Retinal thickness in Alzheimer's disease: A systematic review and meta-analysis

Jurre den Haan; Frank D Verbraak; Pieter Jelle Visser; Femke H Bouwman

doi:10.1016/j.dadm.2016.12.014

Retinal thickness in Alzheimer's disease: A systematic review and meta-analysis

Alzheimers Dement (Amst). 2017 Jan 25:6:162-170. doi: 10.1016/j.dadm.2016.12.014. eCollection 2017.

Authors

Jurre den Haan¹, Frank D Verbraak², Pieter Jelle Visser³, Femke H Bouwman¹

Affiliations

¹ Neurology, VU University Medical Center Alzheimer Center, Amsterdam, The Netherlands.
² Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Ophthalmology Department, VU University Medical Center, Amsterdam, The Netherlands.
³ Neurology, VU University Medical Center Alzheimer Center, Amsterdam, The Netherlands; Alzheimer Centre, School for Mental Health and Neuroscience (MHeNS), University Medical Centre, Maastricht, The Netherlands.

Abstract

Introduction: Retinal characteristics are increasingly recognized as biomarkers for neurodegenerative diseases. Retinal thickness measured by optical coherence tomography may reflect the presence of Alzheimer's disease (AD). We performed a meta-analysis on retinal thickness in AD and mild cognitive impairment (MCI) patients and healthy controls (HCs).

Methods: We selected 25 studies with measurements of retinal thickness including 887 AD patients, 216 MCI patients, and 864 HCs that measured retinal thickness. Outcomes were peripapillary retinal nerve fiber layer (RNFL) and macular thickness. The main outcome was the standardized mean differences (SMDs). We used STATA to perform the meta-analysis (StataCorp, Texas; version 14.0).

Results: Relative to HCs, AD and MCI patients had lower peripapillary RNFL (SMD 0.98 [CI -1.30, -0.66, P < .0001] and SMD 0.71 [CI -1.24, -0.19, P = .008]). Total macular thickness was decreased in AD patients (SMD 0.88 [CI -1.12, -0.65, P = .000]).

Discussion: Retinal thickness is decreased in AD and MCI patients compared to HC. This confirms that neurodegenerative diseases may be reflected by retinal changes.

Keywords: Alzheimer's disease (AD); Biomarkers; Eye; Meta-analysis; Mild cognitive impairment (MCI); Optical coherence tomography (OCT); Retinal thickness.