Effect of Residual Astigmatism on Visual Acuity Following Bifocal, Trifocal, and Extended Depth-of-Focus Intraocular Lens Implantation: A Retrospective Cohort Study.

INTRODUCTION: This study aimed to evaluate the effects of residual astigmatism magnitude and axis on visual outcomes after simultaneous vision intraocular lens (SVIOL) implantation. METHODS: This retrospective cohort study reviewed medical records of cataract patients who underwent implantation of bifocal, trifocal, or extended depth-of-focus (EDOF) IOLs. Patients were stratified by residual astigmatism magnitude (mild [0-0.50 D], moderate [0.75-1.00 D], high [1.25-1.50 D]) and axis (with-the-rule [WTR], against-the-rule [ATR], oblique). Uncorrected distance, intermediate, and near visual acuities (UDVA, UIVA, UNVA) and corrected distance visual acuity (CDVA) recorded at the 1-month postoperative visit were extracted for analysis. RESULTS: A total of 879 eyes from 879 patients were analyzed (bifocal: 497 [56.5%]; trifocal: 166 [18.9%]; EDOF: 216 [24.6%]). In the bifocal group, UDVA, UIVA, and UNVA worsened with increasing astigmatism (all P < 0.05), whereas CDVA declined only in the high-astigmatism subgroup (P < 0.05). In the trifocal group, mild astigmatism yielded better UDVA, UIVA, and UNVA than moderate or high astigmatism (all P < 0.05) and better CDVA than the high-astigmatism subgroup (P < 0.05). In the EDOF group, mild astigmatism outperformed moderate and high astigmatism in UDVA and UIVA (both P < 0.05) and high astigmatism in UNVA and CDVA (both P < 0.05). Trifocal IOLs with mild or moderate astigmatism achieved better intermediate and near vision than other IOL types, whereas EDOF IOLs outperformed bifocal IOLs in the high-astigmatism subgroup (all P < 0.05). Astigmatic axis did not independently predict visual acuity in stratified multiple linear regression (all P > 0.05). CONCLUSIONS: Mild-to-moderate astigmatism primarily impairs intermediate and near vision, with trifocal IOLs exhibiting greater tolerance, whereas high astigmatism degrades vision at all distances, a setting in which EDOF IOLs perform better. Astigmatic axis appears to exert little influence.