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V - W - X - Y - Z
- A
- Achromatopsia
- Rare, inherited vision disorder in which a person has
little or no ability to see color. People with
achromatopsia also commonly experience some vision loss,
especially in bright light, to which they are extremely
sensitive. The severity of achromatopsia varies. Although
there is no cure or treatment for this disorder, people
with achromatopsia can manage its symptoms. For example,
they can wear sunglasses or tinted contact lenses to cope
with bright light. They can use magnifiers and other
devices for
low vision to help them read, and telescopes to help
them see distant objects.
- Suggested resource:
www.achromat.org
- Age-related macular degeneration (ARMD)
- See
macular degeneration.
Suggested resources:
Visual Impairment and Age-Related Macular Degeneration
www.amdalliance.org
www.amd.org
- Albinism
- A hereditary condition characterized by a variable
lack of pigment in the eyes, skin, or hair. People with
albinism may have pale pink skin and blond to white hair,
but there are different types of albinism, and the amount
of pigment varies. The irises of their eyes may be white
or pinkish. They are sensitive to bright light and glare
and commonly have other vision problems. While some people
with albinism can see well enough to drive, many have
impaired vision or may even be legally blind. Tinted
eyeglasses, bifocals, magnifiers, and other optical
devices can help people with this condition. Albinism is
often accompanied by
nystagmus or
strabismus. People with albinism are sensitive to
bright light and glare and may wear tinted eyeglasses.
Bifocals, magnifiers, and other optical devices can help
people with albinism.
- Suggested resource:
www.albinism.org
- Amblyopia
- A condition in which a person's vision does not
develop properly in early childhood because the eye and
the brain are not working together correctly. Amblyopia,
which usually affects only one eye, is also known as "lazy
eye." A person with amblyopia experiences blurred vision
in the affected eye. However, children often do not
complain of blurred vision in the amblyopic eye because
this seems normal to them. Early treatment is advisable,
because if left untreated, this condition may lead to
permanent vision problems or even partial blindness.
Treatment options include vision therapy exercises,
prescription eyeglasses, or surgery. People with amblyopia
may need to wear an eye patch over their stronger eye in
order to force the affected eye to function as it should.
- Suggested resource:
www.preventblindness.org/children/amblyopiaFAQ.html
- Aniridia
- Partial or complete absence of the iris of the eye.
This rare condition, usually present at birth, results in
impaired vision and sensitivity to light. People with
aniridia are also at high risk for certain other eye
conditions, such as
glaucoma,
nystagmus, and
cataracts. People with aniridia may benefit from
wearing tinted contact lenses or sunglasses, using
magnifiers, and avoiding intense or glaring light.
- Suggested resource:
www.aniridia.org
- Anopthalmia
- Rare condition in which one or both eyes do not form
during pregnancy. When both eyes are affected, blindness
results. There is no cure for anopthalmia. Prosthetic eyes
can promote proper growth of the eye sockets and
development of facial bones and also serve cosmetic
purposes.
-
- Suggested resource:
www.kumc.edu/gec/support/anopthal.html
- Aphakia
- Absence of the lens of the eye. Aphakia is usually
associated with the surgical removal of a
cataract but may also result from a wound or other
cause. Without the lens, the eye cannot adjust its focus
for seeing at different distances. Contact lenses or
eyeglasses are used to correct the vision of someone with
aphakia. In cataract surgery, an artificial lens is
inserted to replace the lens removed. A person with
aphakia will benefit from good, but not excessive,
lighting and high-contrast reading materials.
- Suggested resource:
www.tsbvi.edu/Education/anomalies/aphakia.htm
- Astigmatism
- Common vision condition, usually present from birth,
caused by an irregularly curved cornea or lens. People
with astigmatism may experience blurred vision, eyestrain,
or headaches. Two-thirds of Americans who have
myopia also have astigmatism. Astigmatism can be
corrected with eyeglasses or contact lenses. Corrective
surgery is another option.
- Suggested resource:
www.nei.nih.gov/health/cornealdisease/index.asp
Return to the Top
- B
- Best's Disease
- Rare, inherited condition that affects the macula, the
area in the middle of the retina, and can cause blurred or
distorted vision or a loss of central vision. Best's
Disease, also known as Vitelliform Macular Dystrophy,
may affect both eyes. The disease's effects on sight vary
and may not become severe for many years, if ever. Most
people are not significantly affected until after age 40.
There is no treatment for Best's Disease, but a person
whose vision is impaired by this disease may benefit from
devices for
low vision.
- Suggested resource:
www.mdsupport.org/library/pattern_dyst.html
Return to the Top
- C
- Cataract
- A condition in which the lens of the eye, which is
normally clear, becomes cloudy or opaque. Cataracts
generally form slowly and without pain. They can affect
one or both eyes. Over time, a cataract may interfere with
vision, causing images to appear blurred or fuzzy and
colors to seem faded. Most cataracts are related to aging.
In fact, cataracts affect more than 50 percent of all
adults by age 80 and are the primary cause of vision loss
in people 55 and older. People with early cataract may
benefit from new eyeglasses, bright lighting, anti-glare
sunglasses, or magnifying lenses. If, despite such
devices, cataract interferes with daily activities,
surgery is the only effective treatment. Cataract surgery,
which is common, involves removal of the cloudy lens and
replacement with an artificial lens.
- Suggested resources:
Cataracts
www.nei.nih.gov/health/cataract/cataract_facts.asp
- Charles Bonnet syndrome
- Visual disturbances usually occurring in people who
have experienced visual impairment or sight loss later in
life, as through
macular degeneration. People with Charles Bonnet
syndrome may see a wide range of images, from simple
patterns to people, animals, and buildings. The visual
disturbances associated with this syndrome are not signs
of mental illness, and people realize that the images they
are seeing are not real. There is no cure for Charles
Bonnet syndrome. However, the symptoms often stop on their
own. People who have Charles Bonnet syndrome should
consult with an eye care specialist because treatment for
vision disorders may help.
- Suggested resource:
www.mdsupport.org/library/chbonnet.html
- Choroideremia
- Rare disorder that causes progressive loss of the
choroid, an important layer under the retina that is
responsible for some of its blood supply. Choroideremia is
an inherited disorder that generally affects males only.
It commonly begins as night blindness in childhood and
gradually advances to increasing vision loss. Most people
with this disorder are able to retain good vision until
age 40 or 50. There is no treatment for choroideremia, but
people who have the disorder may find it helpful to use
optical, electronic, or computer-based devices for
low vision.
- Suggested resource:
www.choroideremia.org/descriptions/CHMPlain.php
- Coloboma
- A cleft or gap in some part of the eye, such as the
iris, lens, or retina, that is caused by a defect in the
development of the eyeball. How much coloboma affects a
person's vision depends on the size and location of the
cleft and on whether it occurs in one or both eyes. For
example, someone with only a tiny defect in the iris may
have normal vision. However, a person with large defects
in the retina and optic nerve may have limited vision.
Children whose vision is impaired by coloboma may benefit
from using reading materials that have large black print
and well-spaced letters and words. They may also find it
helpful to read one line at a time with the aid of a
cutout reading window.
- Suggested resource:
www.tsbvi.edu/Education/anomalies/coloboma.htm
- Color blindness
- A vision problem in which a person has difficulty
distinguishing certain colors—most commonly red and green,
but sometimes blue and green or blue and yellow. Color
blindness is not really a form of blindness, but rather a
deficiency in color perception. It usually affects both
eyes and is much more common in males than in females.
There is no treatment or cure for this problem, but a
color-blind person can learn to adapt in various ways. For
example, a color-blind driver can remember that the light
positioned at the top of a traffic light is the red one.
It is beneficial to diagnose color blindness in children
at an early age so that steps can be taken to avoid
learning problems related to color perception.
Suggested resource:
www.tsbvi.edu/Education/color.html
- Cone-rod dystrophy
- Inherited disease that, over time, causes
deterioration of the specialized light-sensitive cells of
the retina. People with cone-rod dystrophy typically
experience decreased sharpness of vision followed by a
loss of peripheral vision and color perception. The most
common form of cone-rod dystrophy is
retinitis pigmentosa. There is no treatment or cure
for this disease, which is also referred to as cone-rod
degeneration, progressive cone-rod dystrophy, and retinal
cone dystrophy.
- Suggested resources:
www.mdsupport.org/library/conerod.html
www.icomm.ca/geneinfo/conedyst.htm
- Congenital eye defects
- Any of various conditions present at birth that affect
the eyes or vision. Some congenital eye conditions, such
as
retinitis pigmentosa, are passed on through genes.
Others, such as vision loss due to German measles, result
from a disease or deficiency during pregnancy. Sometimes,
as in the case of
coloboma, the cause of a congenital eye defect is not
known. Congenital eye defects can impair vision or even
cause blindness. Some conditions are immediately apparent
in an infant, while others may not become known until
later in life.
- Corneal disease
- Disease or disorder that affects the cornea, the
clear, curved surface that covers the front of the eye.
The effects of corneal disease vary. Some corneal
conditions cause few, if any, vision problems. For
example, infections of the cornea can often be treated
with antibiotics. However, if the cornea becomes cloudy,
light cannot penetrate the eye to reach the retina, and
severe visual impairment, or even blindness, may result.
Corneal dystrophies are usually inherited conditions in
which one or more parts of the cornea lose their clarity
due to a buildup of cloudy material.
Keratoconus is the most common corneal dystrophy in
the United States. When corneal disease causes the cornea
to become permanently clouded or scarred, doctors may be
able to restore vision with a corneal transplant—surgical
replacement of the old cornea with a new one.
Suggested resource:
http://www.nei.nih.gov/health/cornealdisease/index.asp
- Cortical visual impairment
- Visual impairment caused by damage to the part of the
brain related to vision. Although the eye is normal, the
brain cannot properly process the information it receives.
The degree of vision loss may be mild or severe and can
vary greatly, even from day to day. Cortical visual
impairment may be temporary or permanent. People with
cortical visual impairment have difficulty using what
their eye sees. For example, they may have trouble
recognizing faces, interpreting drawings, perceiving
depth, or distinguishing between background and
foreground. Children with cortical visual impairment are
often able to see better when told in advance what to look
for. Cortical visual impairment is also known as
neurological visual impairment (NVI).
- Suggested resources:
www.aph.org/cvi
www.blindbabies.org/factsheet_cvi.htm
Return to the Top
- D
- DeMorsier's Syndrome
- Rare disorder, present at birth, in which the optic
nerve is underdeveloped, the pituitary gland does not
function properly, and often a portion of brain tissue is
not formed. De Morsier's Syndrome, also known as septo-optic
dysplasia, may cause blindness in one or both eyes and is
also often accompanied by
nystagmus and various other symptoms. Some children
with De Morsier's Syndrome have normal intelligence, while
others may be developmentally delayed, learning-disabled,
or mentally retarded. Some symptoms of this disorder can
be treated, but the visual impairment usually cannot be
corrected. Visual devices, such as a magnifier or a
computer designed for visually impaired users, may benefit
some people with De Morsier's Syndrome.
- Diabetic retinopathy
- Eye condition that results from the damaging effect of
diabetes on the circulatory system of the retina. The
longer someone has had diabetes, the greater the person's
likelihood of developing diabetic retinopathy. Changes in
the tiny blood vessels of the retina can lead to vision
loss. People with diabetes should have routine eye
examinations so that diabetes-related problems can be
diagnosed and treated as soon as possible. Maintaining
strict control of blood sugar levels helps to prevent
diabetic retinopathy. Surgical and laser treatments can
help many people affected with this condition.
- Suggested resources:
Visual Impairment and Diabetic Retinopathy
www.nei.nih.gov/health/diabetic/retinopathy.asp
- Dry eye syndrome
- Persistent dryness of the eyes resulting from too
little production of tears or too rapid evaporation of
tears. People with dry eye syndrome may experience such
symptoms as itching, burning, or stinging eyes. Some
people feel as though something is caught in their eye,
causing an irritation. Dry eye syndrome has many causes.
For example, it may be linked to wearing contact lenses
for long periods of time or to living in a dry or dusty
climate. It may be a side effect of medication or a
symptom of certain diseases. An eye doctor may recommend
the application of special eye drops—"artificial tears"—to
moisten the eyes or the use of a humidifier to increase
humidity in the air. Not rubbing the eyes and avoiding
such irritants as tobacco smoke can also help persons with
dry eye syndrome. There is also now medication to treat
moderate to severe dry eye.
- Suggested resource:
www.dryeye.org/patients.htm
Return to the Top
- F
- Floaters and spots
- Specks or strands that seem to float across the field
of vision. Floaters and spots are actually shadows on the
retina cast by tiny bits of gel or cells inside the clear
fluid that fills the eye. Floaters and spots usually are
normal and harmless. However, in some cases they may warn
of serious conditions such as
retinal detachment,
diabetic retinopathy, or infection. Someone who
experiences a sudden decline in vision accompanied by
flashes and floaters or a sudden increase in the number of
floaters should consult an ophthalmologist urgently.
Floaters and spots generally do not require treatment. In
those rare instances when they significantly impair
vision, surgery may be an option.
- Suggested resources:
www.sa.psu.edu/uhs/healthinformation/patientlibrary/health/spots.cfm
www.aoa.org/eweb/DynamicPage.aspx?site=AOAstage&WebCode=SpotsFloaters
Return to the Top
- G
- Glaucoma
- Disease in which the pressure of the fluid inside the
eye is too high, resulting in a loss of peripheral vision.
If the condition is not diagnosed and treated, the
increased pressure can damage the optic nerve and
eventually lead to total blindness. Vision lost as a
result of such damage cannot be restored. A person who has
glaucoma may not realize it at first, because the disease
often progresses with no symptoms or warning signs. Early
detection through regular eye examination and prompt
treatment is essential to prevent vision loss. Daily
medication (usually eye drops), surgery, or a combination
of both enables most people to control their intraocular
pressure and retain their vision.
- Suggested resources:
Visual Impairment and Glaucoma
www.glaucoma.org
Return to the Top
- H
- Hemianopia
- Blindness affecting half of the field of vision.
Hemianopia, also known as hemianopsia, may be caused by
various medical conditions, but usually results from a
stroke or brain injury. It may affect either the right or
left side of the visual field and is usually permanent.
Hemianopia can produce various effects, from minor to
severe. For example, a person may be able to see only to
one side when looking ahead, or objects that the person
sees may differ in clarity or brightness. Such visual
impairment can make it difficult to perform daily tasks,
from reading to crossing streets. There is no specific
treatment for hemianopia, but
low vision rehabilitation specialists can help people
learn to make the most of the sight that they have. In
addition, some people with hemianopia benefit from the use
of magnifiers or special prism lenses.
- Suggested resources:
www.lowvision.org/new_page_1hemi.htm
www.csbps.com/publicinfo/strokes.shtml
- Hyperopia
- This common vision problem, also known as
farsightedness, occurs when light rays entering the eye
focus behind the retina, not directly on it. People with
hyperopia are usually able to see distant objects well,
but close objects appear blurry. Hyperopia may cause
eyestrain or headaches, especially with reading.
Eyeglasses or contact lenses can correct hyperopia. For
people who do not want to wear glasses or contact lenses,
laser vision correction is sometimes possible.
- Suggested resource:
www.aoa.org/eweb/DynamicPage.aspx?site=AOAstage&WebCode=Hyperopia
Return to the Top
- K
- Keratoconus
- Rare condition, often inherited, in which the cornea
becomes progressively thinner and gradually bulges
outward, causing blurred or distorted vision. Keratoconus
usually affects both eyes. At first, people with this
condition can correct their sight with eyeglasses.
However, as symptoms worsen over time, specially designed
contact lenses are needed to improve vision. Most people
with keratoconus will not experience severe visual
impairment. However, as many as one in five will
eventually require a corneal transplant (surgical
replacement of the old cornea with a new one).
Suggested resource:
www.nkcf.org
Return to the Top
- L
- Laurence-Moon-Bardet-Biedl Syndrome
- Rare, inherited disorder affecting many parts of the
body. People with this condition have
retinitis pigmentosa accompanied by mental
retardation, paralysis of the legs, and various other
symptoms.
Suggested resource:
www.familyvillage.wisc.edu/lib_lmbb.htm
- Leber's congenital amaurosis
- Inherited condition, probably caused by degeneration
of the retina, in which an infant is born blind or
develops severe vision loss soon after birth. Children
with Leber's congenital amaurosis typically also have
nystagmus, and some also have mental retardation and
hearing disorders. At present, there is no treatment for
this condition.
- Suggested resource:
www.icomm.ca/geneinfo/lebersam.htm
- Legal blindness
- A level of visual impairment that has been defined by
law to determine eligibility for benefits. It refers to
central visual acuity of 20/200 or less in the better eye
with the best possible correction, as measured on a
Snellen vision chart, or a visual field of 20 degrees or
less.
- Low vision
- Vision loss that may be severe enough to impede a
person's ability to carry on everyday activities, but
still allows some functionally useful sight. Low vision
may be caused by
macular degeneration,
cataracts,
glaucoma, or other eye conditions or diseases. Low
vision may range from moderate impairment to near-total
blindness. It cannot be fully corrected by eyeglasses,
contact lenses, or surgery. However, a person with low
vision may benefit from any of a variety of available
optical devices, such as electronic magnifying glasses or
eyeglass-mounted telescopes. In addition, special software
developed for computer users with low vision can display
type in large size or read text aloud.
- Suggested resource:
www.lowvision.org
Return to the Top
- M
- Macular degeneration
- Disease that causes dysfunction of the macula, the
area in the middle of the retina that makes possible the
sharp central vision needed for such everyday activities
as reading, driving, and recognizing faces and colors. The
condition is commonly known as age-related macular
degeneration (ARMD) and is the leading cause of visual
impairment among older people. However, there are also
other types of macular degeneration, such as
Stargardt's Disease and
Best's Disease. Macular degeneration causes blurred,
distorted, or dim vision or a blind spot in the center of
the visual field. Peripheral vision is generally not
affected. This condition is painless and may progress so
gradually that the affected person at first notices little
change. There is no cure for macular degeneration, but
drug therapy, laser surgery, or other medical treatment
may in some cases be able to slow the disease's
progression or prevent further vision loss. People with
macular degeneration can also benefit from the use of
various devices for
low vision, such as magnifiers, high-intensity lamps,
and pocket-sized telescopes.
- Suggested resources:
www.macular-degeneration.org
www.amd.org
www.blindness.org/macular-degeneration.asp
- Marfan Syndrome
- Disorder of the connective tissue, affecting the heart
and blood vessels, skeletal system, eyes, and other parts
of the body. The condition is present at birth. Symptoms
vary from person to person, ranging from mild to severe.
People with Marfan syndrome are often nearsighted (see
myopia), and about half have dislocation of one or
both lenses of the eye. There is no cure for Marfan
syndrome. Treatment depends on which body systems are
affected. Early eye examinations can detect vision
problems related to the disorder, which can usually be
corrected with eyeglasses or contact lenses.
- Suggested resource:
www.marfan.org
- Microphthalmia
- Rare disorder, usually inherited, in which one or both
eyes are abnormally small. The degree of visual impairment
varies, from reduced vision to blindness. Extreme
microphthalmia resembles some forms of
anopthalmia. There is no treatment or cure for
micropthalmia. In certain cases, artificial eyes can be
used to promote proper growth of the eye sockets and to
help with cosmetic appearance.
- Myopia
- This condition, commonly known as nearsightedness,
occurs when light rays entering the eye focus in front of
the retina, not directly on it. People with myopia are
usually able to see close objects well, but objects in the
distance—such as highway signs or writing on a
chalkboard—appear blurred. People with this condition may
squint to see distant objects and experience eyestrain or,
sometimes, headaches. Eyeglasses or contact lenses can
correct myopia. Surgery is another alternative.
- Suggested resource:
www.aoa.org/eweb/DynamicPage.aspx?site=AOAstage&WebCode=Myopia
Return to the Top
- N
- Neurological visual impairment (NVI)
- See
cortical visual impairment.
Suggested resource:
www.sfsu.edu/~cadbs/Eng022.html
- Nystagmus
- Condition that involves involuntary, rapid, repetitive
movements of one or both eyes from side to side, up and
down, or in a circular motion. Nystagmus may be present at
birth or, less commonly, may result from disease or
injury. In some cases, the condition can reduce or
interfere with vision. For example, children with
nystagmus may frequently lose their place when reading.
Placing a cutout reading window over words or using a card
to "underline" text can be helpful.
Suggested resource:
www.nystagmus.org
Return to the Top
- O
- Optic nerve atrophy
- Degeneration of the optic nerve, which carries vision
information from the eye to the brain. People who have
optic nerve atrophy may have dimmed or blurred vision as
well as a reduced field of vision. They may also have
difficulty seeing contrast and fine detail. Vision loss
through optic nerve atrophy is permanent. However, if the
underlying cause can be identified and successfully
treated, further vision loss may be prevented. Bright
lighting, high contrast, and bold colors can help children
with optic nerve atrophy see more clearly.
Suggested resource:
www.blindbabies.org/factsheet_ona.htm
- Optic nerve hypoplasia
- Condition, present at birth, in which the optic nerve
is underdeveloped, so that adequate visual information is
not carried from the eye to the brain. The effects of
optic nerve hypoplasia have a broad range, from little or
no visual impairment to near-total blindness. The
condition may affect one or both eyes. There is no
treatment or cure for optic nerve hypoplasia. However,
depending on the degree of visual impairment, a person
with this condition may benefit from the use of devices
for
low vision.
- Suggested resource:
www.blindbabies.org/factsheet_onh.htm
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- P
- Presbyopia
- The eye's gradually decreasing ability to focus on
nearby objects. Presbyopia is a normal part of aging and
affects virtually everyone, usually becoming noticeable
after age 40. People with presbyopia typically hold
reading materials at arm's length in order to bring the
words into focus. They may experience headaches or
eyestrain while reading, viewing a computer screen, or
doing close work. Presbyopia can be corrected with reading
glasses, bifocal or variable focus lenses, or contact
lenses. Using bright, direct light when reading is also
helpful.
- Suggested resources:
www.aoa.org/eweb/DynamicPage.aspx?site=AOAstage&WebCode=Presbyopia
www.agingeye.net/otheragingeye/presbyopia.php
Return to the Top
- R
- Retinal detachment
- Separation of the retina from the underlying
supportive tissues. Retinal detachment may result from
injury, disease, or other causes. This condition occurs
most often in middle-aged and elderly people. A person
with retinal detachment usually does not experience pain,
but may see floaters (see
floaters and spots) or bright flashes of light, may
have blurred vision, or may see a shadow or curtain over
part of the field of vision. Retinal detachment requires
prompt medical attention to prevent permanent vision loss.
There are several methods of treatment for retinal
detachment, including laser surgery.
- Suggested resource:
www.nei.nih.gov/health/retinaldetach/index.asp
- Retinitis pigmentosa
- Degeneration of the retina, resulting in decreased
night vision, a gradual loss of peripheral vision, and in
some cases, loss of central vision. The degeneration
progresses over time and can lead to total blindness.
Retinitis pigmentosa is a rare, inherited disease for
which there is as yet no treatment or cure. Some
opthalmologists believe that treatment with high doses of
Vitamin A can slow the progression of retinitis pigmentosa,
and that taking Vitamin E makes it worse. Early diagnosis
enables a person with the disease to plan and prepare for
its progression. In addition, depending on the degree of
vision loss, electronic magnifiers, night-vision scopes,
and other such special devices for impaired vision can
provide some benefit for people with the disease.
- Suggested resources:
www.preventblindness.org/eye_problems/rpFAQ.html
www.blindness.org/retinitis-pigmentosa.asp
- Retinoblastoma
- Malignant tumor (cancer) of the retina, generally
affecting children under the age of 6. Usually hereditary,
retinoblastoma may affect one or both eyes. Retinoblastoma
has a cure rate of over 90 percent if treated early.
Without prompt reatment, the cancer can spread to the eye
socket, the brain, and elsewhere, and can cause death.
Depending on the size and location of the tumor, treatment
options include laser surgery, cryotherapy (a freezing
treatment), radiation, and chemotherapy. In some cases,
the affected eye may need to be removed.
Suggested resource:
www.instituteforfamilies.org/retinoblastoma.html
- Retinopathy of prematurity (ROP)
- Condition associated with premature birth, in which
the growth of normal blood vessels in the retina stops,
and abnormal blood vessels develop. As a result, the
infant has an increased risk of detachment of the retina
(see
retinal detachment). Retinopathy of prematurity can
lead to reduced vision or blindness. Laser therapy can
help this condition if diagnosis and treatment occur
early. Children who experience minor effects may benefit
from the use of devices for
low vision as they get older. Retinopathy of
prematurity was formerly called retrolental fibroplasia.
- Suggested resources:
www.ropard.org
http://www.nei.nih.gov/health/rop/index.asp
- Retrolental fibroplasia
- See
retinopathy of prematurity.
- Rod-cone dystrophy
- See
Cone-rod dystrophy.
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- S
- Scotoma
- Gap or blind spot in the field of vision that may
result from damage to the retina. How much a scotoma
impairs sight depends mainly on whether it affects central
or peripheral vision. Common causes of scotoma include
macular degeneration,
glaucoma, and inflammation of the optic nerve. People
who experience significant vision loss because of scotomas
may benefit from the use of magnifiers, bright lighting,
and large-print reading materials.
Suggested resource:
www.tsbvi.edu/Education/anomalies/scotoma.htm
- Septo-Optic Dysplasia (SOD)
- See
DeMorsier's Syndrome.
Suggested resources:
www.focusfamilies.org/focus/usdefault.asp
www.ninds.nih.gov/health_and_medical/disorders/septo-optic.htm
- Stargardt's Disease
- Inherited disease that causes gradual degeneration of
the macula, the area in the middle of the retina that
makes possible the central vision needed for reading,
driving, recognizing colors, and other activities of daily
life. Effects of Stargardt's Disease, which start at an
early age, vary from minor to total loss of detail vision.
Over a period of years, people with the disease typically
lose sharpness of vision, experience decreased color
vision, and may have blind spots. However, peripheral and
night vision usually remain unaffected, and complete loss
of sight is rare. There is no cure or treatment for
Stargardt's Disease, but such devices as magnifying
screens and binocular lenses can help people cope with
vision limitations.
Suggested resources:
www.blindness.org/stargardt-disease.asp
www.mdsupport.org/library/stargrdt.html
- Strabismus
- Condition in which the eyes are not both directed
toward the same point simultaneously. Strabismus occurs
when eye muscles are not working together properly. It is
most commonly an inherited condition, but may also be
caused by disease or injury. If diagnosed early,
strabismus can usually be corrected. The condition may be
treated with corrective eyeglasses, eye-muscle exercises,
surgery, or a combination of these approaches. Young
children with this condition may need to wear an eye patch
over their stronger eye to force their weaker eye to
function correctly. Children whose strabismus is not
corrected may develop
amblyopia.
- Suggested resource:
www.cnib.ca/eng/eye_con/cospubs/strabsms.htm
- Sturge-Weber Syndrome
- Disorder, present at birth, characterized by a facial
birthmark and any of various neurological, visual, and
developmental symptoms. People with Sturge-Weber syndrome
may, for example, experience seizures,
glaucoma, partial paralysis, and learning
disabilities. There is no cure for Sturge-Weber syndrome,
but many of the symptoms can be treated. For instance,
medications may be prescribed to control seizures, and
surgery or eye drops may be used to treat glaucoma.
Return to the Top
- T
- Trachoma
- Contagious eye infection, caused by bacteria, that
affects the eyelid and cornea. Trachoma can lead to
scarring and blindness if not treated. The infection is
spread by contact with discharge from the eyes or nose of
infected persons and also transmitted by certain flies.
Trachoma is rare in the United States, but it affects
millions of people around the world, many of them
children. Antibiotics are generally an effective treatment
for trachoma, especially if used early in the infection.
In certain cases, eyelid surgery may be needed.
- Suggested resource:
www.trachoma.org/home.asp
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- U
- Usher Syndrome
- Inherited condition that causes partial or total
hearing loss accompanied by gradual vision loss resulting
from
retinitis pigmentosa. Some people with Usher Syndrome
also have problems with balance. There is no cure for the
condition. However, early diagnosis makes it possible to
help people with Usher Syndrome by providing hearing aids,
training in sign language and lip reading, devices for
impaired vision, and counseling for preparing for the
future.
- Suggested resources:
www.blindness.org/usher-syndrome.asp
www.icomm.ca/geneinfo/usher.htm
- Uveitis
- Inflammation inside the eye, affecting the structures
that provide most of the blood supply to the retina.
Uveitis may affect one or both eyes. The condition may be
associated with an underlying disease or have other
causes, but in many cases it affects people who are
otherwise healthy. People with uveitis typically
experience redness of the eye, blurred vision, and light
sensitivity. They may also feel pain and see floaters (see
floaters and spots). If not properly treated, uveitis
can lead to scarring and vision loss. Treatment depends on
which eye structures are affected and whether there is an
underlying disease. Eye drops and other medications are
commonly prescribed to reduce inflammation.
- Suggested resource:
www.uveitis.org
- V
- Vitelliform Macular Dystrophy
- See
Best's Disease.
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