title: Evidence of early ultrastructural photoreceptor abnormalities in light-induced retinal degeneration using spectral domain optical coherence tomography.
abstract: BACKGROUND
  To study spatiotemporal in vivo changes in retinal morphology and quantify thickness of retinal layers in a mouse model of light-induced retinal degeneration using spectral domain optical coherence tomography (SD-OCT).
  
  
  METHODS
  BALB/c mice were exposed to 5000 lux of constant light for 3 h. SD-OCT images were taken 3 h, 24 h, 3 days, 1 week and 1 month after light exposure and were compared with histology at the same time points. SD-OCT images were also taken at 0, 1 and 2 h after light exposure in order to analyse retinal changes at the earliest time points. The thickness of retinal layers was measured using the Bioptigen software InVivoVue Diver.
  
  
  RESULTS
  SD-OCT demonstrated progressive outer retinal thinning. 3 h after light exposure, the outer nuclear layer converted from hyporeflective to hyper-reflective. At 24 h, outer retinal bands and nuclear layer demonstrated similar levels of hyper-reflectivity. Significant variations in outer retinal thickness, vitreous opacities and retinal detachments occurred within days of injury. Thinning of the retina was observed at 1 month after injury. It was also determined that outer nuclear layer changes precede photoreceptor segment structure disintegration and the greatest change in segment structure occurs between 1 and 2 h after light exposure.
  
  
  CONCLUSIONS
  Longitudinal SD-OCT reveals intraretinal changes that cannot be observed by histopathology at early time points in the light injury model.
authors.affiliation: Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Mehak K
authors.initials: MK
authors.lastname: Aziz
authors.affiliation: Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Ni
authors.affiliation: Departments of Medicine, Division of General Medicine and Clinical Epidemiology and Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Denise A
authors.initials: DA
authors.lastname: Esserman
authors.affiliation: Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Sai H
authors.initials: SH
authors.lastname: Chavala
mesh_terms: D000818:Animals; D005260:Female; D008027:Light / Q000009:adverse effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D020419:Photoreceptor Cells, Vertebrate / Q000648:ultrastructure*; D011833:Radiation Injuries, Experimental / Q000209:etiology / Q000473:pathology*; D012160:Retina / Q000528:radiation effects*; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology*; D041623:Tomography, Optical Coherence
keywords: Anatomy; Apotosis; Degeneration; Experimental &#8211 animal models; Imaging