General Definition:
Dystrophies
are eye surface disorders for which the cause is more or less determined but
most likely genetic in origin. There are many dystrophies but taken seperatly
these are rare and orphan diseases. Amongst them are the following dystrophies:
Avellino's Dystrophy, Groenouw's
Dystrophy,
Reis-Buckler's Dystrophy or the genetic BIG-H3
Dystrophy a.k.a Granular Type III, Schnyder's Dystrophy, Meesmann's,
Cogan's or Microcystic Dystrophy, Lattice type II Dystrophy
(familiar amyloidosis),
Granular, Map dot fingerprint or Anterior (or Epithelial)
Basement Membrane Dystrophy, etc.
Reis-Buckler Dystrophy
The following
chapter on Reis-Buckler is taken from
Hope for Sight
(a Support group for Reis-Buckler
or Granular Type II Dystrophy in the USA)
Genetic Background:
Reis-Buckler Corneal Dystrophy (RBCD) is caused by
a genetic mutation found on Chromosome #5q31, in the BIGH3 gene, on exon4, at
codon 124. If no mutation is present, the codon normally codes for the amino
acid Arginine. In RBCD, the amino acid Leucine is produced. Scientists are not
sure at this point what part the mutation plays in Reis-Bucklers, but it may
have to do with the incorrect amino acids being made and therefore affecting the
way the epithelium, (a thin layer of the cornea) adheres to other cells in the
cornea.
Diagnosis:
In Reis-Buckler corneal dystrophy, gray hazy
deposits, (crystillizations) may be seen. It is also not known yet whether the
incorrect production of amino acids results in these deposits. The gray hazy
deposits or crystallizations are one of the signatures of RBCD. The deposits
form a symmetrical pattern in the corneas of both eyes. This can usually be
seen in a slit lamp examination at a qualified physicians office and are one of
the first clues pointing in the direction of corneal dystrophy- specifically
Reis Bucklers. RBCD can also be seen by examining cornea cells in a laboratory.
Painful recurrent corneal abrasions(erosions), are often what bring patients in
for examination. The erosions can be the result of trauma to the cornea, or can
be spontaneous. Many other corneal dystrophies also exhibit recurrent corneal
erosions, so DNA testing may be the next step the physician will choose to give
a diagnosis. In fact, it is this testing that is the most accurate way to
diagnose corneal dystrophy.
Symptoms:
Symptoms of Reis-Buckler
include visual distortion, eye pain, corneal erosion, extreme photophobia (light
sensitivity), excessive tearing, and the eyelid swelling shut. We often lump all
of these symptoms together and call them an episode. This is because the
symptoms of RBCD are somewhat spontaneous. While there may always be light
sensitivity and distortion with this disease, when we talk about an episode we
are referring an intense period of 3-10 days when symptoms are occuring. For
Example, sometimes the symptoms of an episode occur with corneal erosion and
sometimes they occur without corneal erosion. Episodes can alternate between
both eyes. In our daughters' case, often the “good” or non-affected eye remains
closed in sympathy with the “bad” or affected eye. As an episode resolves, the
pain will decrease and often the good eye will open and then the bad eye will
follow. At this point light is still not well tolerated and it may be painful to
do any activity that requires concentrated focus of the eyes for any length of
time. Episodes are often worse or more intense in the middle of the night, first
thing in the morning, or after naps, as the eye tends to “dry out” during these
periods and the eyelid may try to “stick” to the cornea. The first few days of
the episode are usually the most painful. The good news that we have found is
that when our daughters are episode free, they are able to live a normal healthy
life.
Prevention, Pain Management
and Treatments:
For a typical episode, ophthalmologists will
usually tell patients to keep the eyes well lubricated and they will offer
suggestions as to which type of lubricants. Some of the lubricants we have used
have been Genteal, Refresh PM, and Muro 128. Doctors will sometimes prescribe
antibiotics to prevent infection if there is an erosion during an episode. Some
of the prevention measures we have used for our children are: cool mist
humidifiers, sunglasses, cool or warm moist compresses, plenty of hydration, and
lots of regular rest. We stay in contact with our doctors and keep them current
on the progress of our children. We have also entered a study for corneal
dystrophy, (see below). For pain management we have used over the counter
pain-relievers, lubricants, room darkening shades, soothing music, distractions,
and even the family pets who offer their “creature” comforting as well.
If an episode does not resolve itself, there are
other more aggressive treatments that can be pursued to help stop recurring
erosions and increase visual acuity. Because Reis-Buckler Corneal dystrophy is
rare, there is no set management plan for the disease; and as of yet, there is
no cure. This means that the following treatments are not permanent solutions
for Reis-Bucklers, but have some effectiveness against the disease. It also
means that all specialists will not treat all cases of RB in the same way, which
is one of the reasons we started this website, so as a group we will be aware of
all of the different ways RB is being treated and be able to share that
information with each other and our doctors.
These are the treatments we know of so far:
First; punctal plugs, these plugs are used to block the tear ducts that drain
the tears from the eye, thus helping to keep the eye naturally lubricated and
preventing the cornea from drying out and sticking to the eyelid, second;
anterior stromal micropuncture, a procedure where a needle makes microscopic
holes in the cornea to help the epithelium adhere better and prevent future
erosions, third; PTK, a laser procedure which takes away the top layer of the
cornea and clears away the haziness so vision is increased, and last; corneal
transplantation, one of the most successful types of transplants, where a
donated cornea replaces the damaged cornea. This is also not a cure, because the
disease is in the DNA and it is only a matter of time before the new cornea is
affected, (although some patients never do experience a recurrence). In our
opinion because the mutation for RB continues producing incorrect amino acids
regardless of the procedures done on the cornea itself, there probably will not
be a cure for Reis-Bucklers unless a way can be found to correct or combat the
malfunctioning DNA.
.... Dystrophy
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