title: Foveal avascular zone and foveal pit formation after preterm birth.
abstract: BACKGROUND
  Vascularisation of the macula takes place between 24 and 27 weeks post-conception. Preterm birth may affect the formation of the foveal avascular zone (FAZ) and foveal depression, and displacement of inner retinal layers away from the incipient fovea.
  
  
  OBJECTIVE
  To examine whether vascular abnormalities accompany an inner retinal abnormality, and whether they are coincident.
  
  
  METHODS
  High-density spectral domain optical coherence tomography volume scans were obtained from 24 preterm children and 34 full-term controls (5-16 years). Matlab programs were used to quantify total retinal thickness, thickness of individual retinal layers and metrics of foveal morphology. Summed voxel projections for the ganglion cell layer-inner nuclear layer were used to identify the FAZ.
  
  
  RESULTS
  Preterm children had significantly smaller FAZ diameters than controls (p<0.0001). The foveal pits of preterm children were significantly shallower and less steep (p<0.0001) and total retinal thickness at the fovea was significantly increased (p<0.0001) compared to controls. The ganglion cell layer-inner plexiform layer and outer nuclear layer were significantly (p≤0.0001) thicker in preterm children than in controls.
  
  
  CONCLUSIONS
  Preterm birth results in abnormal foveal vascularisation, a failure of the inner retinal neurons to migrate away from the fovea, and an elevated outer nuclear layer ratio. The spatial coincidence of inner retinal and vascular abnormalities in preterm children supports the hypothesis that aspects of foveal development are interdependent.
authors.affiliation: Retina Foundation of the Southwest, 9900 North Central Expressway, Suite 400, Dallas, TX 75231-0920, USA. susan.e.yanni@gmail.com
authors.forename: Susan E
authors.initials: SE
authors.lastname: Yanni
authors.forename: Jingyun
authors.initials: J
authors.lastname: Wang
authors.forename: Melody
authors.initials: M
authors.lastname: Chan
authors.forename: Joseph
authors.initials: J
authors.lastname: Carroll
authors.forename: Sina
authors.initials: S
authors.lastname: Farsiu
authors.forename: Joel N
authors.initials: JN
authors.lastname: Leffler
authors.forename: Rand
authors.initials: R
authors.lastname: Spencer
authors.forename: Eileen E
authors.initials: EE
authors.lastname: Birch
mesh_terms: D000293:Adolescent; D001724:Birth Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D005584:Fovea Centralis / Q000002:abnormalities* / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007231:Infant, Newborn; D017075:Laser Coagulation; D018919:Neovascularization, Physiologic; D009412:Nerve Fibers / Q000473:pathology; D011247:Pregnancy; D047928:Premature Birth; D012165:Retinal Ganglion Cells / Q000473:pathology; D015861:Retinal Neovascularization / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D012171:Retinal Vessels / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D047929:Term Birth; D041623:Tomography, Optical Coherence; D014786:Vision Disorders / Q000175:diagnosis; D014792:Visual Acuity / Q000502:physiology