title: Retinal nerve fiber layer thickness in amnestic mild cognitive impairment: Case-control study and meta-analysis.
abstract: BACKGROUND
  Retinal structural changes in subjects with mild cognitive impairment (MCI) remain a subject of controversy.
  
  
  METHODS
  We investigated the correlation between optical coherence tomography (OCT) of the retinal sublayers, including the retinal nerve fiber layer (RNFL), and cognitive function in subjects with amnestic MCI and compared the OCT findings with matched controls. We also performed a meta-analysis of the world literature using a random-effects model.
  
  
  RESULTS
  We found no statistically significant differences in OCT between amnestic MCI (aMCI) and controls. In aMCI subjects, we found an inverse relationship between RNFL thickness and two cognitive tests (delayed story recall and a word-list learning test and the word-list test). The meta-analysis revealed a statistically significant decrease in RNFL thickness in MCI subjects.
  
  
  CONCLUSIONS
  The inverse relationship between cognitive testing and RNFL thickness suggests that retinal involvement may include paradoxically increased thickness of the RNFL, which could suggest gliotic reactive changes.
authors.affiliation: Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Brianna
authors.initials: B
authors.lastname: Knoll
authors.affiliation: Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Simonett
authors.affiliation: Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Volpe
authors.affiliation: Department of Biomedical Engineering and Ophthalmology, Duke University, Durham, NC, USA.
authors.forename: Sina
authors.initials: S
authors.lastname: Farsiu
authors.affiliation: Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Mallory
authors.initials: M
authors.lastname: Ward
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Alfred
authors.initials: A
authors.lastname: Rademaker
authors.affiliation: Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Weintraub
authors.affiliation: Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Amani A
authors.initials: AA
authors.lastname: Fawzi
keywords: Alzheimer's disease; Biomarkers; Mild cognitive impairment; Optical coherence tomography; Retinal nerve fiber layer