Conditions

Stargardt Disease

Stargardt disease is the most common form of inherited juvenile macular degeneration. The progressive vision loss associated with Stargardt disease is caused by the death of photoreceptor cells in the central portion of the retina called the macula.

The retina is the delicate light-sensing tissue lining the back inside wall of the eye. Photoreceptor cells in the retina provide vision by conveying information from the visual field to the brain. The macula is responsible for sharp central vision for tasks like reading, watching television, and looking at faces.

Decreased central vision is a hallmark of Stargardt disease. Side vision is usually preserved. Stargardt disease typically develops during childhood and adolescence. Also involved in Stargardt disease is a region beneath the macula called the retinal pigment epithelium.

What are the symptoms?

The symptom that brings most people to an eye doctor is a change in central vision. A doctor looking at the retina of a person with Stargardt disease will see characteristic yellowish flecks in and under the macula. The flecks might extend outward in a ring-like fashion.

The flecks are deposits of lipofuscin, a fatty byproduct of normal cell activity. In Stargardt disease, lipofuscin accumulates abnormally. The Foundation Fighting Blindness supports research studying lipofuscin build up and ways to prevent it.

A decrease in color perception also occurs in Stargardt disease. This is because photoreceptor cells involved in color perception are concentrated in the macula.

How quickly does vision fade?

The progression of symptoms in Stargardt disease is variable. Visual acuity (the ability to distinguish details and shape) may decrease slowly at first, accelerate, and then level off.

A study of 95 people with Stargardt disease showed that once a visual acuity of 20/40 is reached, there is often rapid progression of additional vision loss until it reaches 20/200. (Normal vision is 20/20. A person with 20/40 vision sees at 20 feet what someone with normal vision sees at 40 feet.) By age 50, approximately 50 percent of people in the study had visual acuities of 20/200 or worse.

Eventually, almost everyone with Stargardt disease has a visual acuity in the range of 20/200 to 20/400. The vision loss is not correctable with prescription eyeglasses, contact lenses, or refractive surgery.

Is it an inherited disease?

Stargardt disease is almost always inherited as an autosomal recessive trait. It is inherited when both parents, called carriers, have one gene for the disease paired with one normal gene. Each child has a 25 percent chance of inheriting the two copies of the Stargardt gene (one from each parent) needed to cause the disease. Carrier parents are unaffected because they have only one copy of the gene.

In 1997, Foundation-funded researchers found the gene for Stargardt disease, ABCA4, which normally causes the production of a protein involved in the visual cycle. Lipofuscin buildup appears to be related to a mutation in this gene, and the resulting production of a dysfunctional protein.

Genetic counselors are an excellent resource for discussing inheritability, family planning, career choices and other issues related to living with Stargardt disease.

What treatment is available?

While there are currently no treatments for Stargardt disease, the Foundation is supporting several promising avenues of research, including gene, stem cell and drug therapies.

For the latest research advances for Stargardt disease treatments, refer to the Foundation publication Stargardt Disease: Research Advances (opens in new tab/window).

UV blocking sunglasses are generally recommended for outdoors. For people who already have significant vision loss, low vision aides are available.

Are there any related diseases?

Stargardt disease is also known as Stargardt macular dystrophy or fundus flavimaculatus. In addition to recessive Stargardt disease, there are other rarer forms inherited as dominant rather than recessive traits.

For further info visit http://www.blindness.org/stargardt-disease

Macular Degeneration

Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye’s macula. The macula is a small area in the retina the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly.

The macula makes up only a small part of the retina, yet it is much more sensitive to detail than the rest of the retina (called the peripheral retina). The macula is what allows you to thread a needle, read small print, and read street signs. The peripheral retina gives you side (or peripheral) vision. If someone is standing off to one side of your vision, your peripheral retina helps you know that person is there by allowing you to see their general shape.

Many older people develop macular degeneration as part of the body’s natural aging process. There are different kinds of macular problems, but the most common is age-related macular degeneration.

With macular degeneration, you may have symptoms such as blurriness, dark areas or distortion in your central vision, and perhaps permanent loss of your central vision. It usually does not affect your side, or peripheral vision. For example, with advanced macular degeneration, you could see the outline of a clock, yet may not be able to see the hands of the clock to tell what time it is.

Causes of macular degeneration include the formation of deposits called drusen under the retina, and in some cases, the growth of abnormal blood vessels under the retina. With or without treatment, macular degeneration alone almost never causes total blindness. People with more advanced cases of macular degeneration continue to have useful vision using their side, or peripheral vision. In many cases, macular degeneration’s impact on your vision can be minimal.

When macular degeneration does lead to loss of vision, it usually begins in just one eye, though it may affect the other eye later.

Many people are not aware that they have macular degeneration until they have a noticeable vision problem or until it is detected during an eye examination.

There are two types of macular degeneration:

Dry, or atrophic, macular degeneration (also called non-neovascular macular degeneration) with drusen

Most people who have macular degeneration have the dry form. This condition is caused by aging and thinning of the tissues of the macula. Macular degeneration usually begins when tiny yellow or white pieces of fatty protein called drusen form under the retina. Eventually, the macula may become thinner and stop working properly.

With dry macular degeneration, vision loss is usually gradual. People who develop dry macular degeneration must carefully and constantly monitor their central vision. If you notice any changes in your vision, you should tell your ophthalmologist right away, as the dry form can change into the more damaging form of macular degeneration called wet (exudative) macular degeneration. While there is no medication or treatment for dry macular degeneration, some people may benefit from a vitamin therapy regimen for dry macular degeneration.

For more information visit http://www.aao.org/eye-health/diseases/amd-macular-degeneration

Glaucoma

Glaucoma is a group of eye diseases that gradually steal sight without warning. In the early stages of the disease, there may be no symptoms. Experts estimate that half of the people affected by glaucoma may not know they have it.

Vision loss is caused by damage to the optic nerve. This nerve acts like an electric cable with over a million wires. It is responsible for carrying images from the eye to the brain.

There is no cure for glaucoma­yet. However, medication or surgery can slow or prevent further vision loss. The appropriate treatment depends upon the type of glaucoma among other factors. Early detection is vital to stopping the progress of the disease.

It was once thought that high pressure within the eye, also known as intraocular pressure or IOP, is the main cause of this optic nerve damage. Although IOP is clearly a risk factor, we now know that other factors must also be involved because even people with “normal” levels of pressure can experience vision loss from glaucoma.

The most common type of glaucoma is open-angle glaucoma.

The other main type of adult glaucoma is angle-closure glaucoma.

For more information visit http://www.glaucoma.org/glaucoma/what-is-glaucoma.php

Retinitis Pigmentosa(RP)

What is Retinitis Pigmentosa?

Retinitis Pigmentosa (RP) is the name given to a group of degenerative diseases
of the retina. The retina, at the back of the eye, is a thin sheet of interconnected
nerve cells including the light sensitive cells (rods). It is here that light
is converted into electrical signals to the brain where "seeing" takes
place.
In RP the rod and cone cells degenerate. Depending on the type of RP, the rate
of progression varies.

What are the symptoms?

Usually the rod cells are the first to be affected. They are concentrated away
from the centre of vision in the retina and are responsible for seeing in dim
light. Thus, one of the earliest symptoms is often night blindness followed
by loss of peripheral vision leading to "tunnel vision". Cone cells
in contrast are concentrated in the centre of the retina and are responsible
for brightly detailed colour vision. In cases where the cone cells degenerate
first, central vision becomes blurred and loss of colour perception occurs.
Peripheral vision is initially retained. Although the majority of people with
RP do not suffer from associated disabilities, it does happen. Deafness associated
with RP in a condition known as Usher syndrome is one such disability.

Who does it affect?

The symptoms of RP may occur at any age but most commonly they appear in young
adults. Generally speaking, the earlier the disease begins, the more severe
the symptoms. Occasionally the disease is present at birth and can be diagnosed
with appropriate testing at that time. RP is recognized as one of the most common
inherited causes of blindness in people between the ages of 20 and 60.

How quickly does it progress?

Most patients have very gradual progression of symptoms, often over many years
or decades. Generally, when other members of a family are affected, the rate
of vision loss is usually similar. Different forms of RP advance at different
rates.

Can the progress be halted and is there a cure?

To date, there is no known way to halt the degeneration of the retina or cure
the disease. Transplants of the retina are not possible at this time and there
is no convincing scientific evidence to demonstrate benefit from any treatment
methods currently available. There are, however, a number of areas currently
being researched that demonstrate great potential.

How is it diagnosed?

Whenever RP is suspected or is a concern, a person should be evaluated by an
ophthalmologist (medical eye doctor). The disease is usually most difficult
to diagnose in the earliest stages. Depending on the stage and type of the disorder,
tests of vision function such as visual field, dark adaptation and electroretinograms
(ERG) are made to determine the precise state of the retina.

How is it transmitted?

Fifty per cent of cases of RP are sporadic with no previous family history.
The cause of these cases cannot be explained. Other cases are inherited and
fall into three main groups:

Autosomal recessive forms of the disease occur when both parents are unaffected
carriers of the same defective gene. The chance of a child of theirs being affected
is 1 in 4 (the affected child must inherit the defective gene from each parent).
The chances of a parent having an unaffected child who, like them, would be
a carrier of the defective gene are 1 in 2. The chance of such parents having
a child completely free of the RP gene is 1 in 4.

Autosomal dominant forms of the disease are characterized by expression of
the disease in either males or females when only a single copy of the gene is
defective. In such cases, it is typical that one of the parents is affected
by the disease. Since the affected parent has one normal and one defective gene,
the chance is 1 in 2 of any given offspring being affected by the disease.

X-linked (or sex linked) recessive forms occur in offspring in two ways. The
fathers can be affected or mothers can be carriers of the defective gene. If
the father is affected, all sons will be unaffected and all daughters will be
carriers. If the mother is the carrier, 1 in 2 sons will be affected and 1 in
2 daughters will be carriers.

How is the type determined?

Family history is the single most important factor to determine the type of
RP. Family members should be examined by an ophthalmologist. For example, some
female carriers of the X-linked form can be identified by slight pigmentary
change or a golden reflex in the retina.

What action can be taken by those affected?

Those affected by RP should seek the best information available from ophthalmologists
about their particular condition. Depending on the condition, further action
may be appropriate in the field of education, training and family planning.

Back toFAQ’s list


My Condition.

What is Retinitis Pigmentosa?

Retinitis Pigmentosa (RP) is the name given to a group of degenerative diseases
of the retina. The retina, at the back of the eye, is a thin sheet of interconnected
nerve cells including the light sensitive cells (rods). It is here that light
is converted into electrical signals to the brain where "seeing" takes
place.
In RP the rod and cone cells degenerate. Depending on the type of RP, the rate
of progression varies.

What are the symptoms?

Usually the rod cells are the first to be affected. They are concentrated away
from the centre of vision in the retina and are responsible for seeing in dim
light. Thus, one of the earliest symptoms is often night blindness followed
by loss of peripheral vision leading to "tunnel vision". Cone cells
in contrast are concentrated in the centre of the retina and are responsible
for brightly detailed colour vision. In cases where the cone cells degenerate
first, central vision becomes blurred and loss of colour perception occurs.
Peripheral vision is initially retained. Although the majority of people with
RP do not suffer from associated disabilities, it does happen. Deafness associated
with RP in a condition known as Usher syndrome is one such disability.

Who does it affect?

The symptoms of RP may occur at any age but most commonly they appear in young
adults. Generally speaking, the earlier the disease begins, the more severe
the symptoms. Occasionally the disease is present at birth and can be diagnosed
with appropriate testing at that time. RP is recognized as one of the most common
inherited causes of blindness in people between the ages of 20 and 60.

How quickly does it progress?

Most patients have very gradual progression of symptoms, often over many years
or decades. Generally, when other members of a family are affected, the rate
of vision loss is usually similar. Different forms of RP advance at different
rates.

Can the progress be halted and is there a cure?

To date, there is no known way to halt the degeneration of the retina or cure
the disease. Transplants of the retina are not possible at this time and there
is no convincing scientific evidence to demonstrate benefit from any treatment
methods currently available. There are, however, a number of areas currently
being researched that demonstrate great potential.

How is it diagnosed?

Whenever RP is suspected or is a concern, a person should be evaluated by an
ophthalmologist (medical eye doctor). The disease is usually most difficult
to diagnose in the earliest stages. Depending on the stage and type of the disorder,
tests of vision function such as visual field, dark adaptation and electroretinograms
(ERG) are made to determine the precise state of the retina.

How is it transmitted?

Fifty per cent of cases of RP are sporadic with no previous family history.
The cause of these cases cannot be explained. Other cases are inherited and
fall into three main groups:

Autosomal recessive forms of the disease occur when both parents are unaffected
carriers of the same defective gene. The chance of a child of theirs being affected
is 1 in 4 (the affected child must inherit the defective gene from each parent).
The chances of a parent having an unaffected child who, like them, would be
a carrier of the defective gene are 1 in 2. The chance of such parents having
a child completely free of the RP gene is 1 in 4.

Autosomal dominant forms of the disease are characterized by expression of
the disease in either males or females when only a single copy of the gene is
defective. In such cases, it is typical that one of the parents is affected
by the disease. Since the affected parent has one normal and one defective gene,
the chance is 1 in 2 of any given offspring being affected by the disease.

X-linked (or sex linked) recessive forms occur in offspring in two ways. The
fathers can be affected or mothers can be carriers of the defective gene. If
the father is affected, all sons will be unaffected and all daughters will be
carriers. If the mother is the carrier, 1 in 2 sons will be affected and 1 in
2 daughters will be carriers.

How is the type determined?

Family history is the single most important factor to determine the type of
RP. Family members should be examined by an ophthalmologist. For example, some
female carriers of the X-linked form can be identified by slight pigmentary
change or a golden reflex in the retina.

What action can be taken by those affected?

Those affected by RP should seek the best information available from ophthalmologists
about their particular condition. Depending on the condition, further action
may be appropriate in the field of education, training and family planning.