Facts on File Encyclopedia of Health and Medicine

(Jeff_L) #1

enucleation Surgical removal of a cancerous EYE
or a severely diseased or damaged eye. The OPERA-
TION, performed under general ANESTHESIA, takes
about an hour. After removing the eye, the surgeon
places an implant to fill the shape of the socket and
provide a means of attaching a PROSTHETIC EYE. A
pressure dressing stays in place over the eye orbit
for one to two days to minimize swelling and allow
the implant to become firmly rooted in the con-
junctival tissue. During this time it is common as
well as frightening for people to have difficulty
opening the other eye, as the eyes are accustomed
to functioning together. Once the bandage comes
off and the eyelid of the operated eye is free to
move, the eyelid for the unoperated eye resumes
normal functioning. Complete HEALINGtakes about
six weeks, during which time it is necessary to place
anti-inflammatory and antibiotic drops in the oper-
ated eye socket to keep swelling and the risk for
INFECTIONto a minimum.
Though the operation is uncomplicated and the
body quickly heals following the surgery, enucle-
ation can be a difficult procedure for people to
accommodate emotionally. Even when the eye
has been visionless for a long time, the prospect of
losing the eye troubles many people. The modern
prosthetic eye is typically such a close match for
the remaining eye that it is unapparent to other
people. Once the operative site heals, the eye orbit
(socket) and implant require little care or atten-
tion beyond cleaning the external eyelid area for
hygienic purposes.
See also ANTIBIOTIC MEDICATIONS; RETINOBLASTOMA;
SURGERY BENEFIT AND RISK MANAGEMENT; VISION
IMPAIRMENT.


episcleritis INFLAMMATION of the episclera, the
membrane that covers the sclera (fibrous outer
layer, the “white,” of the EYE). Most episcleritis is
idiopathic (occurs for unknown reasons), though
the condition sometimes accompanies AUTOIMMUNE
DISORDERS such as RHEUMATOID ARTHRITIS and
REITER’S SYNDROME. Episodes are self-limiting
though may recur over time, with each episode of
inflammation generally lasting 7 to 10 days.
Symptoms may include mild irritation and red-
ness, and occasionally a nodule (bump) on the
surface of the sclera. The doctor can diagnose epis-
cleritis by its appearance. Lubricating eye drops


help relieve the irritation until the inflammation
subsides. This is usually the only treatment neces-
sary. Some studies suggest a correlation between
episcleritis and hormonal shifts such as occur with
the MENSTRUAL CYCLEor MENOPAUSE. Episcleritis is
three times more common in women than men.
Episcleritis does not affect vision or result in any
long-term effects on the health of the eye.
See also CONJUNCTIVITIS; KERATITIS; SCLERITIS.

exophthalmos Bulging outward of the EYE,
sometimes called poptosis. Most exophthalmos
results from Graves’s disease and is a classic symp-
tom of this form of HYPERTHYROIDISM. Thyroid-
related exophthalmos results from swelling of the
tissues around the eye and within the orbit that
develops in reaction to the high levels of thyroid
HORMONEpresent in the circulation. Other causes
of exophthalmos include ORBITAL CELLULITIS, the
autoimmune disorder Wegener’s granulomatosis,
and FRACTUREof the facial or orbital bones that
push the eye out of place. Less common causes of
exophthalmos include tumors of the eye, OPTIC
NERVE, or BRAIN that protrude into the orbital
socket and ANEURYSM(ballooning of the arterial
wall) of the internal carotid ARTERY, a branch of
which runs behind the eye. Exophthalmos can
affect one eye (unilateral) or both eyes (bilateral),
and when bilateral can affect one eye more promi-
nently than the other.

Exophthalmos can cause significant and
permanent vision impairment, and
requires prompt treatment.

The diagnostic path begins with an OPHTHALMO-
LOGIC EXAMINATIONand blood tests to assess thyroid
function. When Graves’s disease or hyperthy-
roidism is the cause, treatment to restore appro-
priate levels of thyroid hormones often though
not always returns the eye to its normal position.
Persistent exophthalmos may prevent the eyelids
from closing over the eye, exposing the CORNEAto
excessive dryness and potential trauma. Untreated
exophthalmos results in VISION IMPAIRMENTthat can
progress to blindness.
See also AUTOIMMUNE DISORDERS;GRAVES’S OPH-
THALMOPATHY.

88 The Eyes

Free download pdf