Agreement between anterior segment swept source-OCT and Scheimpflug imaging corneal aberration measurements in healthy eyes

Abstract

To assess agreement between corneal aberration measurements made through swept-source optical coherence tomography using a new anterior segment imaging device (Anterion) and a Scheimpflug imaging device (Pentacam HR) in healthy subjects. Cross-sectional study. In 50 eyes of 50 healthy subjects, 14 aberration parameters (7 across the anterior corneal surface and 7 across the total surface) were measured in 4 mm and 6 mm optic zones using each device: oblique trefoil (Z3_-3), vertical coma (Z3_-1), horizontal coma (Z3_1), horizontal trefoil (Z3_3), spherical aberration (Z4_0), root mean square (RMS) lower order aberrations (LOA) and RMS higher order aberrations (HOA). Data for the two devices were compared through intraclass correlation coefficients (ICC), paired t tests, limits of agreement (LoA) and Bland Altman plots. Vertical coma was the only corneal aberration parameter that consistently showed excellent agreement (ICC > 0.8, mean difference -0.019, LoA -0.165 to 0.126). Good agreement (ICC = 0.75) between the devices was observed for RMS HOA, but this was slightly worse in the 6 mm optical zone (ICC = 0.667 for anterior RMS HOA). No over- or underestimation trend by one or other device was noted. Agreement was poor to moderate for the rest of the corneal parameters (ICC 0.2 to 0.7). Despite good agreement overall for vertical coma and RMS HOA values, agreement for the remaining corneal aberration measurements was poor to moderate. As mean differences in our sample were overall small, in normal eyes these devices could be clinically judged as interchangeable.