title: Quantitative evaluation of changes in eyeball shape in emmetropization and myopic changes based on elliptic fourier descriptors.
abstract: OBJECTIVE
  To evaluate changes in eyeball shape in emmetropization and myopic changes using magnetic resonance imaging (MRI) and elliptic Fourier descriptors (EFDs).
  
  
  METHODS
  The subjects were 105 patients (age range, 1 month-19 years) who underwent head MRI. The refractive error was determined in 30 patients, and eyeball shape was expressed numerically by principal components analysis of standardized EFDs.
  
  
  RESULTS
  In the first principal component (PC1; the oblate-to-prolate change), the proportion of variance/total variance in the development of the eyeball shape was 76%. In all subjects, PC1 showed a significant correlation with age (Pearson r = -0.314; P = 0.001), axial length (AL, r = -0.378; P < 0.001), width (r = -0.200, P = 0.0401), oblateness (r = 0.657, P < 0.001), and spherical equivalent refraction (SER, r = 0.438; P = 0.0146; n = 30). In the group containing patients aged 1 month to 6 years (n = 49), PC1 showed a significant correlation with age (r = -0.366; P = 0.0093). In the group containing patients aged 7 to 19 years (n = 56), PC1 showed a significant correlation with SER (r = 0.640; P = 0.0063).
  
  
  CONCLUSIONS
  The main deformation pattern in the development of the eyeball shape from oblate to prolate was clarified by quantitative analysis based on EFDs. The results showed clear differences between age groups with regard to changes in the shape of the eyeball, the correlation between these changes, and refractive status changes.
authors: Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan. ishii_k@md.tsukuba.ac.jp
authors: Kotaro
authors: K
authors: Ishii
authors: Hiroyoshi
authors: H
authors: Iwata
authors: Tetsuro
authors: T
authors: Oshika
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D058453:Emmetropia / Q000502:physiology*; D005123:Eye / Q000473:pathology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D008954:Models, Biological; D009216:Myopia / Q000473:pathology* / Q000503:physiopathology*; D009799:Ocular Physiological Phenomena; D012189:Retrospective Studies; D055815:Young Adult