title: A comparable study of clinical and optical outcomes after 1.8, 2.0 mm microcoaxial and 3.0 mm coaxial cataract surgery.
abstract: OBJECTIVE
  To evaluate the clinical and optical outcomes after clear corneal incision cataract surgery (CICS) with three different incision sizes (1.8, 2.0 and 3.0 mm).
  
  
  METHODS
  Eyes of 150 patients with age-related cataract scheduled for coaxial cataract surgery were randomized to three groups: 1.8, 2.0, or 3.0 mm CICS. Intraoperative data and postoperative outcomes including surgically induced astigmatism (SIA), the corneal incision thickness, wavefront aberrations and modulation transfer function (MTF) of cornea were obtained.
  
  
  RESULTS
  There were no significant differences among the three groups in demographic characteristics and intraoperative outcome. The 1.8 and 2.0 mm microincisions showed more satisfactory clinical outcomes than the 3.0 mm incision. The 1.8 mm incision showed significantly less SIA than the 2.0 mm incision until postoperative 1mo (P<0.05), but the difference was only 0.14-0.18 D. Combined with less increased incision thickness only at postoperative 1d (P=0.013), the 1.8 mm incision presented better uncorrected distance visual acuity (UCDVA) than the 2.0 mm incision only at 1d postoperatively (P=0.008). For higher-order aberrations and other Zernike coefficients, there were no significant differences between the 1.8 mm group and 2.0 mm group (P>0.05).
  
  
  CONCLUSIONS
  Converting from 3.0 mm CICS to 1.8 or 2.0 mm CICS result in better clinical and optical outcomes. However, when incision is 1.8 mm, the benefits from further reduction in size compared with 2.0 mm are limited. The necessity to reduce the incision size is to be deliberated.
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Yi-Bo
authors.initials: YB
authors.lastname: Yu
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Zhu
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Yi-Dong
authors.initials: YD
authors.lastname: Zhang
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Yin-Hui
authors.initials: YH
authors.lastname: Yu
authors.affiliation: Eye Center, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Yao
keywords: microsurgery; phacoemulsification; treatment outcome