Do All Dogs’ Eyes Glow the Same?
The tapetum is a unique biological feature. Like anything else on a dog, it doesn’t develop exactly the same way in every dog. It’s another thing that makes your pup unique!
Some dogs have a larger tapetum than others. Furthermore, the cellular makeup can vary. Remember: The tapetum tissue gets its reflectivity from zinc or riboflavin.
In some dogs, the tapetum has more zinc. Others might have more riboflavin, while others have a healthy mix of both.
Interestingly, some dogs don’t have tapetum at all! Recent estimates show that around 1.9 percent of dogs lack the tapetum. It’s a small percentage, but they exist.
As you probably guessed, those dogs don’t have night vision. But their eyes can still glow in the right conditions as light reflects off the blood vessels in the back of the eyes!
Overall, the color of that signature eye glow varies based on the cellular makeup of your dog. Factors like breed, eye color, and coat color come into play.
So what color can you expect to see from your dog’s eyes?
Below is a general color chart to give you a better idea of the color variation. It includes some popular breeds and coat colors. These colors are the norm. However, there are no guarantees.
There are some canine outliers with unique tapetum tissue. If anything, use this color chart as a loose guide rather than concrete scientific evidence.
Curious about puppies? If you spend a lot of time around young dogs, you know that their eyes change dramatically as they grow. You can’t even see their eye color at birth because they keep them close for several weeks!
When they finally crack those eyes open and look into the world for the first time, the eyes are noticeably brighter than adults of the same breed.
The eyes lack pigmentation for several months. Eventually, they develop into the dog’s “true” eye color. As you can imagine, the color of the reflected glow differs, too.
The glow is usually the same as blue-eyes dogs when the eyes are light and pigment-free. It’s orange or red. The color will gradually change over several weeks and months.
By the three-month mark, most puppies are at their final color. The same goes for the reflected glow.
Why Do Dog’s Eyes Glow Different Colors?
The color of the eye’s reflective glow depends a lot on the individual ocular chemistry of the dog, so there can be changes in hue even within the same breed.
This is because the tapetum is reflective. After all, its cells contain between 11 and 15 layers of cells with the metal chelate, zinc cysteine. Zinc cysteine acts as the metallic mirror. Each dog has different amounts and ratios of these reflective compounds in the tapetum, causing different color glows.
Remember that this is not the same as a cat’s eyes, where the reflective material is riboflavin or a mix of riboflavin and zinc.
This is one of the reasons for making sure dogs get enough zinc and sulfur-bearing amino acids in their diet. These include methionine, cysteine, and taurine. If you want to read more about maintaining your dog’s eye health, read our article on taking care of dog’s eyes.
Why Do My Dog’s Eyes Glow In The Dark?
Dogs’ eyes glow in the dark because they are carnivores and their eyes reflect light to give them better night vision for hunting. Their eyes have evolved a reflective surface behind the retina and in front of the optic nerve called the tapetum lucidum. It reflects incoming light back to the retina so that light-sensitive cones and rods have a second chance to pick it up. This is a nifty way to “recycle” or make the most of light in the dark.
So just like a mirror, if you shine a light in your dog’s eyes, it will reflect back at you. This is just one way that the canine vision differs from ours. They also have bigger eyes that can collect more light and rods, which are light-sensitive cells. On the other hand, they have fewer cones than us, meaning they can see fewer colors.
And they even have a third eyelid, called the nictitating membrane. Because of all these intricacies, keeping our dog’s eyes clean should be part of our daily routine, and recommend natural dog eye wipes to wipe away any discharge or debris to prevent infection.
If you want to read more about a dog’s nictitating membrane, you can see our article on dog eyelids.
In general, creatures active during the day, such as us, primates, pigs, squirrels, and even kangaroos, do not have the tapetum lucidum. Other animals have evolved very different tapetum surfaces. For example, a crocodile has a retinal tapetum, while carnivores like dogs and cats have choroidal tapetum cellulosum.
The fact that carnivores generally have glowing eyes may be one of the reasons we find eye shine so spooky and eery. Deep down, humans probably know that glowing eyes in the dark can mean danger.
Red Eyes in Your Dog Here’s Why and What to Do
âPuppy dog eyesâ gets dog parents every time. Itâs been proven that gazing into your petâs eyes produces oxytocin and promotes bonding. They are the epitome of the âpleading faceâ emoji. Irresistible.
It could be something more than cuteness, though. If your dogâs eyes have been looking a little red or cloudy lately, or if youâve noticed theyâre pawing at, rubbing, or showing signs of irritation around their eyes, you might need to make an appointment with your vet.Â
Eye problems in dogs are no joke â dogs can suffer from a host of health conditions including glaucoma, conjunctivitis, dry eyes, cataracts and more. Some eye disorders occur more often than others (a dogâs breed usually plays a role).
âAs a general practitioner, I was often presented with problems such as conjunctivitis, dry eye and corneal ulcer,â says Dr. Christine Lim, DVM, DACVO, a veterinarian in Chicago. âNow that I specialize in ophthalmology, I more often see cataracts, glaucoma and retinal disorders.â
To understand eye problems in dogs, it helps to know a little bit about how their eyes function. A dogâs eyes work much like a camera. Light enters through the pupil, and the iris controls the amount of light allowed in. Light then passes through the cornea and lens, which focus the light on the retina, a layer containing color-sensitive cones and motion- and light-sensitive rods, which convert light into electrical signals. The cones and rods send these signals via the optic nerve to the brain, which constructs an from them. Related article
Dogs have only two types of cones, compared with the three types in human eyes. As a result, dogs donât see as many colors as do people. Dog eyes also contain structures not found in a camera, such as the gel-like vitreous humor that fills the eyeball and gives it shape. Canine eyes are different than human eyes in that they have a third eyelid called the nictitating membrane, a thin whitish-pink tissue that protects the eye. And unlike humans, dogs have a reflective lining behind the retina called the tapetum lucidum; itâs what makes dogsâ eyes glow eerily when light hits them. Itâs also what allows them to see in dimmer light.
The visual streak is a horizontal band in the retina right above the optic nerve; this area has the highest concentration of rods and cones, and vision is sharpest here. The visual streak varies greatly among breeds, and studies suggest that different breeds see the world differently. In dogs with long heads like wolves, the streak is wide, with the nerves evenly distributed. The shorter a breedâs head, the narrower (more circular) the streak tends to be. Pugs, for example, have a small spot of sharp vision â an âarea centralisâ â as humans do. Even within breeds, the visual streak can vary from type to type.
All of these features equip a dog to be a good hunter under various light conditions. The tapetum lucidum improves a dogâs vision in low-light, as does the high proportion of rods to cones, giving dogs better vision at night than humans. A rod-dense retina also makes dogs excellent at detecting motion and shapes. Because most dogsâ eyes angle slightly to the side, they have a wider field of view than humans. When a wide field of vision combines with a wide visual streak, as in a German Shepherd, a dog can see the whole horizon at once (instead of having to scan the eyes back and forth as humans do).
With keen senses of smell and hearing, dogs donât need to see well up close; in fact, near vision is blurry in long-nosed dogs. (Short-nosed dogs, with their human-like area centralis, do appear to see well up close. Though the area centralis may lessen their ability as hunters, it may make them better lapdogs, more able to âreadâ their ownersâ faces.) Overall vision is also less sharp.Related article
They canât take in as many colors as you can, but their world isnât just black and white.
Below are the most common eye problems in dogs. (Note: Some dog breeds are more prone to eye problems than others, and a mixed-breed with one of those types in the mix could also be affected.)
Conjunctivitis is a condition in which the lining of the eyelids and the front of the sclera (the white of the eye) become inflamed. It can be caused by infection, an object in the dogâs eye, an allergic reaction, dry eye, a scratch, or even smoke or dust, and can also be a symptom of other diseases. Treatment depends on the cause.
Dry Eye is when not enough tears are produced to keep the eyes properly lubricated. Dogs may inherit this condition; among the dog breeds at higher risk are the American Cocker Spaniel, English Bulldog, Pug, Lhasa Apso, Pekinese, Shih Tzu, and West Highland White Terrier. Small, flat-faced dogs sometimes have eyes that bulge so much that their eyelids cannot close, which makes the surface of the eyes to dry out.
Dry eye may also result from an immune system reaction, an injury or a drug side effect. Dryness can be a serious problem for dogs because dry eyes are easily irritated and may develop conjunctivitis or corneal ulcers. Artificial tears, good eye hygiene, anti-inflammatory drugs and/or cyclosporine ointment (Optimmune) may help. If the cause is known, the veterinarian treats that as well.
Corneal Ulcer is a slow-healing sore on or in the dogâs cornea, accompanied by inflammation. Most ulcers are caused by injuries, and treatment often involves antibiotics. Small dog breeds with very short noses and big eyeballs are more prone to eye injuries, says Dr. Samuel J. Vainisi, DVM, ACVO of the Animal Eye Clinic in Denmark, Wisc. âBecause of that, we see a lot of ulcers on the eyes of breeds such as the Boston Terrier, the Pekinese, and the Shih Tzu.â
The most common cause of blindness in dogs, cataract is a clouding of the lens that obscures the dogâs vision. Most dogs with cataracts inherited the tendency to develop them. Inherited cataracts can occur in the Afghan Hound, American Cocker Spaniel, Boston Terrier, Chesapeake Bay Retriever, German Shepherd, Golden Retriever, Labrador Retriever, Miniature Schnauzer, Norwegian Buhund, Old English Sheepdog, Schnauzer, Siberian Husky, Staffordshire Bull Terrier, Standard Poodle, Welsh Springer Spaniel, and West Highland White Terrier. Diabetes, injuries, poor diet and aging can also lead to cataracts.
Surgery is available to treat dogs with cataracts. Removing the lens allows light to again enter the eye. For best post-surgery vision, the natural lens is usually replaced by a plastic lens. âThe surgery itself is not too stressful for the majority of patients,â says Dr. Lim. However, âthe first few weeks postoperatively can be stressful because it is very intensive â the patient must wear an Elizabethan collar at all times, and several medications are required.â
Glaucoma is the elevated pressure of the fluid inside the eyeball caused by fluid draining more slowly than it is produced. Dogs with glaucoma can experience damage to the retina or optic nerve.
Most often, dogs get glaucoma because they inherited an eye structure that leads to poor drainage. Dog breeds in which primary (inherited) glaucoma occurs include the Alaskan Malamute, American Cocker Spaniel, Basset Hound, Beagle, Boston Terrier, Bouvier des Flandres, Chow Chow, Dalmatian, English Cocker Spaniel, English Springer Spaniel, Great Dane, Labrador Retriever, Norwegian Elkhound, Poodle (all sizes), Samoyed, Shar-Pei, Shih Tzu, Siberian Husky, and Welsh Springer Spaniel.Related article
Primary glaucoma has no obvious cause, and it affects both eyes (although one eye may develop glaucoma earlier than the other). Secondary glaucoma is glaucoma that is caused by a dislocated lens, injury, tumor or other problem that decreases fluid drainage in the eye; it may affect just one eye.
Glaucoma treatments include surgery, pills, eye drops or (rarely) removal of the eyeball. âGlaucoma is still one of the more difficult things to handle,â says Dr. Vainisi. âEven though there are literally dozens of glaucoma procedures, there still is not that ideal one ⦠even in humans.â
âProgressive retinal atrophyâ (PRA) is the name for a group of retinal disorders in which rods and cones die off; there is no treatment. Dogs who get PRA do so because theyâve inherited a defective gene. Although PRA strikes more than 100 breeds of dogs, different genes are responsible. Therefore, breeds differ in the age at which the condition appears, how fast the condition progresses, and the ratio of males to females among affected dogs.Â
PRA appears during puppyhood in the Cardigan Welsh Corgi, Cairn Terrier, Collie, Gordon Setter, Great Dane, Irish Setter, Miniature Schnauzer and Norwegian Elkhound. In contrast, some breeds usually donât develop PRA until adulthood. These include the American Cocker Spaniel, English Cocker Spaniel, Labrador Retriever, Lhaso Apso, Miniature Poodle, Portuguese Water Dog, Tibetan Spaniel and Tibetan Terrier. PRA occurs mostly in males in the Siberian Husky and Samoyed. Genetic tests for PRA are available for several breeds.Related article
Other retinal problems include detachment of the retina from the back of the eye, inflammation and abnormal development. Causes include infection and injury. Some retinal disorders have no treatment, while others can be helped by surgery or treatment of the cause.
Small dogs may be more prone to retinal detachment. According to Dr. Vainisi, several small breeds of dogs, including Boston Terriers, Jack Russell Terriers and Shih Tzus, love to pick up toys and shake them hard. âFluid goes violently back and forth in the back of the eye, and it just rips the retina right off,â he says. âOne moment theyâre seeing, and the next moment they can be totally blind.âRelated article
Just like your doctor would refer to you a specialist for expert care for a complicated issue, your vet may do the same for your dog.