Using an optical low-coherence reflectometry (OLCR) biometer and Scheimpflug-Placido topographer are both as effective for measuring corneal parameters, claims a study in the Journal of Cataract and Refractive Surgery.
Dr Wuhe Chen et al., Eye Hospital of Wenzhou Medical College, Wenzhou, China, evaluated 40 subjects. One randomly healthy eye of each participant was measured three times with both devices.
The parameters measured included central corneal thickness (CCT), anterior chamber depth (ACD) from the corneal epithelium and from the endothelium, mean keratometry (K) and white-to-white (WTW) corneal diameter.
Within-subject standard deviation was used to calculate the repeatability of the scans. Agreement between the two devices was evaluated using the Bland-Altman limits of agreement (LoA) method. A mean of three scans were performed in order to assess LoA.
Repeatability of the Scheimpflug-Placido topographer and OLCR biometer was 3.10 μm and 3.32 μm for CCT. For WTW corneal diameter was 0.04 mm and 0.05 mm and for mean K it was 0.17 D and 0.10 D for mean K for the the Scheimpflug-Placido topographer and OLCR biometer, respectively.
According to the Bland-Altman LoA analysis, all parameters were within clinically sufficient limits. Both devices presented good repeatability for all parameters and can be used interchangeably between parameters.