Ocular diagnostics (Proceedings)


Ocular diagnostics (Proceedings)

Nov 01, 2010

"You miss more for not looking than not knowing".

The ability to accurately perform ocular diagnostics plays a crucial role in many aspects of evaluation of the ophthalmic patient.

First and foremost, take the history:

     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. Not only was it burning but it created a deep hole in the cornea that required a graft to save the eye.

Ophthalmic examinations may be challenging on moving pets let alone any who really don't want anyone to stare into their eyes. Training the veterinary technician (VT) to properly restrain patients is critical in thoroughly examining the patient. 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 corner 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. If you have a suspicion of a potential biter, you may want to ask 'Has your pet ever nipped when scared? I will have my nose right up to your pet's muzzle so if there is any concern, I would like to get a soft muzzle'.

Ideally the pet will be looked at in a relaxed state before you even lay hands on them to determine if symmetry is present. I then do a quick summary neurologic examination of sensation and motor to the eyelids, ears, and globes as I am talking to the owner.

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 critical in an accurate tonometry. The pet should be held under the jaw with one hand and around the muzzle if possible with the other.

Vision testing is very important. It's not uncommon to zero in on the problem without checking to see if the patient can see! Feel comfortable doing a menace to assure you know the dog has vision out of each eye. Cover one eye with your hand that is holding the head and wave the other hand from down low, across the visual field, to above the head. Do no push toward the head and illicit a sensation response from the air movement. A basic ocular examination is best done systematically and from front to back....look at each structure (eyelid margins, conjunctiva including the third eyelid, cornea, anterior chamber especially ventrally, iris, lens especially the periphery, vitreous, and retina) every time. Again, "you miss more for not looking than not knowing". If you don't have an eye exam form in your clinic, create diagrams within your SOAP sheet to refer back to for follow-up or in order to allow another veterinarian to pick up.