Promise and Challenge: The Lens Model as a Biomarker for Early Diagnosis of Alzheimer's Disease

Table 1

Studies on detecting A𝛽 in the lenses of patients with AD.

Title	Year & authors	Patients	Significance
Cytosolic β-amyloid deposition and supranuclear cataracts in lenses from people with Alzheimer’s disease	2003, Goldstein et al. [19]	AD patients	AD patients suffered from a specific type (supranuclear) of cataract; Aβ was present in the cytosol of supranucleus lens fibre cells of those people with AD.
Alzheimer’s disease amyloid-β links lens and brain pathology in Down’s syndrome	2010, Moncaster et al. [30]	Down syndrome (DS) subjects with early onset AD	Increased accumulation of Aβ in lenses caused cataract in DS; increased Aβ accumulation is a key pathogenic determinant linking lens and brain pathology in both DS and AD.
Absence of beta-amyloid in cortical cataracts of donors with and without Alzheimer’s disease	2013, Michael et al. [35]	AD patients	No Aβ was detected in lens samples from donors with AD.
Beta-amyloid, phospho-tau, and alpha-synuclein deposits similar to those in the brain are not identified in the eyes of Alzheimer's and Parkinson's disease patients	2013, Ho et al. [36]	AD patients	No Aβ was detected in the lenses of AD patients. Aβ does not aggregate in the eye in a manner analogous to the brain or is present at lower levels or in different forms.
Alzheimer’s disease diagnosis by detecting exogenous fluorescent signal of ligand bound to beta amyloid in the lens of human eye: an exploratory study	2013, Kerbage et al. [1]	AD patients	The specific fluorescent signature bound Aβ in the supranuclear areas was higher among AD patients as compared to controls; the deeper supranuclear region revealed higher signal as compared to other supranuclear regions; the SAPPHIRE System can aid diagnosis of probable AD by detecting the presence of Aβ in vivo of human lens.