Abstract
PURPOSE: To investigate the effects of cylinder axis-flip after toric intraocular lens (TIOL) implantation on vision and patient-reported outcome measures (PROMs). SETTING: Teaching hospital in the United Kingdom. DESIGN: Post hoc analysis of data from patients who participated in a prospective randomized study of TIOLs. METHODS: Axis-flip was defined as a change in postoperative refractive cylinder (RC) axis of 90 ± 22.5 degrees from the preoperative biometric axis. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), residual RC, and CATPROM-5 and EQ-5D-3L quality-of-life scores were analyzed. RESULTS: At 6 months, axis-flip occurred in 29 (34.5%) of 84 eyes of which 28 had with-the-rule (WTR) astigmatism preoperatively. Mean (±SD) UDVA (logMAR) was 0.13 (0.16) in flipped cases (FCs) and 0.10 (0.14) in unflipped cases (UFs) ( P = .88). CDVA was 0.01 (0.11) in FC and was 0.00 (0.09) in UF ( P = .68). Mean RC was 0.74 diopters (D) (0.41) in FC and 0.93 D (0.47) in UF ( P = .08). Mean CATPROM-5 score was -6.22 (2.56) in FC and -5.52 (3.03) in UF ( P = .29). Mean EQ-5D-3L calibrated score was 0.89 (0.19) in FC and 0.85 (0.19) in UF ( P = .35). Retrospectively applying coefficients of adjustment to account for posterior corneal astigmatism (PCA) suggested that 6 eyes (21%) of FC with WTR might have avoided axis-flip. CONCLUSIONS: Axis flipping after TIOL implantation did not adversely influence visual acuity or PROMs scores. Most FC had WTR preoperatively. Adjusting for PCA might have reduced axis-flip in some of these eyes.