Eyeworld

WINTER 2024 | EYEWORLD | 17 The authors also discussed further sub-anal- ysis of their patient data retroactively calcu- lating TIOL power given consideration of PCA, which was not measured or considered in preoperative planning during the initial pro- spective trial. They determined that for both UF with preoperative ATR astigmatism and FC with preoperative WTR astigmatism, there was a sig- nificant reduction in calculator-recommended TIOL cylindrical powers when PCA was consid- ered. This reaffirmed the understanding that PCA is typically greater vertically, inducing a larger minus lens effect in the vertical axis and therefore shifting any residual postoperative cylinder ATR. This leads to interesting discus- sion on age-related drift to ATR astigmatism and how future studies may provide more basis 0.00 [unflipped]) and refractive cylinder (0.74 [flipped] vs. 0.93 [unflipped]). Quality of life measures CATPROM-5 and EQ-5D-3L were similar as well. Among the flipped group, 28 eyes flipped from with-the-rule (WTR) to ATR, none flipped from ATR to WTR or OB, and 1 flipped from OB to OB. The mean change in axis was greater for the flipped group. Regarding vector analysis, the target induced astigmatism was similar, but the surgically induced astigmatism (SIA) was greater for the flipped group, 2.90 vs. 2.14. The difference vector and degrees of angle of error were not significantly different. The magnitude of error was greater in the flipped group, as was the correction index. The authors recalculated TIOL powers with adjustment for PCA and found that the recom- mended cylindrical power decreased for FC with preoperative WTR, while it increased for UC with ATR. Among FC, 6 eyes (21%) may have avoided axis-flip had PCA been adjusted for. In contrast, among UF, 2 eyes (4%) would have had axis-flip with PCA adjustment. Discussion In this post-hoc analysis of 84 patients from a prospective randomized study of toric intra- ocular lens outcomes, Naderi et al. set out to determine the effects of cylinder axis-flip after TIOL insertion on visual acuity and patient-re- ported outcome measures (PROMs). This study sets out to challenge the common consideration of erring on the side of undercorrection of cylindrical axis during TIOL insertion to avoid possible negative outcomes with axis-flip. 5 The initial prospective study from which they per- formed their post hoc analysis included patients whose astigmatism was completely addressed with TIOL (in addition to the SIA from the main wound), while others were a combination of TIOL with an opposite clear corneal incision. Ultimately, their study did not reveal any dif- ference in UDVA, CDVA, or any of the 3 utilized PROMs between flipped and unflipped cases. Interestingly, despite the accepted notion that WTR is better tolerated than ATR, there were no differences in vision or PROMs despite 28/29 (96.6%) FCs that were originally WTR that flipped to ATR. Maggie Xing, MD, John Wilson, MD, Eli Pratte, MD Source: Washington University School of Medicine in St. Louis continued on page 18

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