Effect of residual astigmatism on uncorrected visual acuity and patient satisfaction in pseudophakic patients

PURPOSE To evaluate the effect of residual astigmatism on postoperative visual acuity and satisfaction after intraocular lens (IOL) surgery. SETTING Private practice, United Kingdom. DESIGN Retrospective case series. METHODS Postoperative data of patients who had previously undergone refractive lens exchange or cataract surgery were used in a multivariate regression model to assess the effect of residual astigmatism on 3 months postoperative monocular uncorrected distance visual acuity (UDVA) and patient satisfaction. The analysis was based on residual refraction in the dominant eye of each patient. Odds ratios were calculated to demonstrate the effect of increasing residual astigmatism on UDVA and satisfaction with separate calculations for monofocal and multifocal IOLs. RESULTS Three months postoperative outcomes of 17 152 dominant eyes were used in multivariate regression analysis. Compared with eyes with 0.00 diopter (D) residual astigmatism, the odds of not achieving 20/20 vision in eyes with 0.25 to 0.50 D residual astigmatism increased by a factor of 1.7 and 1.9 (P < .0001) in monofocal and multifocal IOLs, respectively. For the residual astigmatism 0.75 to 1.00 D, the odds ratio for not achieving 20/20 vision compared with eyes with no astigmatism was 6.1 for monofocal and 6.5 for multifocal IOLs (P < .0001). The effect of residual astigmatism on satisfaction was more evident at the 0.75 to 1.00 D level, where the odds of not being satisfied with vision increased by a factor of 2.0 and 1.5 in patients with monofocal and multifocal IOLs, respectively (P < .0001). The orientation of astigmatism was not a significant predictor in multivariate analysis. CONCLUSIONS Multivariate analysis in a large population of patients demonstrated that low levels of residual astigmatism can degrade visual acuity. Corneal astigmatism of 0.50 D or greater should be included in surgical planning.