Recurrent Uveitis
Recurrent uveitis, also known as 'moon
blindness' is one of the most common
inflammatory conditions affecting the
eye. One or both eyes may be
involved, and signs include tearing,
pain, sensitivity to light, clouding of the
cornea, and pus accumulation. The
iris may appear dull or gray, and the
pupil may be abnormally small. A
horse with recurrent uveitis may have
spasms of the eyelid causing the eye
to be partially closed.
A veterinarian can diagnose the
condition by administering a
fluroescein dye. The dye will appear
as a green color in the eyes of an
affected horse. The exact cause of
recurrent uveitis is unknown. However,
some possible causes are:
Leptospirosis (thought to be the
number one cause), bacteria,
parasitic, and traumatic. It is important
to establish a specific diagnosis
whenever possible which may require
tests such as: blood count, serum
biochemical profile, urinalysis,
leprospirosis-toxoplasmosis and
brucellosis titers, and fecal exam for
parasites.
After the original episode has been
successfully treated, the inflammation
and signs will disappear and the eye
may appear to be normal or almost
normal. At sometime in the future, if it
is recurrent uveitis, a set of
circumstances will cause the eye to
have another episode. The
circumstances can be internal; external
such as wind, dust, pollen; stress of
any kind; or due to stopping the
anti-inflammatory medicine
prematurely. With recurrent uveitis, the
episodes continue to occur. Each one
lasts a little longer and each time the
eye loses a little more sight.
Long term maintenance treatment will
often include aspirin, bute or banamine
on a regular basis in an attempt to
keep the inflammation from starting.
Many horses wear fly masks to cut
down on thy light and owners are also
using dietary supplements to help build
up the horse.
ERU is also called moon blindness
because historically its recurrence was
thought to be related with the phases
of the moon. It is believed to have
many different causes, such as
bacterial, parasitic, trauma, viral, or
immune disorders.
Uveitis is very painful to the
horse.
The most common signs
associated with uveitis are
- Constricted pupils
- Ocular discharge
- Squinting
- Redness to eyes and lids and
puffiness
The horse may also be sensitive to the
sun or any light.
Other signs include white cloudiness to
the eye, loss of balance, rubbing the
eye, tripping, matter or pus in the eye,
fever, anorexia, conjunctivitis, and
abnormal milk production.
Treatment
Treatment includes atropine for the
pain and to induce dilating of the pupil,
antibiotics, corticosteroids, and if
cause is believed to be parasitic,
diethylcarbamazine may be used to kill
the microfilaria.
The condition can be recurring, and
treatment should begin at the first
signs of recurrence (the reason it is
know as “recurrent uveitis”.)
Historically moon blindness was felt to
be tied to the cycle of the moon-thus
being called moon blindness. Anytime
you believe there is a problem with
your horse’s eyes, please consult your
veterinarian.
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