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Repeatability and agreement between a reference Scheimpflug tomographer and a low-cost Scheimpflug system
Wenjun Xu1, Changbin Zhai, Mayinuer Yusufu
1From the Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab, Beijing, China (Xu, Zhai, Gan, Li, Zheng, Kang); Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia (Yusufu); Department of Surgery (Ophthalmology), The University of Melbourne, Melbourne, Australia (Yusufu).
The Scansys corneal topographer demonstrates good repeatability for various ocular measurements in myopic eyes. However, it is only interchangeable with Pentacam for anterior corneal curvature measurements.
Area of Science:
- Ophthalmology
- Optometry
- Biomedical Engineering
Background:
- Corneal topography is crucial for diagnosing and managing refractive errors and ocular conditions.
- Scheimpflug imaging offers advanced corneal analysis.
- Comparing different devices ensures accurate and reliable clinical data.
Purpose of the Study:
- To evaluate the repeatability and agreement of Scansys and Pentacam Scheimpflug topographers.
- To assess their performance in measuring ocular parameters in myopic eyes.
Main Methods:
- A cross-sectional study involving 204 myopic subjects undergoing refractive surgery evaluation.
- Measurements included corneal curvature, astigmatism, thickness, volume, anterior chamber depth (ACD), anterior chamber volume (ACV), and pupil diameter.
- Repeatability assessed using intraclass correlation coefficient, Cronbach's alpha, coefficient of variation, and Bland-Altman plots.
Main Results:
- Scansys exhibited good repeatability for anterior/posterior corneal curvature (Kf, Ks, Km), astigmatism, central corneal thickness (CCT), corneal volume, ACD, and ACV.
- Bland-Altman analysis showed narrow limits of agreement for corneal curvature, CCT, corneal volume, and ACD between Scansys and Pentacam.
- No significant differences were found in anterior corneal Kf and Km between the two devices.
Conclusions:
- Scansys demonstrates high repeatability for key corneal and anterior segment parameters.
- Interchangeability between Scansys and Pentacam is limited to anterior corneal curvature measurements.
- These findings aid in selecting appropriate devices for clinical and research applications in myopic eyes.
