Tearing
The tear film on the surface of the eye is a critical component
of maintaining vision. Tears nourish and lubricate the surface
of the eye as well as wash away debris. A smooth, balanced
tear film (consisting of water, oil and mucus) also allows
light to enter the eye in an optimal fashion. If there is
a disturbance of the tear film, patients will often experience
tearing, burning, irritation and most importantly blurred
vision. Patients who experience tearing either have a problem
with tear production or tear drainage.
Increased Tear Production and Dry Eyes
The eye has two sets of structures that produce tears. Smaller
tear glands help maintain a baseline level of moisture on
the surface of the eye. Unfortunately, inflammatory conditions
like rheumatoid arthritis, Sjogrens disease as well as aging
and menopause lead to decreased tear production. As tear production
diminishes, the surface of the eye starts to dry out. Further,
inflammation of the oil glands along the edge of the eyelid,
common in patients with roseacea, also causes early breakdown
and evaporation of the tear film. The brain senses the eye
is both dry and irritated and in turn signals the main tear
gland to flush the eye. As a result, the dry eye paradoxically
tears and becomes watery. Patients with dry eyes note intermittent
tearing of the eyes during activities like reading, driving,
watching TV, using a computer or going outside on a windy
day.These all cause the eye to dry out because the eye blinks
less during these activities. The treatment for dry eyes includes
1) replacing tears with artificial lubricants which can be
bought over the counter, 2) medications like Restasis that
decrease inflammation in tear glands and encourages natural
tear production to resume and finally 3) plugging of the tear
drain.
Other causes of increased tear production exist like allergies,
infections and eyelashes poking the eye. These conditions
can often be found during examination.
Blocked Tear Drain
While most patients with tearing have some form of dry eye,
another important cause of tearing is a blocked tear drain.
The tear drain has an entrance in the inside corner of both
the upper and lower lids. They join together to form the tear
drain duct that runs from the inside corner of the eye into
the nose. The presence of the drain explains why we taste
our tears or eye drops. An obstruction of the drain can be
congenital or acquired later in life.
Congenital tear drain obstructions occur in 6% of newborns
and fortunately 90% of these resolve on their own in the first
year of life. Other conditions may cause tearing in newborns,
thus all babies with tearing should be examined. During the
first year of life massage of the tear drain along with intermittent
use of topical antibiotics (if there is discharge) is the
best course of action. After age one, surgery that involves
probing the tear drain under anesthesia, is utilized to open
the drain. This surgery is over 90% successful. In the few
cases that fail to respond, a second surgery can be performed
with the insertion of a temporary stent or dilation of the
system using a special balloon probe. Rarely is bypass surgery
of the tear drain needed in children, but it is highly effective.
Acquired tear drain obstructions most commonly occur in adults,
especially after the age of 50. Still younger individuals
may develop scarring from a bad infection or other problem
in the eye. Patients with a blocked tear duct almost always
complain of constant tearing from the eye that runs down their
face. This diagnosis is made in the office after a thorough
exam and several office tests. When an obstruction is present
in the adult patient probing, balloon dilation and stenting
can sometimes be used however most patients require tear drain
bypass surgery. This is done under anesthesia in the operating
room. Two approaches can be used: either an external incision
on the side of the nose can be used to open the system form
the outside to the inside of the nose or more recently, working
form the inside the nose, the system can be opened from the
inside to the out thus avoid an external incision. Either
way, the surgery is 80-90% successful.
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