January 12, 2012
Posted in Common Pet Conditions, Pet Health

In a dark room or in the dim light of the evening outdoors, you may only be able to identify your dog by the neon green glow of its eyes. It may be alarming to owners to see this hue the first time. The glowing green, light blue or soft purple can seem almost demonic at times, but don't let it fool you. It is simply a property of dogs' eyes that is different from humans.

Canine eyes react to light differently in the dark than humans' eyes do. Dogs, cats and many other animals have a surface in their eyes that is called the tapetum lucidum, a reflective surface that is located between the optic nerve and the retina. This layer operates like a mirror, reflecting the light in a way that allows animals to pick up more light when it is darker. It is this property of animals' eyes that allows them to see better at night than humans.

"This is an adaptive feature in animals who tend to be hunters at dawn and dusk," veterinary ophthalmologist Dr. Bill Miller told the news outlet. "The eyes of these animals are geared for low-light vision. They include dogs, cats, cattle, deer, horses and ferrets. However, humans and primates do not have the tapetum lucidum – and neither do squirrels because they are more active during the day – because their retinas are designed for brighter light vision."

Just as dogs' eyes come in different colors – from the warm chestnut brown of a chocolate Lab to the piercing blue of a Husky – the luminescence of them at night varies. According to the news outlet, the specific color of the glow varies depending on the animal and the amount of zinc or riboflavin that exists in the pigment cells within the tapetum lucidum.

It is important to know about your dogs' eyes so you can also recognize when something goes wrong. If you notice that your dog's eyes are inflamed or swollen, it may be caused by a bacterial infection. Your veterinarian may prescribe pet meds like Neo Poly Dex Ophthalmic to treat the condition. If your dog's eyes are glowy and greenish even in the light, it could be caused by normal aging, or could be glaucoma. If your dog suffers from glaucoma, your vet may prescribe medication like Timolol or Methazolamide. Pet owners should also keep an eye out for dry eyes in their dogs. Having pet supplies like LiquiTears or Puralube Vet Ointment on hand can help soothe dryness and irritation. 

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4. Angel Eyes for Dogs: Frequently Asked Questions
5. How to heal dry eyes in dogs