Why Do My Dog's Eyes Shine at Night?

Why Do My Dog’s Eyes Shine at Night?

Have you ever noticed that when you look at your dog or cat’s eye in the dark, they glow a yellowish/green color? Have you ever wondered why your pet doesn’t get “red eyes” in photographs?

This is due to a structure in the back of the eye called the tapetum lucidum. This is a reflective layer in the back of the eye that sits just in front of the blood filled layer called the choroid. The job of this layer of the eye is to reflect light back onto the retina a second time to amplify light in dark conditions. The color of the tapetum and its reflection can vary from a green, blue, orange or yellow hue. This coloration often changes over the first 3 months of life. Some dogs, similar to humans, do not have a tapetum. This is most common in dogs with blue eyes. Thus, when a photograph is taken, the tapetum is not present to create the colored reflection and therefore the red blood vessels in the back of the eye are visualized. This creates the “red eye” look.

If you notice a change in how your dog’s eyes are reflecting over time (duller or brighter) or there is a difference in the reflection between eyes, it is advisable to have the eyes examined. It could indicate an eye disease that needs to be addressed.