Dear Dr. Chris,
I have a 10 M/O Lab/Wiem mix. I am worried that she may have an eye problem. Her right eye looks normal but her left appears to have a very bright greenish reflection from the back of her eye. It does not seem to cause her any problems but worrisome none the less.
Brian, South Carolina
Having a 10 year old Weim/Lab mix can be quite an adventure. I’m sure there is no shortage of energy or entertainment in your house right now!
The green reflection you are seeing in the back of your puppy’s eye is called the tapetum lucidum. This is a normal part of the anatomy of the eye and is what is causing the green reflection you are seeing.
The tapetum lucidum is a reflective layer that causes the retina (the back of the eye) to appear green or yellow, or some color variation in between. This layer helps animals see better at night as it magnifies the amount of light and is most often noticed in animals that are nocturnal. Humans don’t have this so if you take a picture of a person, you get “red-eye” because the back of a person’s eye is filled with blood vessels with no reflective layer. If you take a picture of a dog, the reflection will appear yellow or green, in most cases.
If you are seeing different colors in the eyes of your dog, here are some possible causes:
- The tapetum lucidum may not be present in an eye that has a blue iris (pupil). This is normal and causes no harm.
- The tapetum lucidum may be more obvious in one eye if the pupil is abnormally dilated. If the pupils are the same size this isn’t a concern. If the pupils are a different size, then your canine friend should be evaluated by your veterinarian right away.
- Your puppy may have tapetal hypoplasia, a genetic defect where the tapetum is missing or underdeveloped.
- In some dogs (typically older dogs), there can be some serious causes such as progressive retinal atrophy or even a tumor, that may cause the eye to appear different.
If this is a recent change, your puppy should be examined by your veterinarian or a veterinary ophthalmologist. If she has always been this way, it is most likely due to a genetic variation which won’t affect her quality of life unless she is a hunter, foraging for food at night!
I hope this answers your question and keep taking good care of your puppy!
Dr. Chris Smith
Your dog’s favorite veterinarian