Quiz: About blindness in dogs

RESTRICTED CONTENT

NeuroPetVet is a subscription-only website created for veterinary medical professionals.

New user?

Sign up today!

Note to students/interns/residents: To view the entire site, you must sign up for an account first, then email proof of student/trainee status to us so that we can ugrade your acccount.

Already have a subscription?

Login now

If you have a STUDENT MEMBERSHIP and you are logged in, you are likely seeing this page because we have not received proof of student status. Please submit proof of student status, along with your month/year of expected graduation or when you finish your internship/residency, so that we can update your account to full access to the site.

If you have a STANDARD MEMBERSHIP and you are logged in, you are seeing this page because access is limited to student and premium members. If you'd like to view all content on the site, please consider upgrading to a premium membership.

 

2 replies
  1. Sina
    Sina says:

    Thank you for this amazing website!
    I do not understand why the presented dog has an incomplete PLR on both sides. I thought that the PLR should have also been negative on both sides. It would be great if you can explain me the pathophysiology.

    Reply
    • neuropetvet
      neuropetvet says:

      Hi, Sina. Thanks for the compliment!

      It is not uncommon for a functionally blind animal to have an intact PLR if they have a prechiasmal disease (i.e., retina, optic nerve, optic chiasm). Severe disease may lead to an absent PLR. However, the afferent fibers for PLR seem to be more resistant to disease than the visual pathway fibers and it only takes a few intact axons to generate a PLR. As a result, while the PLR may be abnormal, it is often still present.

      The PLR is rarely abnormal in animals with postchiasmal lesions as the afferent PLR fibers have already left this common pathway toward the midbrain.

      Hope this helps!

      Reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.