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$Unique_ID{BRK03627}
$Pretitle{}
$Title{Corneal Dystrophy}
$Subject{Corneal Dystrophy Cornea Dystrophy Endothelial Corneal Dystrophy,
Congenital (Congenital Hereditary Corneal Dystrophy; Maumenee Corneal
Dystrophy) Crystalline Corneal Dystrophy of Schnyder Endothelial Epithelial
Corneal Dystrophy (Fuchs Dystrophy) Epithelial Basement Membrane Corneal
Dystrophy (Cogan Corneal Dystrophy; Map-Dot-Fingerprint Type Corneal
Dystrophy; Microcystic Corneal Dystrophy; Anterior Membrane Corneal Dystrophy)
Epithelial Corneal Dystrophy of Meesmann, Juvenile Francois-Neetens Speckled
or Flecked Corneal Dystrophy Granular Type Corneal Dystrophy (Groenouw Type I
Corneal Dystrophy) Lattice Corneal Dystrophy (Biber-Haab-Dimmer Corneal
Dystrophy) Lipoid Corneal Dystrophy Macular Type Corneal Dystrophy (Groenouw
Type II Corneal Dystrophy) Marginal Corneal Dystrophy (Terrien Corneal
Dystrophy) Polymorphous (Posterior) Corneal Dystrophy, Hereditary
Reis-Bucklers Corneal Dystrophy Salzmann Nodular Corneal Dystrophy (Nodular
Cornea Degeneration) Stromal Corneal Dystrophy Recurrent Cornea Erosion}
$Volume{}
$Log{}

Copyright (C) 1988, 1989 National Organization for Rare Disorders, Inc.

455:
Corneal Dystrophy

** IMPORTANT **
It is possible the main title of the article (Corneal Dystrophy) is not
the name you expected.  Please check the SYNONYMS listing on the next page to
find alternate names, disorder subdivisions, and related disorders covered by
this article.

Synonyms

     Cornea Dystrophy

There are many different types of Corneal Dystrophy.  This report contains
information on the following specific Corneal Dystrophies:

     Endothelial Corneal Dystrophy, Congenital (Congenital Hereditary Corneal
Dystrophy; Maumenee Corneal Dystrophy)

     Crystalline Corneal Dystrophy of Schnyder

     Endothelial Epithelial Corneal Dystrophy (Fuchs Dystrophy)

     Epithelial Basement Membrane Corneal Dystrophy (Cogan Corneal Dystrophy;
Map-Dot-Fingerprint Type Corneal Dystrophy; Microcystic Corneal Dystrophy;
Anterior Membrane Corneal Dystrophy)

     Epithelial Corneal Dystrophy of Meesmann, Juvenile

     Francois-Neetens Speckled or Flecked Corneal Dystrophy

     Granular Type Corneal Dystrophy (Groenouw Type I Corneal Dystrophy)

     Lattice Corneal Dystrophy (Biber-Haab-Dimmer Corneal Dystrophy)

     Lipoid Corneal Dystrophy

     Macular Type Corneal Dystrophy (Groenouw Type II Corneal Dystrophy)

     Marginal Corneal Dystrophy (Terrien Corneal Dystrophy)

     Polymorphous (Posterior) Corneal Dystrophy, Hereditary

     Reis-Bucklers Corneal Dystrophy

     Salzmann Nodular Corneal Dystrophy (Nodular Cornea Degeneration)

     Stromal Corneal Dystrophy

Information on the following disease may be found in the Related
Disorders section of this report:

Recurrent Cornea Erosion

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.

Corneal Dystrophies are disorders affecting the outer clear layer of the
eyeball known as the cornea.  They are caused by faulty metabolism in the
tissues in and around the eye.  Clarity of vision is usually impaired by
clouding of the cornea.

Symptoms

The main symptom of Corneal Dystrophy is usually vision impairment.  Eye
irritation may also occur.  The cornea consists of five layers, from the
outside inward they are epithelium, Bowman membrane, stroma, Descemet
membrane, and endothelium.  Any or all of these layers may be affected by
corneal dystrophy.

Congenital Endothelial Corneal Dystrophy (Congenital Hereditary Corneal
Dystrophy; Maumenee Corneal Dystrophy) is characterized by relatively clear
vision although corneal clouding may be detected by an eye specialist.

Crystalline Corneal Dystrophy of Schnyder (which begins early in life) is
characterized by oval or ring-form clouding of the central part of the cornea
with the edges remaining clear.  Involvement extends toward the extreme edges
(limbus) but usually leaves a clear ring inside this area.  Corneal
sensitivity to touch is normal.  Many small iridescent needle-shaped shiny
crystals can be seen in the clouded area.  These crystals are composed of
cholesterol.  The clouding is located in the front portion of the third layer
(stroma) just behind the Bowman membrane.  The front layer (epithelium) is
normal.  The lesions usually occur in both eyes.

Endothelial Epithelial Corneal Dystrophy (Fuchs Dystrophy) is
characterized by blurred vision, oversensitivity to light (photophobia), and
eye pain.  Acute attacks of inflammation of the cornea (keratitis fugax
hereditaria) may occur between 2 to 8 times a year.  Corneal erosion and
ulcerations may also occur and recur.

Epithelial Basement Membrane Corneal Dystrophy (Cogan Corneal Dystrophy;
Map-Dot-Fingerprint Type Corneal Dystrophy; Microcystic Corneal Dystrophy) is
characterized by gray coarse lines (maps or fingerprints) in the outermost
layer that cause errors in refraction in the eye.  Microscopic cysts are
found upon ophthalmologic examination.

Juvenile Epithelial Corneal Dystrophy of Meesmann is a genetic form of
Corneal Dystrophy.  This disorder usually appears during the first year or
two of life, beginning with symptoms of eye irritation.  Microscopic corneal
changes appear consisting of myriads of fine pinpoint cloudy spots in the
outer corneal layer (epithelium), and occasionally in the second layer
(Bowman membrane).  Vision is rarely impaired to a serious degree.

Francois-Neetens Speckled, or Flecked Corneal Dystrophy, is characterized
by scattered tiny white flecks occurring at all levels of the third corneal
layer (stroma) in semicircular, wreath-like, or point-shaped patterns.

Granular Type Corneal Dystrophy (Groenouw Type I Corneal Dystrophy) is
characterized by grainy changes in the cells in the third corneal layer
(stroma).  The clouding consists of grayish white granules with sharp
borders, mainly appearing in a disc-shaped area in the center of the cornea.
The edges of this shape and the cornea between granules is usually clear.
Glassy and transparent (hyaline) material separates the outer layer
(epithelium) from the Bowman membrane.  Clear vision is usually maintained
during childhood in patients with this type of corneal dystrophy.

Lattice Type Corneal Dystrophy (Biber-Haab-Dimmer Corneal Dystrophy) is a
genetic form of Corneal Dystrophy.  It is characterized by a "ground-glass"
appearance with grayish lines resembling cotton threads that are mainly
limited to a zone between the center of the cornea and the edges, and usually
not extending to the outer edge (limbus).  Rounded dots with distinct borders
are scattered everywhere in the cornea.  The cornea between cloudy spots is
relatively clear.  Vision is usually normal during childhood.  The
microscopic changes particularly involve the central portion of the cornea.
During adolescence, deposits that form a net-like pattern in the third
corneal layer (stroma) appear.  Recurrent corneal ulceration sometimes
occurs.  Progression to severe visual impairment by the fifth or sixth decade
of life often occurs.

Lipoid Corneal Dystrophy is a Corneal Dystrophy of unknown cause
characterized by haziness and thickness of the cornea, usually in the central
zone.  Fatty (lipoid) material is deposited within the stroma layer of the
cornea.  The Bowman membrane becomes replaced with white blood cells that
normally destroy foreign material and abnormal cells (macrophages).  The
outer cornea layer (epithelium) eventually becomes thicker.  Vision
impairment is slowly progressive.

Macular Corneal Dystrophy (Groenouw Type II Corneal Dystrophy) is a
genetic type of Corneal Dystrophy.  Onset of this progressive disorder is
usually between the ages of 5 and 9.  Tiny gray, pinpoint cloudy spots
develop.  Corneal sensitivity is usually lower than normal.  Painful attacks
with oversensitivity to light (photophobia), sensations of foreign bodies
inside the eyelid, and recurrent erosion of the cornea occur in most
patients.  This may be a localized disorder associated with other metabolic
disorders involving certain carbohydrates (mucopolysaccharides).

Marginal Corneal Dystrophy (Terrien Corneal Dystrophy) is a Corneal
Dystrophy of unknown cause.  Symptoms usually begin between the ages of 30
and 40.  The disorder is more common in males than in females.  It is
characterized by recurrent irritation of the eyes.  The stroma layer of the
cornea is replaced by loose connective tissue and the cornea gradually grows
thinner, usually at the upper edge.  The layer of the cornea called Descemet
membrane may start bulging forward, and the Bowman membrane may degenerate.
This disorder is slowly progressive.  The iris may protrude through a
perforation of the cornea.

Hereditary Polymorphous Posterior Corneal Dystrophy is characterized by
small empty spaces (vacuoles) in the back part of the cornea.  Vision is
usually not impaired, and blindness is rare.  This corneal deficiency may
also be associated with glaucoma, obesity, and wide spacing of teeth.

Reis-Bucklers (Buecklers) Corneal Dystrophy is a genetic form of corneal
dystrophy.  Symptoms usually start before age 2, may recur 2 to 3 times per
year, and gradually subside after the second or third decade of life.  The
disorder is characterized by recurrent epithelial erosions in both eyes
causing attacks of acute pain, lasting from one to three weeks.
Oversensitivity to light (photophobia) may also be present.  In the region of
the Bowman membrane, gray-white clouding may occur symmetrically in both
eyes, forming a delicate ring-pattern resembling curdled milk.  To the
examining physician the cornea resembles frosted glass.  The corneal clouding
appears denser in children than in adults.  The attacks gradually become less
frequent, usually ceasing completely with or without treatment.  However,
vision progressively deteriorates throughout life.

Salzmann Nodular Corneal Dystrophy (Nodular Cornea Degeneration) is
characterized by vision impairment and eye irritation.  Corneal infiltration
with small blood vessels, and degeneration of the cornea may occur.  The
three outermost layers (stroma, Bowman membrane and epithelium) may be
involved.  Bluish-white nodules appear in the outer layer of the stroma and
Bowman membrane, and may possibly appear in chains interspersed among blood
vessels.  The disorder usually occurs in persons with a history of other
corneal disease, such as inflammation or infection of the cornea and
conjunctiva.

Stromal Corneal Dystrophy is a term that includes the Granular, Macular,
and Lattice (Reticular) Corneal Dystrophies described above which occur in
the stroma layer of the cornea.

Causes

The following types of Corneal Dystrophy have no known cause:  Lipoid Corneal
Dystrophy, and Marginal Corneal Dystrophy (Terrien Corneal Dystrophy).

Congenital Endothelial Corneal Dystrophy (CD), and Macular Type CD are
inherited through autosomal recessive genes.  (Human traits including the
classic genetic diseases, are the product of the interaction of two genes for
that condition, one received from the father and one from the mother.  In
recessive disorders, the condition does not appear unless a person inherits
the same defective gene from each parent.  If one receives one normal gene
and one gene for the disease, the person will be a carrier for the disease,
but usually will show no symptoms.  The risk of transmitting the disease to
the children of a couple, both of whom are carriers for a recessive disorder,
is twenty-five percent.  Fifty percent of their children will be carriers,
but healthy as described above.  Twenty-five percent of their children will
receive both normal genes, one from each parent and will be genetically
normal.)

Crystalline CD of Schnyder, Endothelial Epithelial CD (Fuchs Dystrophy),
Epithelial Basement Membrane CD (Cogan CD; Map-Dot-Fingerprint Type CD;
Microcystic CD), Francois-Neetens Speckled or Flecked CD, Granular Type CD
(Groenouw Type I CD), Juvenile Epithelial CD of Meesmann, Lattice CD (Biber-
Haab-Dimmer CD), Polymorphous (Posterior) CD, and Reis-Bucklers (Buecklers)
Corneal Dystrophy are all inherited through autosomal dominant genes.  (Human
traits including the classic genetic diseases, are the product of the
interaction of two genes for that condition, one received from the father and
one from the mother.  In dominant disorders, a single copy of the disease
gene (received from either the mother or father) will be expressed
"dominating" the normal gene and resulting in appearance of the disease.  The
risk of transmitting the disorder from affected parent to offspring is 50%
for each pregnancy regardless of the sex of the resulting child.)

Salzmann Nodular CD (Nodular CD) is usually caused by other cornea
diseases such as leukoma, staphyloma, phlyctenular keratitis or pannus.

Affected Population

Corneal Dystrophies may affect persons of all ages.  Both sexes may be
affected in equal numbers.

Related Disorders

Corneal Dystrophy may be a secondary characteristic associated with the
following disorder.

Recurrent Cornea Erosion is caused by an abrasion of the cornea.  It is
characterized by pain in the eye, episodes of excessive tearing on awakening
in the morning (which increases with movement of the eyelid), and
oversensitivity to light (photophobia).  The eye tries to heal itself by
growing a new epithelium which is loosely attached to the Bowman membrane.
The epithelium may become detached as the eyelid opens and consequently the
eyelid may adhere to the cornea.  Growth of little sacs (vesicles), redness
and inflammation of the eye may also occur.  Some types of corneal dystrophy
may occur as a consequence of cornea erosion.

Therapies:  Standard

Corneal Dystrophies can often be successfully treated by surgically
transplanting a healthy cornea from a deceased human donor.  People with
healthy eyes are encouraged to donate corneal tissue in the (to be removed at
the time of death) so that patients with corneal dystrophy can be offered
normal sight.

Therapies:  Investigational

This disease entry is based upon medical information available through June
1988.  Since NORD's resources are limited, it is not possible to keep every
entry in the Rare Disease Database completely current and accurate.  Please
check with the agencies listed in the Resources section for the most current
information about this disorder.

Resources

For more information on Cornea Dystrophy, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     NIH/National Eye Institute
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

     Eye Bank Association of America
     1511 K Street NW, Suite 830
     Washington, DC  20005-1401
     [phone]

For genetic information and genetic counseling referrals, please contact:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY  10605
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

References

THE EFFECT OF EPIDERMAL GROWTH FACTOR ON EPITHELIAL HEALING AFTER PENETRATING
KERATOPLASTY IN HUMAN EYES:  A.S. Kandarakis, et al.; American Journal
Ophthalmol (October 15, 1984:  issue 98(4)).  Pp. 411-415.

RECURRENCE OF THE CLINICAL SIGNS OF LATTICE CORNEAL DYSTROPHY (TYPE I) IN
CORNEAL TRANSPLANTS:  D.M. Meisler, et al.; American Journal Ophthalmol
(February 1984:  issue 97(2)).  Pp. 210-214.

OPTOMETRIC MANAGEMENT OF FUCHS'S ENDOTHELIAL DYSTROPHY:  R.G. Carden;
American Journal Optom Physiol (September 1978:  issue 55(9)).  Pp. 642-646.