Development of reference intervals for pupillometry in healthy dogs

Area of Science:

• Veterinary ophthalmology
• Autonomic nervous system research
• Animal welfare science

Background:

• Pupillometry measures pupil size and reactivity, reflecting autonomic tone and offering potential for assessing nociception and emotion in animals.
• Infrared pupillometry enhances accuracy compared to subjective methods for determining the pupillary light reflex.
• No published studies currently provide normal reference intervals for automated pupillometry in dogs.

Purpose of the Study:

• To establish de novo automated pupillometry reference intervals for healthy canine eyes.
• To provide a foundational dataset for future research utilizing pupillometry in veterinary medicine.

Main Methods:

• Automated pupillometry was performed on 126 healthy canine eyes using a handheld pupillometer.
• Key parameters measured included maximum and minimum pupil diameter, percent constriction, latency, constriction velocities, and recovery time.
• One measurement was recorded per eye.

Main Results:

• Reference intervals were established for: MAX (6.05-11.30 mm), MIN (3.76-9.44 mm), CON (-37.89 to -9.64 %), LAT (0.11-0.30 s), ACV (-6.39 to -2.63 mm/s), MCV (-8.45 to -3.75 mm/s), ADV (-0.21-1.77 mm/s), and T75 (0.49-3.20 s).

Conclusions:

• The developed reference intervals are essential for advancing pupillometry as a pain assessment tool in dogs.
• This study provides critical normative data for canine pupillometry.
• Facilitates future research into the application of pupillometry for objective physiological assessments in veterinary patients.