While I am not an ophthalmologist, and I don’t play one on TV, I am married to one… That means I am constantly told I am doing things wrong! (…and I usually am.) I am (slightly) kidding – but I do have a good excuse…I only had 3 days of ophthalmology as a veterinary student! So…you will learn from MY mistakes!
Let’s talk 5 common eye examination mistakes and how to avoid them!
1) When evaluating a patient for a corneal ulcer, don’t use a Wood’s Lamp. Unless you want to put the cornea into a mini fluorescent tanning bed, I would avoid the Wood’s lamp. The Wood’s lamps emit UV light and is used to fluoresce ringworm…not corneal ulcers.
What should you be using? You should be using a cobalt blue filter. The fluorescein looks the best under cobalt blue light. Hence, veterinary ophthalmologists best view fluorescein with the blue light of a slit-lamp, or other similar devices such as the Bluminator! So leave that Wood’s lamp for the ringworm cases…
2) When performing a Schirmer tear test, DON’T place the tear strip in the upper eyelid. The tear strip should be placed in the lower eyelid as the STT has been validated in this position. Why? When you pull down the lower eyelid there is a natural small puddle of tears called the lacrimal lake. Placing the strip in the upper eyelid will lead to a falsely low result as there is no lacrimal lake in the upper eyelid.
3) When performing a Schirmer tear test, if the tear test falls out in 15 seconds, you can not take this 15 second value multiplied by 4 and record this value as your 60 second result. When placing the strip properly in the lower eyelid, there is an initial rapid rise in the STT value due to the uptake from the lacrimal lake followed by a slower uptake of tears from steady state tear production. If you stop the time at 15 seconds, you may falsely record the rapid rise multiplied by 4 and get a falsely elevated STT value.
4) Don’t over interpret tonometry readings. The percentage that is reported along with the intraocular pressure (IOP) value is consistency and not accuracy. The tonopen has no idea what the pressure is inside of your patient’s eye, thus there is no way for this device to report how accurate your measurement is. Before you receive a final reading, you tap the eye several times and hear several beeps as the tonopen measures your values. When you get a final value, the percentage tells you how much each of your measurements vary between each other. So if you do the measurement the wrong way 5 times, it will report a low percent error for YOUR technique, not related to the true value for the patient.
5) Finally, make certain to get a good ocular history. Nothing is more frustrating than working through a case only to determine the history does not support that diagnosis or medication plan.
- When did the signs start?
- One or both eyes?
- Was there discharge?
- Worse at any time of the day?
- Previous medications used?
Ultimately, with a good history and good technique, we can “see” a nice improvement in our ocular examination and diagnostics.
Dr. Garret Pachtinger, DACVECC