**1. Introduction**

Up to more than one-third of cataract patients have preoperative corneal astigmatism of more than 1.0 diopter (D) [1], while 26.2% have more than 1.5 D [2, 3], 8–14.9% have more than 2.0 [1, 3], and 2.6–7.4% have more than 3.0 D [1, 3]. Astigmatism is one of the most important factors that affect postoperative vision quality. More than 0.5 D of residual astigmatism can reduce visual performance and patient satisfaction [4–6]. Currently, implanting a toric lens is recognized as the most accurate form of astigmatic correction during cataract surgery, especially astigmatism of more than 1 D [7]. Actually, toric IOLs correct preexisting regular corneal astigmatism usually ranging from 0.75 to 4.75 D [8]. However, the outcomes after toric IOL implantation are still influenced by many factors including accurate preoperative measurement of corneal astigmatism, IOL selection, marking techniques, intraoperative alignment and postoperative care, etc.
