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

Completed

• Conditions: Corneal Topography

• Registration Number: NCT01861925
• Lead Sponsor: Haag-Streit AG

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2013-05-21
• Study First Submitted QC: 2013-05-23
• Study First Posted: 2013-05-24
• Study Start: 2013-06
• Primary Completion: 2013-07
• Study Completion: 2013-07
• Results First Submitted: 2014-03-03
• Status Verified: 2014-05
• Results First Submitted QC: 2014-05-13
• Last Update Submitted: 2014-05-13
• Results First Posted: 2014-06-05
• Last Update Posted: 2014-06-05

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 50

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
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	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).

Secondary Outcome Measures

Name	Time	Method
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.	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.

Trial Locations

Locations (1)

University Hospital Inselspital; 🇨🇭 Berne, Switzerland