Alzheimer's disease is a progressive brain disorder that destroys memory and thinking skills. It is now considered a major public health problem as the number of older Americans with Alzheimer's is expected to rapidly increase in coming decades. The hallmarks of Alzheimer's in the brain are beta-amyloid plaques and neurofibrillary tangles which disrupt neuron function and lead to shrinkage in areas important for memory and cognition. Early signs can include mild memory loss but the disease progresses to include problems with language, mood, and physical abilities until death, usually due to infection. Recent research also links some eye diseases to increased risk of Alzheimer's and finds signs of the disease's proteins and neurodegeneration in ocular structures.

1. ALZHEIMER'S
DISEASES

2. The Impact of AD
Once considered a rare disorder,
Alzheimer’s disease is now seen
as a major public health problem
that is seriously affecting
millions of older Americans and
their families
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3. WHAT IS ALZHEIMER’S
DISEASE
Alzheimer’s disease is an
irreversible, progressive
brain disease that slowly
destroys memory and
thinking skills.
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4. •AD is the most common cause of dementia among people age
65 and older.
•Current estimates (2017) suggest that 44 million people live
with dementia worldwide at present
•In England and Wales, dementia is the leading cause of death
overall, accounting for 11.6% of all deaths registered in 2015
•AD is the single biggest cause of dementia, accounting for 50%–
75%, and is primarily a condition of later life, roughly doubling
in prevalence every 5 years after age 65
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5. • For every 5-year age group beyond 65, the percentage of
people with AD doubles.
•By 2050, 13.2 million older Americans are expected to have AD
if the current numbers hold and no preventive treatments
become available.
Where are people with AD cared for?
•home
•assisted living facilities (those in the early stages)
•nursing homes (special care units)
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6. THE THREE MAIN PLAYERS
•Cerebral hemispheres
•Cerebellum
•Brain stem
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7. THE BRAIN ACTION
HEARING WORDS SPEAKING WORDS SEEING WORDS THINKING ABOUT
WORDS
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8. AD AND THE BRAIN
Plaques and Tangles: The Hallmarks of AD
The brains of people with AD have an abundance of two
abnormal structures:
•Beta-amyloid plaques, which are dense deposits of protein and
cellular material that accumulate outside and around nerve cells
•Neurofibrillary tangles, which are twisted fibers that build up
inside the nerve cell
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9. BETA-AMYLOID PLAQUES
Amyloid precursor protein (APP) is
the precursor to amyloid plaque.
1. APP sticks through the neuron
membrane.
2. Enzymes cut the APP into
fragments of protein, including
beta-amyloid.
3. Beta-amyloid fragments come
together in clumps to form
plaques
In AD, many of these clumps form,
disrupting the work of neurons. This
affects the hippocampus and other
areas of the cerebral cortex
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10. PET SCAN OF NORMAL AND
AD BRAIN
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11. Preclinical AD:
• Signs of AD -
entorhinal
cortex, then
proceed to the
hippocampus.
• Affected
regions begin
to shrink as
nerve cells die.
• Changes can
begin 10-20
years before
symptoms
appear
• Memory loss is
the first sign of
AD.
•Mild AD signs can
include memory loss,
confusion, trouble
handling money, poor
judgment, mood
changes, and
increased anxiety.
•Moderate AD signs
can include increased
memory loss and
confusion, problems
recognizing people,
difficulty with
language and
thoughts,
restlessness,
agitation, wandering,
and repetitive
statements.
Severe AD
• extreme shrinkage
occurs in the brain.
• Symptoms can
include weight
loss, seizures, skin
infections,
groaning,
moaning, or
grunting, increased
sleeping, loss of
bladder and bowel
control.
• Death usually
occurs from
aspiration
pneumonia or
other infections.
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12. AD AND THE EYE
• Alzheimer's disease is caused by an abnormal build-up of proteins in
the brain that kills cells and damages connections between neurons.
•Symptoms can also include vision problems, especially trouble with
spatial relationships and depth perception
•Some patients develop trouble reading, following moving objects, or
have problems with contrast
•Some people get mild cognitive impairment (MCI) in older age, which
may or may not get worse with time
•Right now, Alzheimer's disease is diagnosed after a series of
assessments and exams that rule out other things.
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13. • A recent study showed that people who have macular degeneration,
glaucoma or diabetic retinopathy are more likely to be diagnosed with
Alzheimer's disease than people without these conditions
•There is no cure for Alzheimer's disease, but some medicines and
lifestyle interventions may help people with the disease function well
for longer.
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14. Ocular Structures Pathological Changes in AD
Retina
- Deposition of proteins tau, Aβ and pTAu.
Impaired metabolism of amyloid β precursor
protein (APP)
- Reduction in retinal ganglion cells
-Reduction of retinal thickness
-Reduction in the retinal nerve fiber layer
thickness (RNFL)
-Retrograde degeneration secondary to loss
of cortical neurons
- Inflammation
Retinal and choroidal vasculature
-Retinal and choroidal vascular β-amyloid
deposits in transgenic mouse model of AD
lead to retinal degeneration
- Impaired vascularization
Retinal vascular blood flow
- Blood flow disturbances can lead to
neurodegeneration
Optic nerve
-Axonal degeneration in the axonal segments
-Loss of optic nerve thickness
-Papillary paleness due to axonal loss and
perfusion alterations
Lens
-Correlation between AD and supranuclear
cataract
- Presence of abnormal protein deposits
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15. Visual Function Pathological Changes in AD
Visual fields - Inferior hemi field loss
Visual acuity
- Decreased visual acuity in low
luminance
Sensory perception
- Clinically important symptoms of
visuospatial disorientation
Visual processing - Deficits of visual motion perception
Contrast sensitivity
- Contrast sensitivity disturbances and
motion perception
Color vision
- Color discrimination error inversely
proportional with mini-mental state
examination (MMSE) score
Stereopsis
- Reduced stereoscopic depth
perception
Circadian rhythm - Alterations in the circadian rhythm
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HTTPS://EYEWIKI.AAO.ORG/OCULAR_MANIFESTATIONS_OF_ALZHEIMER_DISEASE
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Tears
- Changes in the chemical barrier
composition of tears
Cornea - Reduced corneal sensitivity
Pupil
- Pupillary response, possible
biomarker
Choroid
- Attenuation of choroidal
thickness

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