OPHTHALMOLOGY
All photos courtesy of Dr. Brad Holmberg.
Figure 1: A 10-year-old Boston terrier that presented for a red
eye. Note the swelling and redness of the conjunctiva. This
was secondary to a cancerous tumor growing under the con-
junctiva. A biopsy of the tissue revealed a mast cell tumor. The
dog was sent to an oncologist and unfortunately had a poor
prognosis for long-term survival. All photos courtesy of Dr. Brad
Holmberg.
rectly, know about the underlying causes and under-
stand treatment options for each species.
Figure 2 shows a 6-year-old Labrador retriever that in-
itially presented to the referring veterinarian for a red
left eye. After one day of treating with a triple antibiot-
ic ointment, the conjunctivitis got much worse, with
extensive redness and swelling as noted in the image.
This is secondary to a toxic reaction to neomycin, a
common antibiotic in several ophthalmic medica-
tions. Stopping the neomycin and treating with a top-
ical corticosteroid anti-inflammatory helped resolve
the clinical signs. The cause of the first-noticed con-
junctivitis was unknown and suspected to be allergic.
Dogs and cats often present with similar clinical signs
during an exam, including red, puffy eyes and, fre-
quently, ocular discharge. This discharge may be wa-
tery or it may have a mucoid or purulent consistency.
The type of discharge may suggest the underlying
cause, but it’s by no means definitive.
Figure 2: A 6-year-old Labrador retriever that initially presented
to the referring veterinarian for a red left eye. After one day of
treating with a triple antibiotic ointment, the conjunctivitis got
much worse, with extensive redness and swelling as noted in
the image. This is secondary to a toxic reaction to neomycin,
a common antibiotic in several ophthalmic medications. Stop-
ping the neomycin and treating with a topical corticosteroid
anti-inflammatory helped resolve the clinical signs. The cause
of the first-noticed conjunctivitis was unknown and suspected
to be allergic.
This exam and the test results may definitively diag-
nose the cause of the conjunctivitis or suggest other
causes, such as allergy or infection. If I suspect infec-
tious conjunctivitis, I’ll conduct further testing, includ-
ing taking conjunctival samples, blood samples or
both to confirm the presence of an infectious cause.
The Canine Window
Figure 3 shows a 8-year-old mix-breed dog that pre-
sented for conjunctivitis. Note the swelling along the
top of the eye with an orange-appearing mass effect.
A tissue biopsy revealed lymphoma. Treatment by an
oncologist involved oral and intravenous chemother-
apy, which helped resolve the signs and prolonged
the dog's life for several years.
If a patient has had conjunctivitis for a day or two,
that’s fairly common and we may let it run its course.
If it’s been going on for several days and there’s sig-
nificant discharge, redness, squinting or cloudiness of
the cornea, it’s time for a thorough examination.
Diagnostic Rundown
When I am presented with a dog or cat with clinical
signs of conjunctivitis, I conduct a series of diagnostic
tests to try to determine the underlying cause. These
tests include measuring tear levels with a Schirmer
tear test, performing tonometry to assess intraocu-
lar pressure to look for glaucoma, placing a special
stain on the cornea to look for corneal ulceration and,
most important, performing a thorough exam using
slit lamp biomicroscopy.
Figure 3: An 8-year-old mix-breed dog that presented for con-
junctivitis. Note the swelling along the top of the eye with an
orange-appearing mass effect. A tissue biopsy revealed lympho-
ma. Treatment by an oncologist involved oral and intravenous
chemotherapy, which helped resolve the signs and prolonged
the dog's life for several years.
Issue 06 | DECEMBER 2017 | 9