title: Determining the size of retinal features in prematurely born children by fundus photography.
abstract: OBJECTIVE
  The purpose was to study the effect of prematurity on the macula-disc centre distance and whether it could be used as a reference tool for determining the size of retinal features in prematurely born children by fundus photography.
  
  
  METHODS
  The macula-disc centre distance of the left eye was measured in pixels from digital fundus photographs taken from 27 prematurely born children aged 10-11 years with Topcon fundus camera. A conversion factor for Topcon fundus camera (194.98 pixel/mm for a 50° lens) was used to convert the results in pixels into metric units.
  
  
  RESULTS
  The macula-disc centre distance was 4.74 mm, SD 0.29. No correlation between ametropia and the macula-disc centre distance was found (r = -0.07, p > 0.05). One child (subject 20) had high myopia and retinopathy of prematurity (ROP), and the macula-disc centre distance was longer than average (6.35 mm).
  
  
  CONCLUSIONS
  The macula-disc centre distance in prematurely born children at the age of 10-11 years provides an easy-to-use reference tool for evaluating the size of retinal features on fundus photographs. However, if complications of ROP, for example temporal macular dragging or high ametropia, are present, the macula-disc centre distance is potentially altered and a personal macula-disc centre distance should be determined and used as a refined reference tool.
authors.affiliation: Department of Ophthalmology, Satakunta Central Hospital, Pori, Finland.|Department of Ophthalmology, Turku University Hospital, Turku, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Knaapi
authors.affiliation: Department of Ophthalmology, Turku University Hospital, Turku, Finland.
authors.forename: Tuomo
authors.initials: T
authors.lastname: Lehtonen
authors.affiliation: Department of Ophthalmology, Turku University Hospital, Turku, Finland.
authors.forename: Eija
authors.initials: E
authors.lastname: Vesti
authors.affiliation: Department of Ophthalmology, Turku University Hospital, Turku, Finland.
authors.forename: Markku T
authors.initials: MT
authors.lastname: Leinonen
mesh_terms: D058452:Axial Length, Eye; D001724:Birth Weight; D002648:Child; D003941:Diagnostic Techniques, Ophthalmological; D005865:Gestational Age; D006801:Humans; D007234:Infant, Premature; D008266:Macula Lutea / Q000033:anatomy & histology / Q000473:pathology*; D009898:Optic Disk / Q000033:anatomy & histology / Q000473:pathology*; D010781:Photography / Q000379:methods*; D012016:Reference Values; D012178:Retinopathy of Prematurity / Q000175:diagnosis*
keywords: blind spot; fundus photography; macula-disc centre distance; prematurely born children; retinal feature