Discharge may be infection, sign of disease

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Annie has a thick yellowish discharge in her eyes, and the 10-year-old poodle mix's eyelids are reddened from being rubbed on the carpet.

Diagnosis would begin with a physical exam. Let's establish that Annie's problem is confined to her eyes. The discharge is thick and ropey and nowhere near the liquid consistency of normal tears. Our first step would be to measure tear production by using small paper strips inserted between the lower eyelid and the lower part of the eyeball. This is known as the Schirmer tear test. The eyelids are closed and the strips held in place for 60 seconds; then the tear line measured.

Next up would be a check for bacterial infection and ensuring the corneas have not been scored. For Annie's comfort, her eyes would be numbed with an eye drop. The eyes would then be swabbed and the culture placed on a microscope slide to test for a bacterial infection. The cornea, which covers the iris, is then checked for damage. If it were ulcerated, it would cause discomfort, redness and discharge from the eye. This test is done by introducing a fluorescent stain into the eye and then exposing the eye to an ultraviolet light. If there is corneal damage, there would be an area of stain uptake corresponding to the damaged spot. If there is no uptake, we can assume the cornea has not been compromised.

Further testing would rule out glaucoma. This disease occurs as a result of increased pressure inside the eyeball. If left unchecked, glaucoma can lead to blindness. It is a painful disease, and also leads to redness and discharge. An instrument that indirectly measures the intraocular pressure would determine whether Annie has glaucoma.

There may be other tests necessary, but for our discussion, let's state that the corneas do not show any damage based on the stain test and the intraocular pressures are normal. Further, let's say the eye culture shows a staph infection (Staphylococcus pseudointemedius). This is a secondary infection. The primary problem is keratoconjunctivitis sicca, or abnormally low tear production — shown by the Schirmer strips.

An antibiotic eye ointment would treat the secondary infection and artificial tear ointment would moisten Annie's eyes and an eye ointment would help increase natural tear production. Good long-term management of the problem is expected with this treatment.

Jeff Kahler is a veterinarian in Modesto, Calif.