Tips for simplifying ophthalmic exam in general practice

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When it comes to ophthalmic examinations, can be a scary experience for veterinarians. However, although the interpretations of findings can be challenging, the examination that leads to the interpretations follows a logical, anatomical order that does not necessarily require expensive equipment. Ron Ofri, DVM, PhD, DECVO, explained that the most important factors of the exam are not ophthalmic, such as darkening the exam room, a magnifying loupe, and a strong source of focal light.

During his lecture Ophthalmic Exam Made Easy, at the Veterinary Meeting & Expo (VMX) Conference in Orlando, Florida, Ofri, broke down how veterinary teams can make to make these exams easier for general practitioners. Throughout the lecture, he provided multiple steps veterinary professionals can follow to ensure these examinations are not as scary as they may appear to be.

Preparing for the examination

Before veterinarians begin their exam, they need to pay attention to the patient’s signalment. Multiple ocular conditions seen in pets, particularly in dogs, can be breed or age-related, meaning a general history should be taken and a comprehensive physical examination conducted. Ofri explained that many ophthalmic disorders can be manifestations of systemic disease, which is why a history and physical examination are important places to begin. During the examination and history, if neuro-ophthalmological abnormalities are present, such as anisocoria, blindness, or strabismus, the patient’s neurological systems should be evaluated because this can indicate a neurological disease.

As you get ready to begin your exam, Ofri listed these items that veterinarians will need to complete the examination:

• Schirmer Tear Test strips to measure tear production
• Fluorescein stain to diagnose corneal ulcers
• Topical anesthesia
• Tropicamide solution to dilate the pupil
• An ophthalmoscope.
• Fine forceps and swabs may be required to evert the lids.

Ofri explained that realistically, the only expensive item that is required for these examinations is an applanation or rebound tonometer. These are needed to diagnose and monitor patients with glaucoma. A cheap alternative is the Schiotz indentation tonometer, which can provide veterinarians with a reliable reading with the proper calibration and practice. However, Ofri warned that, in any case, veterinarians should not attempt to measure pressure with their fingers. If the clinic does not have a tonometer, veterinarians can refer patients with suspected glaucoma for measurement of intraocular pressure.

RELATED CONTENT: Corneal ulcers in general practice

Gross inspection

As the patient walks into the room, the veterinarian should be observing the pet because being in an unfamiliar place can highlight visual deficits which can be examined more in-depth later in the examination.

Ofri explained that careful hands-off observation of the patient from a distance is needed, and professionals should ask themselves these questions:

• Are both eyes open normally?
• Is there evidence of pain or photophobia
• Is the patient blinking normally?
• Are the eyes of normal size and position?
• Is there evidence of exophthalmos or buphthalmos?
• Are the pupils equal in size?
• Is the eyelid conformation normal?
• Is there evidence of entropion or ectropion, usually of the lower lid?
• Is the upper lid prolapsed?
• Is the 3rd eyelid elevated?
• Is their ocular discharge, and what is its nature if so?

After these questions are answered, Ofri explained the next step is checking the patient's orbital area to see if it is palpated to see if there are any abnormal swellings, fractures, etc. Veterinarians can use this opportunity to press on the globe through the upper lid of the patient, which can serve as a retropulsion test, and to proptose the 3rd eyelid, which allows inspection of its outer surface.

Next for the gross inspection is to inspect the eyelids. Veterinarians should carefully examine the skin looking for signs of dermatological disorders, just as alopecia, dermatitis, crusting, ulcerations, etc., as well as discharge. Veterinarians can evert the eyelids slightly to help visualize the conjunctiva lining of the patient's lids and 2 punctas. This moment can also be used to test the blink reflex by touching the skin around the eye.

Vision inspection

Testing a patient’s vision is most commonly done by evaluating the menace response, which is making sudden threatening gestures that are supposed to cause a blink response in the patient. Ofri explained that it is important to understand this response involves the cerebral cortex integration and interpretation, meaning it is not a reflex.

To complete the menace response, one of the patient’s eyes should be covered while they evaluate the other. It is important to also not touch the eyelashes or hair of the patient to cause any type of wind movement.

Touching the patient’s eyelashes or hair or causing wind movement can trigger a false positive response. Ofri recommends veterinarians consider making the menace gesture behind a glass partition of some kind. A false negative can also occur in the menace response, with some reasoning being facial nerve paralysis, which can be ruled out by testing the patient's blinking reflex, young age, and the patient’s mental state. However, there are additional ways to test vision besides the menace gesture.

“Another way to check vision is doing the maze test, checking the animal's ability to navigate an obstacle course. Now mind you, when people build an obstacle course, they sometimes have a tendency to build an obstacle course that's fit for a military commando unit. No need to make it so difficult, just a couple of obstacles… that can be navigated by a normal animal. And one advantage of doing a maze test or an obstacle course is that it can be conducted both in light and dark,” Ofri explained to attendees.

In conclusion

Before closing his lecture, Ofri told those in attendance at his session to think of their ophthalmoscope as their stethoscope, just like he tells his students. He went on to explain that for everyone’s first day in the clinic after veterinary school, you are not entirely sure what you are doing but you know you need to use the stethoscope on the patient, even though you may be unsure about what you are hearing. However, as you continue to do exams and practice, you begin to learn and can start diagnosing cardiac and pulmonary problems. To Ofri, this is the same with the ophthalmoscope.

“Okay, first 100 patients, I promise you, you'll not see a thing. Next 100 maybe you'll catch a fleeting glimpse of the fundus for 1 second, 2 seconds, 3 seconds, 4 seconds. The more you do it, the better you'll be committed, and you can recognize normal variations. Then when a blind patient comes into your clinic complaining of blindness, you can perform a proper ophthalmoscopic examination. But if the first time you're going to try it is on a blind patient, forget it. You have no hope. So please do an ophthalmoscopic exam on every patient that comes into your clinic,” he concluded.

Part 2 of this article will be released later this week so be sure to check in at dvm360.com to make sure you do not miss it.

Reference

1. Ofri R. Ophthalmic Exam Made Easy! Presented at: Veterinary Meeting & Expo; Orlando, FL. January 25-29, 2025.