Table 2.

Abnormalities detected in the visual pathway of AD patients.

Visual changes	Manifestations	References
Visual acuity	Visual acuity changes reported in AD patients	[50, 51]
Contrast sensitivity	Several studies have reported changes in contrast sensitivity in Alzheimer's patients compared to controls	[48, 52, 53]
Colour vision	Although controversial, many studies have demonstrated colour vision deficiencies in AD patients, others reporting prevalence to be high	[54–56]
Visual field	There are reports to suggest that AD patients exhibit visual field defects	[57, 58]
Pupillary function	AD patients have exhibited atypical pupil response to cholinergic agonists and antagonists	[59, 60]
Lens	AD patients appear to be predisposed to a particular type of cataract (equatorial supranuclear)	[61]
Retina	AD patients have been shown to have a specific pattern of RNFL thinning, perhaps related to the severity of AD. Also shown to have decreased retinal blood flowChanges in retinal function using electrophysiological tests (PERGs and VEPs) have been shownAβ plaques have been demonstrated in the retinas of AD patients	[62–70]