Study of Clinical Performance of Corneal Topography Measurement Using an Optical Biometer

May 13, 2014 updated by: Haag-Streit AG

Lenstar LS 900 Topography

The purpose of this study is to quantify in-vivo repeatability of a new corneal topography measurement mode of an optical biometer, and the clinical performance of measurement in comparison to reference devices.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Switzerland
      • Berne, Switzerland, 3010
        • University Hospital Inselspital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Volunteers recruited at University Hospital

Description

Inclusion Criteria:

  • 18 years or older

Exclusion Criteria:

  • No corneal transplants
  • No corneal scar(s)
  • No acute infections of the eye
  • No weak fixation
  • No suspected lack of compliance
  • No vulnerable population

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Normal eye
Astigmatism smaller than 1.5 diopters
Large regular astigmatism
Astigmatism of > 1.5 diopters, regular astigmatism.
Large irregular astigmatism
Astigmatism of > 1.5 diopters, irregular astigmatism.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
In-vivo Repeatability of Corneal Topography Measurements With Lenstar LS 900 Topography: Sample Mean of Differences of Mean Power and Sample Mean of Std. Dev of Local Power Differences Between Two Consecutive Measurements
Time Frame: 1 day of examination

Corneal topography is a measurement of the shape of the anterior cornea. The shape of a cornea can be fully quantified by providing a map of local power. "Diopter" is the unit of refractive power of a lens. In case of the cornea, the power K [diopter] is related to the radius (curvature) R [mm] of the best fitting sphere by the relation K=337.5/R.

Here, corneal topography measurements are implemented by the Placido method, i.e. by analyzing the reflection image of a ring-shaped illumination.

According to International Standards Organization (ISO) 19980-2012, repeatability of corneal topography is assessed on the central cornea: area with diameter d<=3mm, and middle cornea: 3mm<d<=6mm.

"power difference (2 rep. meas.)": sample mean and 95% C.I. of differences of spatial mean of corneal power between two consecutive measurements.

"power difference 2 std.dev.": sample mean of twice the deviation of local power differences (two consecutive measurements).
1 day of examination

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Equivalence of Corneal Topography Measurement Between Lenstar LS 900 Topography and Atlas 9000: Sample Mean of Differences of Mean Power and Sample Mean of Std. Dev of Local Power Differences for One Measurement Per Device.
Time Frame: 1 day of examination

For definition of corneal topography, corneal power in "diopter", areas of evaluation and methods, see outcome 1.

This outcome measure aims at testing the equivalence of corneal topography measurement between Lenstar LS 900 Topography (Haag Streit) and Atlas 9000 (Zeiss) by analyzing differences in measurement results for the same eye between both devices.

"power difference (2 devices)" is the sample mean and 95% C.I. of differences of spatial mean of corneal power between two devices. This value quantifies systematic differences between devices (e.g. calibration), ignoring local variations of the power measurement.

"power difference (2 std.dev.)" is the sample mean of twice the standard deviation of local power differences between measurements with both devices. This value quantifies the spatially resolved agreement of corneal shape measurement of the two devices.
1 day of examination

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Equivalence of Corneal Topography Measurement Between Lenstar LS 900 Topography and Atlas 9000: Sample Mean of Std. Dev. of Local Corneal Elevation Differences for One Measurement Per Device.
Time Frame: 1 day of examination

For definition of corneal topography, areas of evaluation and methods, see outcome 1 and 2.

Corneal elevation refers to the distance between the measured corneal surface and the best fitting sphere, and is given in µm.

This outcome measure aims at testing the equivalence of corneal topography measurement between Lenstar LS 900 Topography (Haag Streit) and Atlas 9000 (Zeiss) by analyzing differences in measurement results for the same eye between both devices.

"elevation difference (2 std. dev.)" is the sample mean of twice the standard deviation of local corneal elevation differences between measurements with both devices. This value quantifies the spatially resolved agreement of corneal shape measurement of the two devices.
1 day of examination
Equivalence of Keratometry Radius Measurement Between Lenstar LS 900 Topography and Lenstar LS 900: Population Mean of Differences of Keratometry Radius Measurement Between Both Devices.
Time Frame: 1 day of examination

Keratometry radius refers to the corneal curvature R (see primary measure outcome). In this context, the cornea is approximated by a toric surface which can be characterized by a flat meridian (radius R1) and a steep meridian (radius R2) with an angle of 90 degrees between these meridians.

This outcome measure aims at testing the equivalence of keratometry radius measurement between Lenstar LS 900 Topography and Lenstar LS 900 (both Haag Streit) by analyzing differences in measurement results for the same eye between both devices.

Reported are: population mean of difference and 95% confidence interval of mean difference for radius of flat meridian (R1) and radius of steep meridian (R2).
1 day of examination
Equivalence of Keratometry Axis Measurement Between Lenstar LS 900 Topography and Lenstar LS 900: Population Mean of Differences of Keratometry Axis Measurement Between Both Devices.
Time Frame: 1 day of examination

Keratometry axis refers to the axis of the flat meridian of the toric representation of the cornea. For additional information see outcome 4.

This outcome measure aims at testing the equivalence of keratometry axis measurement between Lenstar LS 900 Topography and Lenstar LS 900 (both Haag Streit) by analyzing differences in measurement results for the same eye between both devices.

Reported are: population mean of difference and 95% confidence interval of mean difference for axis of flat meridian.
1 day of examination

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Haag-Streit AG

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University Hospital Inselspital, Berne

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Beatrice Frueh, Prof. Fr., University Hospital Inselspital, Berne

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2013

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2013

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2013

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 21, 2013

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 23, 2013

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 24, 2013

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 5, 2014

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 13, 2014

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2014

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HS-LS900-TOPO-01

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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