title: Corneal biomechanical properties changes after coaxial 2.2-mm microincision and standard 3.0-mm phacoemulsification.
abstract: OBJECTIVE
  To compare the changes in corneal biomechanics measured by ocular response analyzer (ORA) after 2.2-mm microincision cataract surgery and 3.0-mm standard coaxial phacoemulsification.
  
  
  METHODS
  The prospective nonrandomized study comprised eyes with cataract that had 2.2-mm coaxial microincision or 3.0-mm standard incision phacoemulsification. The corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) were measured by ORA preoperatively and at 1d, 1-, 2-, 3- and 4-week postoperatively. Results were analyzed and compared between groups.
  
  
  RESULTS
  In both groups, CH decreased in the immediate postoperative period (P<0.05), returned to the preoperative level at one week (P=0.249) in the 2.2-mm group, and at two weeks in the 3.0-mm group (P=0.264); there was no significant change in CRF values. In 2.2-mm group, mean IOPcc and IOPg increased at 1d postoperatively (both P<0.05), and returned to preoperative level at one week (P=0.491 and P=0.923, respectively). In 3.0-mm group, mean IOPcc and IOPg increased at 1d and 1wk postoperatively (P=0.005 and P=0.029, respectively), and returned to preoperative level at 2wk (P=0.347 and P=0.887, respectively).
  
  
  CONCLUSIONS
  Significant differences between preoperative and postoperative corneal biomechanical values were found for CH, IOPcc and IOPg. But the recovery time courses were different between the two groups. The 2.2-mm coaxial microincision cataract surgery group seemed recovery faster compared to the 3.0-mm standard coaxial phacoemulsification group.
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300070, China; Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yu
authors.affiliation: Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
authors.affiliation: Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China; Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
authors.forename: Ya-Ding
authors.initials: YD
authors.lastname: Jia
authors.affiliation: Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
authors.forename: Su-Hua
authors.initials: SH
authors.lastname: Zhang
keywords: 2.2-mm microincision; coaxial microincision cataract surgery; corneal biomechanical parameters; time course