title: Evaluation of the chorioretinal thickness changes in Alzheimer's disease using spectral-domain optical coherence tomography.
abstract: BACKGROUND
  To assess the chorioretinal thickness changes using spectral-domain optical coherence tomography (SD-OCT) and to evaluate the association between these structural changes and cognitive impairment in Alzheimer's disease (AD).
  
  
  METHODS
  Prospective, cross-sectional study
  
  
  METHODS
  Thirty-one eyes of 31 consecutive patients with AD and 30 eyes of 30 cognitively healthy age-matched control subjects were recruited
  
  
  METHODS
  SD-OCT (RTVue-100) was used to measure the macular ganglion cell complex thickness (mGCC), outer retinal thickness (ORL), and the choroidal thickness (CT). Cognitive function was evaluated by Mini-Mental State examination (MMSE) on the same day of the optical examination.
  
  
  METHODS
  Chorioretinal thickness.
  
  
  RESULTS
  The mGCC average, mGCC superior and mGCC inferior thicknesses of the AD group were significantly thinner than those of the controls (all, P < 0.05). No significant difference was found in the ORL thickness measurements between the two groups. Compared with control subjects, the CT measurements at all regions were significantly thinner in patients with AD than controls except CT measurement at 3.0 mm temporal to the fovea (P = 0.067). Significant correlations between the mGCC thickness measurements of the AD group and MMSE scores were observed. There was no significant correlation between the MMSE scores and the CT measurements (P > 0.05).
  
  
  CONCLUSIONS
  Patients with AD had chorioretinal structural alterations. Retinal structural alterations were seen only in the inner layers. The reduction in mGCC thickness parameters were related to the severity of cognitive impairment in AD.
authors.affiliation: Ophthalmology Department, Bozok University Faculty of Medicine, Yozgat, Turkey.
authors.forename: Hasan Ali
authors.initials: HA
authors.lastname: Bayhan
authors.forename: Seray
authors.initials: S
authors.lastname: Aslan Bayhan
authors.forename: Asuman
authors.initials: A
authors.lastname: Celikbilek
authors.forename: Nermin
authors.initials: N
authors.lastname: Tanık
authors.forename: Canan
authors.initials: C
authors.lastname: Gürdal
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000150:complications* / Q000175:diagnosis; D002829:Choroid / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009412:Nerve Fibers / Q000473:pathology; D009929:Organ Size; D011446:Prospective Studies; D012160:Retina / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology; D041623:Tomography, Optical Coherence
keywords: Alzheimer's disease; choroidal thickness; ganglion cell complex; spectral-domain optical coherence tomography