Agreement between Scheimpflug-Placido topographer (Sirius) and anterior-segment swept-source optical coherence tomography (ANTERİON) devices for corneal high order aberrations in keratoconic and healthy eyes.

Purpose: To compare the Scheimpflug-Placido Topographer (SP-T; Sirius) and anterior-segment Swept-Source Optical Coherence Tomography (asSS-OCT; ANTERİON) for high order corneal aberrations in healthy subjects and patients diagnosed with stage 1 and 2 keratoconus.

Methods: The 125 eyes of 125 patients were included in the study and were divided into four groups based on their stage of keratoconus (KC) and the presence or absence of corneal cross-linking (CXL). The first group (KC1 group, n = 33) consisted of patients with stage 1 KC who underwent CXL, while the second group (ncKC1 group, n = 33) comprised patients with stage 1 KC who did not receive CXL. The third group (KC2 group, n = 26) included patients with stage 2 KC who underwent CXL, and the final group (control group, n = 33) consisted of healthy subjects. Root mean square (RMS) HOA (High-order aberration), horizontal trefoil (TrA), spherical aberration (SpA) and horizontal coma were compared between the SP-T and asSS-OCT to determine differences and agreement.

Results: A notable difference was observed between the devices in the control group for RMS HOA, horizontal TrA, and coma (p = 0.001, p = 0.026 and p < 0.001, respectively). In the KC1 group, a proportional bias was identified with regard to horizontal coma and RMS HOA (p = 0.025 and p = 0.043). For SpA, a proportional and fixed bias was observed in both the ncKC1 and control groups.

Conclusions: In the KC2 group, all parameters were in agreement, proving interchangeability between the SP-T and asSS-OCT devices. However, horizontal coma and HOA in KC1, as well as SpA in the control and ncKC1 groups, did not demonstrate this agreement. The interchangeability between devices may change according to the KC stage or CXL status.