Ocular diagnostics (Proceedings)


Ocular diagnostics (Proceedings)

Aug 01, 2008

The veterinary technician [VT] plays a crucial role in many aspects of evaluation of the ophthalmic patient in our hospital. First and foremost the VT takes the history. This is not as simple as it sounds as you have the job of obtaining only the ophthalmology pertinent history or systemic history related to the eyes. As you know, people often want to tell you what the pet had for breakfast 3 weeks ago, how he ate it, and what came out the other end. We want to focus on a few points:

1. Which eye is the problem?

2. How long has it been going on for?

3. Have you used any medication for this problem? People often use medications from other pets or themselves or over the counter.

4. When was the last time you medicated?

5. Does your pet have any problems seeing?

6. Is your pet exhibiting signs of pain with squinting, tearing, redness or itchiness?

7. Has this ever happened before?

8. Is your pet otherwise healthy?

9. Is your pet on any medication or supplements?

I always recommend when owners are coming into the hospital that they bring with them any medication that they are using or have previously used for this condition. I had one owner come in who was using a Gentocin product on the eye that was prescribed for her other dog. The problem was that it was Gentocin OTIC. Ear medications CAN NOT go in the eye. Not only was it burning the poor little dog but it created a deep hole in the cornea that required a graft to save the eye.

In our hospitals where we do complete ophthalmic examinations, the VT also performs many of the diagnostic tests before the ophthalmologist comes in the room. Unless an ulceration is suspected, the VT will perform the Schirmer's Tear Test [STT], perform tonometry (a glaucoma test), and drop fluorescein dye in the eye. Your veterinarian may want to examine the pet first to determine which tests are necessary.

Ophthalmic examinations may be challenging on moving pets let alone any who really don't want anyone to stare into their eyes. The VT job is critical here in holding the pet properly. I will talk about this in particular and show videos of how we examine dogs and cats. We place big dogs on the floor backed into a cornea with a VT standing behind and reaching forward to hold the chin. Small dogs under about 40 pounds or those close to the ground like a big Basset are placed on the table. Cats are also examined up on a table and may be gently wrapped up in a towel to isolate the head. We do not do examinations under anesthesia as even most aggressive pets can be examined with proper handling techniques and anesthesia affects our results significantly.[ The exception is if pets are very painful from a physical trauma.] As you may well know, owners are often reluctant to express a concern about their pet biting until it is too late. If you have a suspicion from your initial meeting of the pet, you may want to ask 'Has your pet ever nipped when scared? The veterinarian will have her nose right up to your pet's muzzle so if there is any concern, I would like to get a soft muzzle'. Most people will value the vet's nose if there is any question.

It is important that the pet is held in spinal alignment. Head, neck, spine, tail should all be in one direction pointing towards the examiner. Not only does this allow evaluation of symmetry of the face, eyelids, pupils, responses, and reflexes, but this is important in an accurate tonometry. The pet should be held under the jaw with one hand and around the muzzle if possible with the other.

Schirmer's Tear Test must come first before any topical anesthetic or stain and preferably, hours after any topical ointment. The tear test strip is standardized to read a certain amount after 60 seconds. It provides much less valuable information if it is taken out before then. Even if a case appears to be staining the test strip abnormally high, do not be tempted to remove it. Abnormally high values are also of help with disease interpretation.