Influence of trifocal intraocular lenses on standard automated refraction and aberrometer-based automated refraction

Purpose: To study the agreement between manifest refraction (Rx) and objective refraction (ObjRx) measured with two autorefractor models and an aberrometer, in eyes implanted with a trifocal diffractive intraocular lens. Setting: IOA Madrid Innova Ocular, Madrid, Spain. Design: Prospective comparative cohort study. Methods: A Topcon KR8800 autorefractor, based on a Scheiner double-pinhole, and a NIDEK OPD-SCAN III aberrometer, based on the scanning-slit retinoscopy principle, were used to obtain objective refraction (ObjRx) readings. In addition, lower-order Zernike coefficients (Z) were used to calculate ObjRx. A set of 7 different results in power vector notation [M(spherical equivalent), J0 and J45] for 7 different methods was obtained: Rx, AR (automated refraction obtained with the KR8800), WF-P (Z-based ObjRx for the photopic pupil), WF-M (Z-based ObjRx for the mesopic pupil), WF-4 (Z-based ObjRx for a 4 mm pupil), OPD-C (automated refraction measured with the OPD under photopic conditions), and OPD-M (automated refraction measured with the OPD under mesopic conditions). Results: The study comprised 102 eyes from 51 cataract patients who underwent binocular implantation of the POD F IOL. All 6 objective methods yielded more negative M values than manifest refraction (Rx) (p < 0.001). As for the astigmatism components (J0 and J45), only AR (p = 0.003) and OPD-M (p < 0.001) differed significantly from Rx. The best and worst correlation for the M component were ICC=0.70 (for WF-M) and ICC=0.48 (WF-4). Conclusions: Objective methods tend to yield more negative sphere values than manifest refraction.