title: Time course of corneal biomechanical parameters after phacoemulsification with intraocular lens implantation.
abstract: OBJECTIVE
  To assess the time course of corneal biomechanical parameters after phacoemulsification with intraocular lens implantation.
  
  
  METHODS
  We examined 54 eyes of 33 consecutive patients undergoing cataract surgery. We quantitatively assessed the values of corneal biomechanics characterized by corneal hysteresis (CH) and corneal resistance factor (CRF) using an Ocular Response Analyzer before and 1 day, 1 week, 1 month, and 3 months after surgery. We also investigated the relationship between these biomechanical parameters and central corneal thickness 3 months after surgery.
  
  
  RESULTS
  The CH was 9.7 ± 1.1 (mean ± SD) mm Hg preoperatively, and 9.0 ± 1.4, 9.7 ± 1.1, 9.7 ± 1.1, and 9.7 ± 1.3 mm Hg 1 day, 1 week, 1 month, and 3 months postoperatively, respectively. The CRF was 9.5 ± 1.1 mm Hg preoperatively, and 8.8 ± 1.2, 9.2 ± 1.3, 9.1 ± 0.9, and 9.2 ± 1.2 mm Hg 1 day, 1 week, 1 month, and 3 months postoperatively, respectively. Multiple comparisons demonstrated significant differences between measurements made before and 1 day after surgery (P = 0.01 for CH and CRF, Dunnett test). Both CH and CRF were significantly correlated with central corneal thickness (Pearson correlation coefficient r = 0.29; P = 0.03 for CH and r = 0.42; P = 0.002 for CRF).
  
  
  CONCLUSIONS
  Both CH and CRF decreased briefly at 1 day after cataract surgery but soon recovered to the preoperative levels, suggesting that cataract surgery does not induce a significant change in corneal biomechanics, except for 1 day postoperatively. The corneal thickness may play some role in corneal biomechanics even in postcataract eyes.
authors.affiliation: From the Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kamiya
authors.forename: Kimiya
authors.initials: K
authors.lastname: Shimizu
authors.forename: Fumiko
authors.initials: F
authors.lastname: Ohmoto
authors.forename: Rie
authors.initials: R
authors.lastname: Amano
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D002387:Cataract Extraction / Q000379:methods*; D003187:Compliance; D003315:Cornea / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011184:Postoperative Period; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography