Scheimpflug-Placido topographer and optical low-coherence reflectometry biometer: repeatability and agreement

Area of Science:

• Ophthalmology
• Biomedical Optics
• Corneal Imaging Technology

Background:

• Accurate ocular measurements are crucial for diagnosing and managing various eye conditions.
• Comparing different diagnostic devices ensures consistency and reliability in clinical practice.

Purpose of the Study:

• To evaluate the repeatability of measurements obtained from the Sirius Scheimpflug-Placido topographer and the Lenstar LS900 optical low-coherence reflectometry (OLCR) biometer.
• To determine the limits of agreement (LoA) between these two devices for key ocular parameters.

Main Methods:

• A comparative evaluation was conducted on 40 healthy eyes.
• Measurements for central corneal thickness (CCT), anterior chamber depth (ACD), mean keratometry (K), and white-to-white (WTW) corneal diameter were repeated three times on each device.
• Repeatability was assessed using within-subject standard deviation, and agreement was analyzed using the Bland-Altman LoA method.

Main Results:

• Both the Sirius topographer and Lenstar biometer demonstrated excellent repeatability for all assessed parameters.
• Repeatability coefficients for CCT were 3.10 μm and 3.32 μm, for WTW diameter 0.04 mm and 0.05 mm, and for mean K 0.17 D and 0.10 D, respectively.
• ACD measurements showed high repeatability (0.02 mm) for both devices, and Bland-Altman analysis confirmed all parameters were within clinically acceptable limits.

Conclusions:

• The Sirius Scheimpflug-Placido topographer and Lenstar LS900 biometer exhibit excellent repeatability for CCT, ACD, mean K, and WTW diameter.
• The good limits of agreement between the two devices suggest they are interchangeable for these specific ocular measurements.