title: Birth weight and optic nerve head parameters.
abstract: OBJECTIVE
  To assess the relationship of birth weight, birth length, and head circumference as proxy markers of intrauterine growth, cup/disc ratio, and other optic disc parameters measured using optical coherence tomography (OCT).
  
  
  METHODS
  Population-based cross sectional analysis.
  
  
  METHODS
  The Sydney Childhood Eye Study examined 2353 primarily 12-year-old children from 21 randomly selected secondary schools during 2003 to 2005.
  
  
  METHODS
  Of 2353 children examined, 2134 (90.7%) had OCT scans (Zeiss Stratus OCT, Carl Zeiss Meditec, Dublin, CA) and are included in this study. The "fast" optic disc scan protocol was used. Birth weight, birth length, and head circumference were ascertained from health records. Height and weight were measured using standardized protocols, body mass index (BMI) was defined as weight (kilograms)/ height squared (meters), and sociodemographic information was collected in a questionnaire completed by parents. Low birth weight was defined as birth weight <or=2499 g, and prematurity was defined as gestation less than 37 weeks. Logistic and mixed model analyses were performed.
  
  
  METHODS
  Vertical optic disc and optic cup diameters, and cup/disc ratio.
  
  
  RESULTS
  Children of low birth weight had decreased vertical disc diameter, increased cup diameter, and increased cup/disc ratio by 30 microm (P = 0.009), 44 microm (P = 0.004), and 0.03 (P<0.0001), respectively. After adjusting for age, gender, ethnicity, height, axial length, and BMI, birth weight remained positively associated with vertical optic disc diameter and inversely associated with both vertical optic cup diameter and vertical cup/disc ratio (each kilogram increase was associated with a 0.0133-mm larger mean disc diameter; P = 0.04; a 0.0203-mm smaller mean cup diameter; P = 0.02; and a 0.0136 reduction in mean cup/disc ratio; P = 0.002). These associations were not present in children with gestational age less than 33 weeks. Smaller birth length and head circumference were similarly associated with larger cup/disc ratio.
  
  
  CONCLUSIONS
  Low birth weight, short birth length, and small head circumference at birth were associated with larger cup/disc ratio in children aged 12 years. Our findings suggest that fetal growth restriction could adversely influence optic nerve head parameters. This may have implications for future risk of glaucomatous optic neuropathy.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, New South Wales, Australia.
authors.forename: Chameen
authors.initials: C
authors.lastname: Samarawickrama
authors.forename: Son C
authors.initials: SC
authors.lastname: Huynh
authors.forename: Gerald
authors.initials: G
authors.lastname: Liew
authors.forename: George
authors.initials: G
authors.lastname: Burlutsky
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D001724:Birth Weight; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D047109:Fetal Development; D005317:Fetal Growth Retardation / Q000175:diagnosis*; D006257:Head / Q000254:growth & development; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D009898:Optic Disk / Q000473:pathology*; D012029:Refraction, Ocular / Q000502:physiology; D011795:Surveys and Questionnaires; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology