Transcript Macular Degeneration

Macular Degeneration
Region 11
Description
Macular degeneration ,the
leading cause of vision loss
in our population of 60 years
of age and older, is a disease
that causes field loss in your
central vision. It affects the
macula (the area of the eye
that helps you differentiate
fine detail).
What parts are affected
and how?
The macula is part of the retina and is located at the
very back of the eye. The macula’s job is to process
sharp, clear, straight ahead vision. There are two forms
of macular degeneration, dry and wet.
Normal
Macula
Symptoms and Signs
Straight lines become distorted or blurry
Dark or white areas appear in your central
vision
Perception of color changes or decreases
Need brighter light to work
Hard to adapt to levels of low light
Printed words become blurry
Difficulty recognizing faces
Functional Implications
Makes reading and
driving harder
More difficult to
recognize faces
Central vision loss
Adult Forms
It occurs in 10% of people over 50 years of age
and 33% of people over 75 years of age.
1.2 million people with macular degeneration will
lose part of their central vision.
200,000 will have complete loss of central vision
in both eyes
Adult forms of macular degeneration can be
inherited or age-related macular degeneration
(AMD). The most prevalent forms are “wet” and
“dry”.
Wet Macular
Degeneration
•
Wet Macular Degeneration is not as common and only accounts for
about 10 percent of cases. This occurs when abnormal blood vessels
grow behind the macula, leaking fluid and blood, causing scaring on
the macula. Wet Macular Degeneration can happen very quickly.
Normal
Eye
Eye withWet
Macular
Degeneratio
n
Dry Macular
Degeneration
•
This is the most common form. Drusen are small white or yellow deposits that
sometimes build up in the back of the eye. These “spots” can prevent the lightsensing cells, called photoreceptors, in the retina from getting enough oxygen
or nutrients. When this occurs, the light-sensing cells can then become
damaged, which can lead to degeneration of the macula.
Normal Eye
Eye withDry
Macular
Degeneration
Juvenile Forms
Juvenile forms of macular degeneration are all
inherited. The most common forms are:
Stargardt’s (also called fundus flavimaculatus or
macular dystrophy) is the most common form.
Typical diagnoses occurs during the childhood or
teen years.
Best disease (also called vitelliform macular
degeneration) is the second most common form.
Typical diagnoses usually happens between birth
and 7 years of age.
Stargardt’s
Stargardt's disease is the most common form of inherited juvenile degeneration. It
is characterized by a reduction of central vision, but it preserves peripheral vision.
The progression of vision loss is variable and can start with a visual acuity of 20/40
and decrease to 20/200 (legal Blindness). By age 50, approximately 50% of all those
studied in clinical trials had visual acuities of 20/200 to 20/400. In late stages of this
disease there may also be color vision impairment.
Mutations in the ABCR4 gene, which cause Stargardt's disease, produce a
dysfunctional protein that cannot perform its transport function. As a result, photoreceptor
cells degenerate and vision loss occurs.
Currently there is no treatment for Stargardt's disease, but one will hopefully be
found in the near future.
Best Disease
Best disease (also known as vitelliform macular dystrophy) consists of a yellow cyst
that forms beneath the macula. In this case, visual acuity could remain nearly normal, 20/30
to 20/50, for many years. Peripheral vision also typically remains unaffected. In many cases,
the cyst will eventually rupture causing fluid and yellow deposits to spread throughout the
macula creating further vision loss, to about 20/100 later in life. Best disease does not always
affect both eyes equally.
This disease is passed through families by the autosomal dominant pattern of
inheritance. Therefore, if an affected individual has one Best gene paired with one normal
gene, there is a 50% chance that the affected parent will pass the disease-causing gene to each
child.
Currently, there is no treatment for Best disease.
Congenital and
Progressive
Juvenile Macular Degeneration is congenital
meaning it is passed down genetically.
It is also progressive, meaning it gets worse
over time.
Who is most at risk?
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Age -- Macular degeneration is the leading cause
of severe vision loss in people over 60.
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Gender -- Women are more likely to develop it
than men.
•
Cigarette smoking
•
Family history of macular degeneration
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Heart disease
•
High cholesterol
•
Light eye color
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Long-term exposure to sunlight
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Low levels of antioxidants in your blood
Treatments to slow the
progression
Take anti-oxidant
vitamins
Use sunglasses with
100% UV protection
Wear a hat or visor
Frequently test using
the Amsler grid
These treatments can
help slow the loss of
vision, but it cannot
be restored.
Amsler Grid
Amsler Grid with Macular
Degeneration
More Aggressive
Treatments
•
Drug Therapies
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For wet AMD, a type of medication called anti-vascular endothelial growth factor (anti-VEGF) can be injected into your
eye to stop new blood vessels from growing. Two such drugs are approved to treat AMD:
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Pegaptanib (Macugen) & Ranibizumab (Lucentis)
•
Surgical and Other Procedures
•
Surgical and other procedures may help some cases of wet macular degeneration.
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Photocoagulation (laser surgery) -- In photocoagulation, doctors use a laser to seal off blood vessels that have grown
under the macula. Whether this procedure is used depends on where the blood vessels are located, how much fluid or
blood has leaked out, and how healthy the macula is.
•
Photodynamic therapy -- Often used to seal off blood vessels that are under the center of the macula. Using
photocoagulation on that location would result in permanent central vision loss. With photodynamic therapy, the doctor
gives you a drug that stays in the blood vessels under the macula. When a light is shined in your eye, the drug closes them
off without damaging the rest of the macula. Photodynamic therapy slows vision loss but doesn’t stop it.
Progressive Research on
Preventative Treatment
What new research is being done to find treatments for macular
degeneration?
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Researchers continue to explore how macular degeneration might be
promoted by things found in the environment (like cigarette smoke),
inherited genetic differences and diet. Many new treatments are also
being explored, including: drugs to prevent or slow down the progress of
the disease; gene therapies to replace ‘bad’ genes with ‘good’ ones; cells
that can be transplanted into the retina to replace the sick ones; drugs to
prevent the growth of new blood vessels under the macula; computer
chips put in the retina to help simulate vision; and many more.
Case study
“Robert Marcus” a 12 year old with Stargardt’s
Disease.
References
Macular Degeneration International. (n.d.). Understanding macular degeneration. Retrieved from
http://www.maculardegeneration.org/enroll.html
Medline Plus. (2013, April). Macular degeneration. Retrieved from
http://www.nlm.nih.gov/medlineplus/maculardegeneration.html
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MD Support. (2002, October). Types of juvenile macular degeneration. Retrieved from
http://www.mdsupport.org/library/juvenile.html
University of Maryland Medical Center. (2011). Macular degeneration. Retrieved from
http://umm.edu/health/medical/altmed/condition/macular-degeneration
The Children's Corner. (n.d.). Macular degeneration. Retrieved from https://www.childrenscorner.org/aboutmacular-degeneration/quick-facts