Corneal astigmatism agreement between a swept-source ocular coherence tomography and Scheimpflug-Placido based...

This prospective and comparative study assesses the agreement of anterior, posterior, and total corneal astigmatism measurements between swept-source optical coherence tomography (Anterion) and Scheimpflug cameras, Placido disc, and OCT-based tomography (Galilei G6).

A total of 59 eyes of 59 patients were assessed using two optical biometers. Anterior, posterior, and total keratometry measurements were obtained, and flat (K1), steep (K2), astigmatic power, and J vectors (J₀ and J₄₅) were compared. Bland-Altman plots and intraclass correlation coefficients (ICC) were used to evaluate agreement and reliability between the devices.

Statistically significant differences were found for flat keratometry measurements of anterior corneal power (Galilei G6: 43.41 ± 1.78; Anterion: 43.32 ± 1.73) and total corneal power (Galilei G6: 42.41 ± 1.85; Anterion: 42.84 ± 1.81), as well as for steep keratometry of posterior corneal power (Galilei G6: - 6.41 ± 0.38; Anterion: - 6.31 ± 0.30) and total corneal power (Galilei G6: 43.69 ± 1.89; Anterion: 43.91 ± 1.89) (p < .05). In contrast, no statistically significant differences were found for the mean power vector components comparison between the devices. Agreement analysis showed significant proportional bias for cylindrical power and vector components (J₀ and J₄₅) of posterior and total astigmatism. No bias was observed with any of the anterior astigmatism and vector components. ICC showed showed relatively poor reliability (ICC < 0.5) between the device measurements moderate reliability for posterior corneal parameters.

Anterior, posterior, and total astigmatism measurements between the Anterion and Galilei G6 are not interchangeable.