Lenstar LS 900 Topography
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Corneal Topography
- Sponsor
- Haag-Streit AG
- Enrollment
- 50
- Locations
- 1
- Primary Endpoint
- 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
- Status
- Completed
- Last Updated
- 11 years ago
Overview
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.
Investigators
Eligibility Criteria
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
Outcomes
Primary Outcomes
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).
Secondary Outcomes
- 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)