Cloudy Eyes in Dogs: Causes, Symptoms, and Treatments

Developed in collaboration with Rustin Sturgeon, DVM, DACVO | National Medical Director of Ophthalmology | Pathway Vet Alliance

Last reviewed: February 23, 2024

Cloudiness or haze in a dog's eyes can stem from multiple medical causes. Some of these are benign, pain-free, and easy to treat. Other symptoms may cause discomfort and need immediate intervention. So, to treat cloudy eyes in dogs, you need a correct diagnosis from your veterinarian.

What To Look For

Look for a hazy, cloudy appearance in one or both eyes. It may seem nearly solid or opaque (that is, not transparent or clear). Take note of the color, location within the eye, onset, and additional symptoms. These factors can provide some clues about the underlying cause of the cloudiness.

Diagnosing the Causes of Cloudy Eyes

To uncover the root cause of your pet's cloudy eyes, your veterinarian may run one or more of the following tests:

• Schirmer Tear Test (STT): This test measures tear production and is particularly useful for pets that may have dry eye or an excess of tears.
• Fluorescein Stain Test: This test uses orange dye (fluorescein) and blue light to find foreign objects in the eye and detect damage to the cornea. 
• Tonometry: This test measures pressure inside the eyes. It is used to screen for glaucoma and check the effectiveness of glaucoma treatments.

These tests typically do not cause your pet any discomfort – in fact, you may have had one or more of these tests done at your last eye exam. Based on the results, your veterinarian can tailor a medication regimen for the diagnosed condition.

Common Conditions That Cause Cloudy Eyes

Keratoconjunctivitis Sicca (KCS) Or “Dry Eye”
KCS is commonly known as "dry eye." It is a painful condition caused by the lack of tear production. Tears are important for keeping eyes lubricated. If not enough is produced, eyes can become dry, itchy, and seem cloudy. This can also lead to blurred and troubled vision.

Typical symptoms of “dry eye”:

• Frequent eye rubbing, 
• swelling around the eyes, 
• redness inside the eye (like pink eye in humans), and 
• a milky-stringy discharge, or excessive blinking.

Corneal Dystrophy
Corneal dystrophy describes conditions that cause the corneas to become white, cloudy, and opaque from minerals, cholesterol, or a combination of both. The size, shape, and density of the areas of deposits vary. The areas can be noticeable but rarely cause blindness.

Certain breeds, like the Shetland sheepdog, Siberian husky, beagle, American cocker spaniel, miniature schnauzer, and Airedale terrier, have a genetic predisposition to corneal dystrophy. Corneal dystrophy affects both eyes and occurs in dogs of any age. Your veterinarian may perform routine blood work to check for elevated levels of cholesterol or calcium in the blood.

Corneal dystrophy falls into three main categories: epithelial, stromal, and endothelial. Each of these categories relates to the part of the cornea where the cloudiness occurs, whether it is the outer, middle, or innermost layer.

• Epithelial Corneal Dystrophy: In this form, cloudiness occurs on the cornea's outer surface layer. It's common in many dog breeds. While most dogs experience no symptoms beyond corneal opacity, some may suffer from pain and light sensitivity.
• Stromal Corneal Dystrophy: Cloudiness happens in the stroma, the cornea's middle layer, and generally appears in a pattern. The most common are gray, white, or silver opacities near or at the cornea's center or a ring around the cornea's outer edge. In some cases, the whole cornea becomes cloudy, affecting vision. This condition generally arises in younger dogs and typically presents no additional symptoms.
• Endothelial Corneal Dystrophy: This condition affects the cornea's deepest layer and might progress or not. More severe cases can lead to endothelial degeneration, potentially resulting in corneal edema.

In some cases, corneal dystrophy might advance to corneal degeneration. This can lead to the development of corneal scarring and vascularization. In more severe cases, corneal ulcers may form due to the shedding of mineral deposits.

Corneal Ulcers
The cornea is the clear, glossy "window" at the front of the eyeball. A scratch from another animal, a cut from a sharp object, or a chemical burn from soap or shampoo in the eye commonly cause corneal ulcers.

Sometimes, bacterial or viral infections or another eye disease can complicate a corneal ulcer. For instance, a dog with dry eye (see KCS above) often experiences secondary corneal ulcers.

If your dog has a corneal ulcer, it may blink or squint more due to pain. You may also notice cloudiness, redness, tearing, and a brownish-green discharge from the eye.

Anterior Uveitis
Uveitis refers to the inflammation of parts of the uvea – the iris, the ciliary body, and the choroid. The iris is the colored part of the eye, with a hole in the middle that forms the pupil. Behind the iris is the ciliary body, the fluid factory of the eye. It produces a secretion known as aqueous humor. The choroid is the base layer of blood vessels under the retina, tasked with keeping it healthy.

This condition can be painful, cause blindness, and either be a primary issue or a symptom of another underlying problem. Your veterinarian will perform a physical exam and run tests to understand its specific type.

The signs of uveitis include eye redness, cloudiness, consistent rubbing, swelling, discharge, and changes in vision. Many dogs experience discomfort, which may worsen into pain. Most affected dogs tend to avoid bright lights or keep their eye closed.

Glaucoma in Dogs
Glaucoma affects dogs when their eye pressure rises, leading to a complex, advancing, and often painful eye disorder. It inflicts irreparable damage to the optic nerve and retina, causing blindness.

The signs of glaucoma range from a protruding eye bearing a red or blue hue to cloudiness, a watery discharge, an enlarged pupil, redness, irritation, and sight loss. If you suspect increased pressure in your dog's eye, it's a veterinary emergency—contact your vet immediately.

Glaucoma in dogs comes in two types:
Primary glaucoma affects many breeds of dogs. Check with the American Kennel Club for a PDF of the full list of breeds genetically predisposed to glaucoma. 
Secondary glaucoma is typically caused by a specific medical condition like uveitis, cancer or tumors, cataracts, a shifted lens, or a detached retina.

Your veterinarian can determine if your pet’s glaucoma is primary or secondary. Treatment for each type is different, and for secondary glaucoma may include treating an underlying medical condition.

Nuclear Sclerosis
As dogs age, some eye cloudiness is normal. The most common cause is a condition called nuclear sclerosis, also known as lenticular sclerosis. Many dog owners often confuse this with cataracts.

Nuclear sclerosis happens when the central lens of your dog's eye hardens over time. This hardening occurs due to continuous growth of the eye's outer lens cortex as the dog ages. As a result, the eye gets a cloudy look, much like what we see in cataracts.

Nuclear sclerosis is the natural hardening of the central lens resulting from compression by the lifelong growth of the outer lens cortex of your dog’s eye as it ages. This creates a cloudy appearance similar to cataracts.

Cataracts
Cataracts are a common cause of cloudy eyes, especially in older dogs. Cataracts in dogs occur in the same way as in humans. They happen when proteins cluster in the eye's lens, creating a bluish, cloudy barrier. This barrier prevents light from getting to the dog's retina. This, in turn, causes obscured vision and can potentially lead to blindness.

The breed and age of a dog can affect cataract formation. However, other causes such as diabetes, eye injury, and malnutrition can also contribute. Your veterinarian may perform blood tests to diagnose some conditions causing cataracts. Go to the American Kennel Club for a PDF of the complete list of breeds susceptible to cataracts.

Corneal Degeneration
The innermost layer of the cornea, called the endothelium, can break down due to a condition called corneal degeneration. This single cell layer lining the cornea has an inability to regenerate or repair itself. The job of the endothelium is to stop fluid from inside the eye from being absorbed by the stroma, and the stroma is the middle layer of the cornea.

One or both eyes can be affected by corneal degeneration, and it may impact areas of the cornea damaged by prior trauma or chronic illnesses. When the endothelium fails or degenerates, the stromal layer absorbs and retains too much fluid. This causes the cornea to take on a blue, cloudy look.

The blue cloudiness can appear anywhere within the cornea. The degeneration might not show any obvious signs in its early stages. As the condition worsens, the swelling may cover a larger area of the cornea. The rate at which this happens can vary.

Vision impairment may increase as the condition worsens, and it might cause total vision loss. Dogs with this condition may also develop corneal ulcers. The condition is more prevalent in middle-aged or older Boston Terriers, Chihuahuas, and Dachshunds.

Your veterinarian may prescribe a customized, compounded medication. These medications are mixed by trained, licensed compounding pharmacists and often come in dosage forms designed to make giving or applying the medication easier and more accurate.

Treatments for cloudy eyes

Veterinarians decide the dose of your dog's topical or oral medicine. They base this on your dog's weight, age, condition, level of discomfort, and any current illnesses. They may also recommend eye surgery or, if the condition is serious enough, removing the eye.

Next, they will create a treatment plan for your dog's cloudy eyes if needed. So, make sure to adhere to the prescribed dosage and application. If the condition is complex and difficult to handle, they may suggest visiting a veterinary ophthalmologist. You can find an ophthalmologist near you with the help of the American College of Veterinary Ophthalmologists by visiting their website ACVO.org.

Keratoconjunctivitis (KCS) or “dry eye”: Generally, veterinarians manage dry eye with topical medication containing cyclosporine or tacrolimus. Chronic KCS, however, if left untreated, can cause corneal scarring, and recurrent corneal ulcers both of which can lead to blindness. Chronic KCS, however, if left untreated, can cause corneal scarring, and recurrent corneal ulcers both of which can lead to blindness.

Corneal dystrophy: Corneal dystrophies usually don't cause vision problems in dogs. So, unless another underlying condition is causing it, dogs don't typically require treatment.

Corneal Ulcers: Corneal ulcerations are managed depending on the cause being associated with mineralization. Some Wedgewood Pharmacy topical medications such as cyclosporine, tacrolimus, or edetate disodium ophthalmic. 

Anterior uveitis: When dealing with this condition, veterinarians typically aim to reduce inflammation. 
The first step is to figure out if the issue is a primary condition or a result of something else, like an infection, parasites, cancer, or an autoimmune disease. Generally, treatment includes using a medication you put directly on the eye, like prednisone, in addition to a drug you take by mouth, such as methazolamide.

Glaucoma: There are a number of treatment options for glaucoma, depending on how severe it is and how far it has progressed. Typically, veterinarians prescribe a mix of topical and oral medications. For instance, they might suggest drugs like methazolamide to help control eye pressure. They may also recommend applying demecarium bromide ophthalmic solution to the eye to reduce pain and discomfort.

If the case is severe or if the disease has progressed quite a bit, medical treatment might involve surgery to reduce eye pressure. If your pet has become blind or doesn't respond well to the treatments, the veterinarian may consider removing the eye.

Nuclear Sclerosis: Nuclear sclerosis is a product of age, does not cause pain, discomfort, or additional symptoms. It requires no treatment.

Cataracts: Surgery is the standard treatment for cataracts in dogs and has a high rate of success and a good prognosis.

Corneal Degeneration: Unfortunately, this condition cannot be reversed. However, an initial treatment typically involves using a non-irritating salt ointment, known as a topical hyperosmotic. This ointment can help remove excess fluid from the cornea stroma. To prevent the disease from worsening, veterinary ophthalmologists might suggest surgery.

When to Contact Your Veterinarian

There are many reasons for your dog’s cloudy eyes – some are serious and need immediate attention, others not so serious – it is difficult to tell the difference. That is why you should consult your veterinarian as soon as you notice signs and symptoms that there is a problem with your dog’s eyes or vision.

If you notice things like cloudy, opaque eyes, redness, increased discharge, discomfort or irritation, or changes in shape, color, size, or vision, contact your veterinarian immediately.

Compounded Treatments

Your veterinarian may prescribe a customized, compounded medication. These medications are mixed by trained, licensed compounding pharmacists and often come in dosage forms designed to make giving or applying the medication easier and more accurate. Visit the Wedgewood Pharmacy Medications page for a complete list of compounded medications available.

Article Summary

Common Symptoms

• May include pain, itchiness, swelling, redness in or around the eye, discharge, excessive tearing, bulging, sensitivity to light, excessive blinking or squinting, vision changes or loss.
• Opaque (not see through) white or grayish appearance.
• Blue or red hazy appearance.
• Cloudiness over entire eye, in one spot in the eye, or in the lens.
• May be a sudden change or a gradual change over time.

Common Causes 

• keratoconjunctivitis sicca (KCS) or “dry eye”
• corneal dystrophy 
• corneal ulcers 
• anterior uveitis 
• glaucoma 
• nuclear sclerosis
• cataracts
• corneal degeneration

Tests & Diagnosis

• Schirmer Tear Test (STT)
• Fluorescein Stain Test
• Tonometry
• Blood tests to look for underlying causes.

Common Treatments

• Some conditions require no treatment.
• Veterinarians prescribe a specific topical or oral medication dosage based on your dog’s weight, age, the stage of the condition, the level of discomfort, and to manage any underlying diseases or causes.
• Veterinarians may prescribe customized, compounded medication mixed by trained, licensed compounding pharmacists and often come in dosage forms designed to make giving or applying the medication easier and more accurate.

Frequently Asked Questions

Sources

This article is meant to provide general and not medical advice. We strongly recommend that a veterinarian be consulted with for the specific medical needs of your animal.

Sources:

American Kennel Club
VCA Animal Hospitals