title: [Distribution of human anterior corneal spherical aberration and its related factors].
abstract: OBJECTIVE
  To investigate the distribution of anterior corneal 4th-order spherical aberration in age-related cataract eyes of Chinese people and analyze its related factors, in order to guide the selection of intraocular lenses with modified spherical aberration profiles.
  
  
  METHODS
  After outputting anterior corneal curve and height data from the corneal topographic maps (Humphrey Carl Zeiss) of 188 eyes of 144 age-related cataract patients, corneal 4th-order spherical aberration was computed using ray-training calculation programs. Correlation analysis was performed between the spherical aberration and corneal curve, corneal astigmatism, corneal shape factor.
  
  
  RESULTS
  There was wide individual variability in corneal 4th-order spherical aberrations with ranges of individual Zernike terms from -0.096 microm to +0.469 microm. Three eyes had negative spherical aberration. The mean coefficient of the 4th-order spherical aberration was 0.231 +/- 0.092 microm (95% confidence interval [CI] = 0.217 - 0.244 microm). The spherical aberration was neither correlated with corneal curve(r = 0.134, P = 0.067) nor correlated with corneal astigmatism (r = -0.075, P = 0.304). High correlation was found between spherical aberration and shape factor (r = -0.725, P = 0.000).
  
  
  CONCLUSIONS
  Anterior corneal 4th-order spherical aberration varied greatly among cataract eyes and some eyes had negative spherical aberration. Spherical aberration was neither correlated with corneal curve nor correlated with corneal astigmatism. But high correlation was found between spherical aberration and shape factor. Customized aspheric intraocular lenses are needed and shape factor can give some advice to select customized intraocular lenses with modified spherical aberration profiles.
authors.affiliation: The Affiliated Eye Hospital of Wenzhou Medical College, Zhejiang Wenzhou 325000, China. zye@mail.eye.ac.cn
authors.forename: Nü-xia
authors.initials: NX
authors.lastname: Tong
authors.forename: Yun-e
authors.initials: YE
authors.lastname: Zhao
authors.forename: Qin-mei
authors.initials: QM
authors.lastname: Wang
authors.forename: Xing-yu
authors.initials: XY
authors.lastname: Li
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000453:epidemiology*; D003315:Cornea / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged