Influence of simple myopic against-the-rule and with-the-rule astigmatism on visual acuity in eyes with monofocal intraocular lenses

Purpose To analyze the influence of simple myopic against-the-rule (ATR) and with-the-rule (WTR) astigmatism on uncorrected distance visual acuity (UDVA) in eyes after monofocal intraocular lens (IOL) implantation. Methods Patients with a postoperative spherical refractive error within +/- 0.5 diopter (D) and a negative cylindrical refractive error >= 0.5 D were enrolled and divided into two groups: ATR or WTR astigmatism. Age, pupil size, spherical equivalent refractive error, spherical refractive error, cylindrical refractive power, UDVA, corrected distance visual acuity (CDVA) and ocular wavefront aberrations were compared between groups. Correlations between UDVA and other parameters were also examined within groups. Results Twenty-five eyes (25 patients) with ATR astigmatism and 18 eyes (18 patients) with WTR astigmatism were evaluated. The logMAR UDVA was 0.30 +/- 0.22 (mean +/- SD) in the ATR group and 0.11 +/- 0.15 in the WTR group, showing a significant difference between groups (P<0.01). There were no significant differences in other parameters between groups. The UDVA was significantly correlated with spherical equivalent refractive error (r = -0.51, P<0.01) and cylindrical refractive power (r = -0.48, P = 0.01) in the ATR group, but not in the WTR group. No other parameters were significantly correlated with UDVA in either group. Conclusion After monofocal IOL implantation, UDVA in eyes with simple myopic ATR astigmatism was worse than in eyes with simple myopic WTR astigmatism. Additionally, UDVA was significantly influenced by cylindrical refractive power in eyes with ATR astigmatism, but not in eyes with WTR astigmatism.