title: Analysis of corneal spherical aberration in patients before and after phacoemulsification.
abstract: OBJECTIVE
  To investigate the distribution and changes in corneal four-order spherical aberration Z40 in patients with age-related cataract before and after phacoemulsification, and to direct the application of aspherical intraocular lens (IOL) in PHACO combined with IOL implantation.
  
  
  METHODS
  A total of 155 eyes in 93 patients with age-related cataract were included. All patients received a comprehensive ophthalmologic examination. Corneal Z40 at a pupil diameter of 6 mm was measured by using a Scheimpflug photography system (Pentacam) preoperatively and 3 months postoperatively.
  
  
  RESULTS
  The mean corneal Z40 before and after the PHACO at a diameter of 6 mm was (0.294±0.138) μm and (0.271±0.130) μm, respectively, with statistical significance (P<0.05，t=4.384). There was no significant difference between male (n=45, 76 eyes) and female patients (n=48, 79 eyes) regarding corneal Z40 (t=-0.418, P=0.676). The corneal Z40 for patients (35 eyes) aged from 50 to 59 years was (0.238±0.104) μm preoperatively; (0.308±0.104) μm for 60 to 69 years; (0.332±0.151)μm for 70 to 79 years; and (0.307±0.164) μm for 80 to 89 years. A significant difference in Z40 was observed among different age groups. A linear positive correlation was noted between corneal Z40 and ages (r=0.203, P<0.003).
  
  
  CONCLUSIONS
  The corneal Z40 varied significantly among cataract patients. Patients'corneal Z40, which should be considered when choosing aspherical IOL, increases slightly with age. Thus, customized aspheric IOLs are needed.
authors.affiliation: Department of Ophthalmology,Chinese PLA General Hospital,Beijing 100853,China.
authors.forename: Zhao Hui
authors.initials: ZH
authors.lastname: Li
authors.forename: Lie Xi
authors.initials: LX
authors.lastname: Jia
authors.forename: Yi Fei
authors.initials: YF
authors.lastname: Huang
mesh_terms: D057128:Aberrometry / Q000379:methods; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000503:physiopathology*; D015350:Contrast Sensitivity; D057108:Corneal Wavefront Aberration / Q000175:diagnosis*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011184:Postoperative Period; D011446:Prospective Studies; D012737:Sex Factors; D014792:Visual Acuity