If the eyes are the windows to the soul, then it is no wonder we get worried when our dog's eyes start getting cloudy. After all, we don't want our dogs to lose their vision or be uncomfortable.
As with people, when dogs have cloudy eyes it may be a natural part of the aging process. Other times, cloudy eyes could be a symptom of a number of eye problems. Trying to distinguish between what is normal and what is a problem can be tricky. While your veterinarian is your best source of information about your dog's eye health, it does help to know what types of eye problems can cause a cloudy appearance in your dog's eyes, and any other symptoms you can look out for.
The most common causes of cloudy eyes in dogs are nuclear sclerosis and cataracts. However, there are some other conditions that can also create a cloudy appearance in your dog's eyes that require immediate veterinary attention.
Nuclear Sclerosis in Dogs
As dogs age, some cloudiness is normal. “Most dogs, with age, develop a haze within the lens, similar to cataracts, called nuclear sclerosis,” says veterinary ophthalmologist Martin Coster, DVM, MS, DACVO. “Unlike cataracts," Coster goes on to say, "this condition rarely causes vision impairment. However, focusing ability may become impaired.”
It is easy to confuse cataracts and nuclear sclerosis. Both conditions cause the lens to appear cloudy, but there are a few differences. Nuclear sclerosis usually gives your dog's eyes a cloudy, bluish discoloration, unlike cataracts, which are white and opaque.
More important, nuclear sclerosis does not diminish your dog's vision the way cataracts do. It tends to affect both eyes at the same time, and the two conditions look different to your veterinarian when he or she examines your dog's eyes with a special tool.
There is no treatment for nuclear sclerosis, as the condition does not cause serious problems, but it might be a good idea to discuss your dog's aging eyes with your veterinarian, so that you know what to expect, as your dog grows older.
Nuclear sclerosis is very common, and while it is not a major cause for concern, there are other causes of cloudy lenses that can result in more serious problems that you may want to rule out with your veterinarian.
Cataracts in Dogs
Dogs develop cataracts just like people do. These white, milky changes to your dog's lens are the result of abnormal lens metabolism. The lens in both dog eyes and human eyes acts like a camera lens, focusing light on the film at the back of the eye, called the retina, where the brain then processes the information to form a picture of the world around it.
The lens is made up of water and protein. These materials are organized in a very specific way, and when the proteins start to clump together, either as the result of age or trauma, they can form cataracts. These 888protein strands gradually obscure the lens, making it harder for your dog to see.
There are a variety of causes of cataracts in dogs, including age, trauma, metabolic diseases such as diabetes, and genetics.
Some breeds of dog are more susceptible to inherited cataracts than others. These cataracts can occur when the dogs are puppies or as they age, depending on the type of inherited cataracts. Breeds most commonly affected include the Bichon Frise, Boston Terrier, Poodle, Cocker Spaniel, German Shepherd Dog, Golden Retriever, Labrador Retriever, Siberian Husky, and West Highland White Terrier, just to name a few.
Some cataracts form quickly, like the ones caused by diabetes, while others develop slowly over time, and some, like incipient cataracts, only affect less than 15 percent of the lens.
Cataracts can obscure your dog’s vision. Sometimes they do not pose any additional problems beyond vision loss itself, but other times, they can lead to an even more serious issue: glaucoma.
Glaucoma in Dogs
Glaucoma in dogs occurs when the pressure inside the eye increases, resulting in damage to the structures in the eye. This condition is painful, and very high intraocular (inside the eyes) pressures are considered a veterinary emergency, as they can lead to permanent loss of vision.
There are two types of glaucoma: primary or inherited glaucoma, and secondary glaucoma, which is usually caused by another condition such as cataracts, a lens luxation or subluxation (where the lens shifts position in the eye), cancer, inflammation, or retinal detachment.
Inherited glaucoma affects several breeds of dogs, including the Beagle, the English Cocker Spaniel, Chow Chow, Basset Hound, Russell Terrier, Chinese Shar-Pei, and Arctic Circle breeds such as the Siberian Husky and the Norwegian Elkhound. These are just a handful of breeds impacted by inherited glaucoma, though.
A cloudy eye is not the only symptom of glaucoma. You may also notice that the white of the eye is red and irritated, or that there is a bulge to the eye, a blue or red tint to the cloudiness, increased discharge, squinting, and most alarmingly, loss of vision.
If your dog has any of these symptoms, contact your veterinarian immediately.
Glaucoma is usually diagnosed with a tool called a tonometer, which measures eye pressure, and the condition is treated with ophthalmic medications. In severe cases, a surgical procedure may be necessary to address the cause of the secondary glaucoma or to make your dog more comfortable.
In cases where medication fails, your veterinarian may recommend laser therapy, eye removal, implants to facilitate drainage, gentamicin injections, evisceration and prosthesis, and cyclocryotherapy (a procedure used to reduce the production of intraocular fluid.) Talk to your veterinarian about the best option for your dog.
Dry Eye in Dogs
Some cloudy eyes look like they have actual clouds in the lens, while others might look like there is something on the surface of your dog’s eye clouding it up. Severe cases of dry eye can lead to corneal ulceration and scarring, which falls into the second category.
Dry eye, or keratoconjunctivitis sicca, occurs when your dog’s body does not produce enough tears. Tears are necessary for lubrication and overall eye health, as the aqueous solution is how your dog’s eyes receive necessary nutrients.
When your dog is not producing enough tears, the surface of her eyes becomes irritated. Ulcers can form, and in severe cases lead to perforation of the eye itself. In chronic cases of dry eye, the surface can scar, creating a cloudy, dull appearance.
There are other symptoms of dry eye besides cloudy eyes. These include mucous discharge, redness around the whites of the eye, and squinting or excessive blinking. Dry eye is often associated with an autoimmune inflammation of the tear glands and can be a chronic, lifelong condition.
Luckily, dry eye can usually be treated with tear stimulating medications, and in severe cases there are surgical options available to help promote increased tear production.
Ulcers in Dogs
Ulcers that form as a result of dry eye, trauma, or other ophthalmic problems, like entropion (inward folding eyelids) or distichia (problematically placed hairs), can also create a cloudy appearance in your dog's eye.
Ulcers are sores on your dog’s cornea. As they progress, they may appear bluish, reddish, or just as a haze on the surface of your dog’s eye. Like other serious eye problems, they are often accompanied by discharge and squinting, and if they become infected they can lead to severe damage and even perforation.
Ulcers are usually treated with medicated drops, and in severe cases may require surgery to save your dog’s eye, so it is best to get your dog in to see the veterinarian as soon as you notice signs of ocular discomfort, like squinting or rubbing at the eye with a paw.
Anterior Uveitis in Dogs
Anterior uveitis can also cause a cloudy appearance in your dog’s eyes. The uvea refers to the part of the eye that is made up of the choroid, ciliary body, and iris— the tissue at the front of the eye, for those of you who don't have a anatomical model of the eye on hand. Anterior uveitis is inflammation of one or all of these structures, and it is a serious condition that can lead to irreversible vision loss.
Symptoms of anterior uveitis include redness, discharge, squinting, an oddly shaped pupil, eyeball swelling, excessive tearing, and a cloudy or dull appearance. This painful condition can have a number of causes, including autoimmune disease, cancer, trauma, metabolic disease, parasites, and fungal, viral, and bacterial infections, and your veterinarian may run a series of diagnostic tests to narrow down the culprit. Treatment will depend on the cause, and could include eye drops, eye ointments, and oral medications.
Corneal Distrophy in Dogs
Some dogs develop a condition called corneal dystrophy, which gives their cornea an opaque, cloudy appearance. This condition is inherited, and is broken down into three types depending on the location: epithelial, stromal, and endothelial.
Epithelial corneal dystrophy affects the superficial layers of the cornea. This condition can be uncomfortable, and Shetland Sheepdogs appear to be the most susceptible breed.
Endothelial corneal dystrophy affects the deepest corneal layer. Dogs with this condition are typically older, and Boston Terriers, Chihuahuas, and Dachshunds are genetically predisposed. This type of dystrophy can lead to corneal ulcers.
Epithelial and endothelial cornea dystrophy can both cause ulcers that require treatment, but there is no cure for corneal dystrophy. Luckily, this condition usually does not lead to compromised vision.
Diagnosing Cloudy Eyes in Dogs
A veterinarian is the best person to diagnose the cause of your dog's cloudy eyes, and your general practice doctor may refer you to a specialist in veterinary ophthalmology for further treatment.
Veterinarians usually diagnose eye problems in dogs through an ophthalmic exam. Your veterinarian may look into your dog’s eyes using specialized tools and may also perform a series of tests to establish your dog’s overall eye health. These tests can include a Schirmer tear test, which measures your dog’s tear production; a fluorescein stain, which looks for abnormalities like ulcers on the surface of your dog’s eyes; and a tonometry reading to check your dog’s eye pressure.
Based on these findings and your dog’s symptoms, your veterinarian will be able to give you an answer or refer you elsewhere for further diagnostics.
Treating Cloudy Eyes in Dogs
The treatment for your dog’s cloudy eyes depends on the cause. Nuclear sclerosis, for example, is a natural aging process that has no cure, while cataracts can be removed with cataract surgery. Your veterinarian will lay out a plan to treat your dog’s cloudy eyes if he or she feels treatment is necessary.
Watch your dog closely for other symptoms of eye problems, such as increased discharge, squinting, or a change in your dog’s eyes shape, size, color, or vision, and contact your veterinarian as soon as possible if you notice redness, squinting, or thick discharge from your dog's eye, in addition to cloudiness.