linear regression models using the derivation cohort to predict Zeiss Cirrus RNFL and GCIPL values based on Topcon Maestro2 outputs. Validate model performance in a separate validation cohort within ±3 microns.

    Measured: Day of single study visit

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted20 Jan 2026
  2. Study start28 Oct 2024
  3. Primary completion14 Feb 2025
  4. Study completion14 Feb 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Case only
Time perspective
Prospective
Enrolment
141 participants (actual)
Target duration
1 Day
IDs, dates and publications
ClinicalTrials.gov ID
NCT07350304
Sponsor's protocol ID
TCEC-001
Status last verified
Dec 2025
First submitted
29 Dec 2025
Last updated
20 Jan 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
Yes
Individual data sharing
No

Publications

  • Tan O, Chopra V, Lu AT, Schuman JS, Ishikawa H, Wollstein G, Varma R, Huang D. Detection of macular ganglion cell loss in glaucoma by Fourier-domain optical coherence tomography. Ophthalmology. 2009 Dec;116(12):2305-14.e1-2. doi: 10.1016/j.ophtha.2009.05.025. Epub 2009 Sep 10.

    PubMed 19744726
  • Wong E, Yoshioka N, Kalloniatis M, Zangerl B. Cirrus HD-OCT short-term repeatability of clinical retinal nerve fiber layer measurements. Optom Vis Sci. 2015 Jan;92(1):83-8. doi: 10.1097/OPX.0000000000000452.

    PubMed 25479451
  • Kotowski J, Wollstein G, Folio LS, Ishikawa H, Schuman JS. Clinical use of OCT in assessing glaucoma progression. Ophthalmic Surg Lasers Imaging. 2011 Jul;42 Suppl(0):S6-S14. doi: 10.3928/15428877-20110627-01.

    PubMed 21790113
  • Vazirani J, Kaushik S, Pandav SS, Gupta P. Reproducibility of retinal nerve fiber layer measurements across the glaucoma spectrum using optical coherence tomography. Indian J Ophthalmol. 2015 Apr;63(4):300-5. doi: 10.4103/0301-4738.158064.

    PubMed 26044467
  • Mwanza JC, Oakley JD, Budenz DL, Anderson DR; Cirrus Optical Coherence Tomography Normative Database Study Group. Ability of cirrus HD-OCT optic nerve head parameters to discriminate normal from glaucomatous eyes. Ophthalmology. 2011 Feb;118(2):241-8.e1. doi: 10.1016/j.ophtha.2010.06.036. Epub 2010 Oct 28.

    PubMed 20920824

Questions about this trial

What is this clinical trial studying?

An observational study of Glaucoma, run by Twin Cities Eye Consultants at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 8 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 20 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Agreement Between Topcon Maestro2 and Zeiss Cirrus 5000 OCT Devices (time frame: Day of single study visit). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07350304, which also lists 5 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jan 2026.

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