title: Variations in eye volume, surface area, and shape with refractive error in young children by magnetic resonance imaging analysis.
abstract: OBJECTIVE
  To determine variations in eye volume, surface area, and shape with refractive error in young children using a three-dimensional magnetic resonance imaging (MRI) model.
  
  
  METHODS
  A subset of Singaporean Chinese boys enrolled in the population-based Strabismus, Amblyopia, and Refractive Error in Singapore (STARS) study underwent MRI using a 3-Tesla whole body scanner with a 32-channel head coil. Eye volume and surface area were measured. Eye shape was assessed qualitatively from the three-dimensional models and quantitatively by measurement of the longitudinal axial length (LAL), horizontal width, and vertical height along the cardinal axes.
  
  
  RESULTS
  One hundred thirty-four eyes of 67 subjects (mean age, 77.9 ± 3.9 months) were analyzed. The mean spherical equivalent (SE) refraction was 0.65 ± 0.92 D (range, -2.31 to 4.13 D). More myopic SE was associated with larger surface area (-20.59 [-37.09 to -4.10] mm²/D; P = 0.01) but not volume. In age-height adjusted models, more myopic SE was associated with longer LAL (-1.94 [-2.47 to -1.41] mm/D; P < 0.001) and greater width (-1.12 [-1.26 to -0.99] mm/D; P < 0.001) but not height (0.64 [-2.55 to 3.82] mm/D; P = 0.70). In nonmyopic subjects, less hyperopic SE was associated with longer AL (-0.40 [-0.71 to -0.10] mm/D; P = 0.01), width (-0.59 [-0.84 to -0.34] mm/D; P < 0.001), and height (-0.40 [-0.64 to -0.17] mm/D; P = 0.001). In three-dimensional models, myopic eyes conformed to an axial elongation model with a prolate profile in the axial plane, whereas nonmyopic eyes showed global expansion.
  
  
  CONCLUSIONS
  Eye surface area increases with myopia in young children. Eye shape is different in myopia, even in its early stages. Axial globe enlargement occurs in myopic eyes leading to a prolate shape, whereas nonmyopic eyes enlarge globally in length, width, and height.
authors: Singapore Eye Research Institute, Singapore.
authors: Laurence S
authors: LS
authors: Lim
authors: Xianfeng
authors: X
authors: Yang
authors: Gus
authors: G
authors: Gazzard
authors: Xiaoyu
authors: X
authors: Lin
authors: Chelvin
authors: C
authors: Sng
authors: Seang-Mei
authors: SM
authors: Saw
authors: Anqi
authors: A
authors: Qiu
mesh_terms: D000550:Amblyopia / Q000208:ethnology / Q000473:pathology; D000886:Anthropometry / Q000379:methods; D044466:Asian People / Q000706:statistics & numerical data*; D002648:Child; D005123:Eye / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009216:Myopia / Q000208:ethnology* / Q000473:pathology*; D009929:Organ Size; D012307:Risk Factors; D013285:Strabismus / Q000208:ethnology / Q000473:pathology