title: Postoperative corneal shape changes: microincision versus small-incision coaxial cataract surgery.
abstract: OBJECTIVE
  To compare changes in corneal topography and in regular and irregular astigmatism after coaxial clear corneal microincision cataract surgery (MICS) and after coaxial small-incision cataract surgery (SICS).
  
  
  METHODS
  Hayashi Eye Hospital, Fukuoka, Japan.
  
  
  METHODS
  Induced corneal astigmatism was determined using vector analysis. The averaged corneal shape changes and degree of irregular astigmatism were examined using videokeratography preoperatively as well as 2 days and 1, 2, 4, and 8 weeks postoperatively.
  
  
  RESULTS
  One hundred twenty eyes of 60 patients scheduled for phacoemulsification were evaluated. Sixty eyes had MICS (2.00 mm), and the 60 contralateral eyes had SICS (2.65 mm). The mean induced corneal astigmatism was significantly less in the MICS group than in the SICS group (P <or= .0495) 1 week postoperatively and subsequently. The averaged difference map on videokeratography showed focal corneal flattening corresponding to the incision and coupled steepening around the flattened area 2 days postoperatively in both groups. The flattening and steepening gradually reduced to virtually the preoperative shape by 8 weeks; the changes were significantly less in the MICS group than in the SICS group. Of the irregular astigmatic components, higher-order irregularity was significantly less in the MICS group than in the SICS group up to 2 weeks postoperatively (P <or =.0470).
  
  
  CONCLUSIONS
  Induced astigmatism, focal wound-related flattening of the peripheral cornea, and corneal surface irregularity were significantly less after coaxial MICS than after SICS.
authors.affiliation: Hayashi Eye Hospital, Hakata-Ku, Fukuoka, Japan. hayashi-ken@hayashi.or.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Hayashi
authors.forename: Motoaki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000175:diagnosis* / Q000209:etiology; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods*; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D018918:Phacoemulsification / Q000379:methods*; D011183:Postoperative Complications; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology; D014945:Wound Healing