title: The genetic effect on refractive error and anterior corneal aberration: twin eye study.
abstract: OBJECTIVE
  To investigate the role of heredity in determining refractive variables, anterior corneal curvature, and anterior corneal aberrations.
  
  
  METHODS
  Thirty-three monozygotic and 10 dizygotic twin pairs were enrolled in this study. Corneal curvature, corneal astigmatism, and corneal topography were obtained from computerized videokeratoscope. The CTView program was used to compute anterior corneal aberrations from corneal height data of the videokeratoscope. Correlation analysis was performed to investigate the symmetry of the refractive error, corneal curvature, corneal astigmatism, and anterior corneal aberrations between right and left eyes of each twin pair. Heritability (h2) of these parameters was also calculated.
  
  
  RESULTS
  Positive correlations were noted between right and left eyes for spherical power, total astigmatism, mean corneal curvature, and corneal astigmatism. In monozygotic twins, vertical coma, secondary vertical coma, spherical aberration, and secondary spherical aberration were moderately correlated. In dizygotic twins, vertical coma, secondary horizontal coma, and spherical aberration were moderately correlated. In unrelated controls, secondary vertical coma, secondary horizontal coma, and secondary spherical aberration were moderately correlated. Root-mean-square (RMS) of higher order aberrations (3rd to 6th orders), RMS of spherical aberration, and RMS of coma were moderately correlated between right and left eyes in all three groups. Heritability of spherical aberration, RMS of spherical aberration, and corneal astigmatism (h2 = 0.56, 0.44, and 0.46) were greater than those of refractive power, corneal curvature, and other higher order aberrations.
  
  
  CONCLUSIONS
  These results suggest that corneal astigmatism and spherical aberration possess a greater genetic predisposition than those of other refractive errors and higher order aberrations.
authors: Department of Ophthalmology, Chang-Gung University College of Medicine.
authors: Lung-Kun
authors: LK
authors: Yeh
authors: Cheng-Jen
authors: CJ
authors: Chiu
authors: Chieh-Fang
authors: CF
authors: Fong
authors: I-Jong
authors: IJ
authors: Wang
authors: Wei-Li
authors: WL
authors: Chen
authors: Chuhsing Kate
authors: CK
authors: Hsiao
authors: Samuel C M
authors: SC
authors: Huang
authors: Yung-Feng
authors: YF
authors: Shih
authors: Fung-Rong
authors: FR
authors: Hu
authors: Luke L K
authors: LL
authors: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000235:genetics*; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*