Glaucoma-associated pain results in mechanical sensitivity changes in dogs: A pilot study

Area of Science:

• Veterinary Ophthalmology
• Pain Management in Animals
• Animal Neurology

Background:

• Chronic, uncontrolled glaucoma can cause significant pain and discomfort in dogs.
• Assessing pain sensitivity in animals is crucial for effective treatment and management.
• Enucleation is a surgical procedure to remove an eye, often performed to alleviate pain associated with severe ocular disease.

Purpose of the Study:

• To investigate the impact of chronic, uncontrolled glaucoma on pressure sensitivity in dogs.
• To evaluate changes in pain sensitivity following enucleation of a painful, glaucomatous eye.
• To compare pressure sensitivity in dogs with glaucoma to that of healthy control dogs.

Main Methods:

• Quantitative sensory testing (QST) using electronic Von Frey (eVF) and blunt algometry (BA) was performed on dogs before and after enucleation.
• Cochet-Bonnet esthesiometry (CB) was used to assess corneal sensitivity in the remaining eye.
• Craniofacial ratio (CFR) and relative palpebral fissure width (RPFW) were measured to assess cranial conformation.

Main Results:

• Dogs with chronic glaucoma showed decreased sensitivity to mechanical stimuli after enucleation, indicating reduced pain perception.
• This decrease in sensitivity was observed both locally around the surgical site and at remote body locations.
• Cranial conformation, assessed by CFR and RPFW, was correlated with variations in pressure sensitivity.

Conclusions:

• Enucleation for painful chronic glaucoma in dogs leads to a significant reduction in mechanical sensitivity.
• Pain sensitivity changes occur systemically, affecting sites distant from the removed eye.
• Individual differences in cranial conformation may influence pain sensitivity modulation post-enucleation.