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Thyroid-Related Eye Problems
(Grave’s Disease)
Grave’s disease (hyperthyroidism) is a medical condition in which an
over-active thyroid gland secretes an excess amount of thyroid hormone. As a
result, you may have an enlarged thyroid gland, palpitations, fast pulse,
profuse sweating, high blood pressure, irritability, and a number of symptoms
related to the eyes.
If you have been diagnosed as having a thyroid condition, a
medical history may suggest that your eye problems are related to it. On the
other hand, sometimes the presence of eye symptoms is the first sign of thyroid
trouble.
What are the
Symptoms?
In the early stages,
the most common eye involvement is lid
retraction, a pulling upward of one or both of the upper eyelids. It gives
the patient the appearance of staring or being “wide-eyed”. Since the eyes are
more exposed to the air, they will feel dry, and in response, the tear glands
may secrete more tears than normal. When lid retraction is severe, the eyelids
do not close completely, even when you blink. This will make the surface of the
eyes even drier, especially during the night when you are sleeping. It can
cause exposure keratitis (corneal
inflammation), which in turn, may lead to corneal ulceration.
During the acute phase of Graves’ disease, but surprisingly,
even more commonly after treatment of
the thyroid problem, the eyeballs may begin to protrude or bulge. Called exophthalmos or proptosis, the condition is thought to occur from an inflammatory,
auto-immune response in the eye socket that causes swelling, and the swelling
pushes the eyeball forward. At times the swelling can become as severe as to
endanger the health of the optic nerves.
The same type of inflammation and swelling can also involve
the eye muscles. This may cause double vision (diplopia) because the muscles
are not able to coordinate the eye movements. Another effect of the swelling
may be puffy or baggy eyelids.
Examination
Your pupils will be dilated (enlarged) with eye drops and
you will have a complete eye examination, including visual fields and an eye
pressure check. An instrument called an exophthalmometer will be used to
measure how far forward the eyes have protruded from the eye socket. This
instrument does not ever tough the eyes. X-rays of the orbit may be taken to
help determine the cause of the eyes’ bulging and to rule out an orbital tumor.
Treatment
The treatment for Grave’s disease includes a combination of
drugs, surgery and/or radioactive iodine, to restore normal function of the
thyroid and normal thyroid hormone levels in the body. Even after successful
treatment; however, it is not unusual to find the eye problems persisting or
even continuing to progress for a while. Usually the eye condition will
eventually stabilize.
You can help alleviate the drying of the eyeball surface by
using artificial tears eye drops. A lubricating ointment can help prevent
corneal drying while you sleep. If drying is severe and exposure keratitis is a
problem, you may need a minor surgical procedure, known as tarsorrhaphy, to attach the outer corneas of the eyelids together,
narrowing the eye opening and keeping the upper eyelid from pulling upward.
Later, if the condition improves and lid retraction lessens, the surgery can be
undone. After the disease has stabilized, you may wish to have cosmetic surgery
to lessen or eliminate the lid retraction.
If bulging of the eyes is severe and corneal exposure or
optic nerve damage is not manageable, you may require an operation known as decompression. This involves partial removal
of the bone around the eye socket to enlarge the space and relieve the pressure
on the eye. X-ray treatment may also help, but the results are often
unpredictable.
The double vision occurring in Grave’s disease is difficult
to treat. Swelling of the eye muscles may sometimes be helped to some extent
with cortisone-related medications. (Steroids) Long term use of these drugs can
often create serious side effects. Some relief may be obtained by adding prisms
to the eyeglasses. Otherwise, eye muscle surgery may be necessary but
unfortunately, even this may not be successful. As a last resort, double vision
can always be relieved simply by covering one eye with a removable patch.
The surgical treatment of many of the problems related to
thyroid eye disease is often performed in stages. It is rare that a patient
regains his or her original appearance, but with persistence and patience, a
cosmetically acceptable result is very often achieved.
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