To compare the surgically induced posterior astigmatism of microcoaxial cataract surgery using a 2.2 mm incision and conventional cataract surgery using a 2.85 mm incision.

This study included 56 eyes that underwent phacoemulsification and intraocular lens insertion. Subjects were divided into 2 groups: 26 eyes receiving a microcoaxial cataract surgery using a 2.2 mm incision (MCCS group) and 30 eyes receiving a conventional cataract surgery using a 2.85 mm incision (CCS group). Anterior, posterior and total corneal astigmatism was measured. The surgically induced anterior astigmatism, surgically induced posterior astigmatism and surgically induced total astigmatism were compared between MCCS and CCS groups. Corneal astigmatism was measured using a Pentacam® device (Oculus, Wetzlar, Germany), uncorrected visual acuity, best corrected visual acuity and corneal aberrations of front and rear side was measured preoperatively and at 1 day, 1 month and 2 months postoperatively.

There was no difference in surgically induced posterior astigmatism between CCS and MCCS groups, however, surgically induced anterior astigmatism and surgically induced total astigmatism were significantly lower in the MCCS group than in the CCS group ( p = 0.005 and, p = 0.036, respectively). There was a significant positive linear correlation between surgically induced posterior astigmatism and surgically induced total astigmatism in the CCS group ( p = 0.01, r = 0.563). There was also a significant positive linear correlation between surgically induced anterior astigmatism and surgically induced total astigmatism in both CCS and MCCS groups (CCS group: p = 0.00, r = 0.855; MCCS group: p = 0.039, r = 0.407).

There was no significant difference in the surgically induced posterior astigmatism between the MCCS and CCS groups. However, surgically induced posterior astigmatism significantly affected surgically induced total astigmatism in the CCS group but not in the MCCS group. Considering both anterior and posterior astigmatism of the cornea, microcoaxial cataract surgery using a 2.2 mm incision affects surgically induced total astigmatism less than conventional cataract surgery.