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What are possible causes of cloudy eyes in dogs?

Cloudy eyes in dogs can be associated with different eye problems, or it can just be a sign of your dog aging.

In most cases, it is linked to a natural aging process in middle-aged to senior dogs (typically over six years of age). 

In some cases, the condition can be painful and challenging to treat.

In the worst cases, it can cause your dog to experience pain and vision loss.

Apart from changes to the lens, cloudy eyes in dogs can be caused by fat and calcium deposits in various parts of the cornea, lens and retina, a relatively normal process. It can also be a result of an accumulation of protein, white blood cells, inflammation, or the presence of genetically-linked defects. 

Other common causes of cloudy eyes include:

Lenticular Sclerosis

Lenticular sclerosis (or nuclear sclerosis) is a common and painless condition , that  is a normal change associated with aging. It occurs when the fibers in the lens of the eye become older and less flexible, resulting in a bluish, transparent haze that you can see best when looking at your dog from the side of their face.

It can appear as a “cloudy” discoloration on the pupil, and typically occurs in both eyes symmetrically. Luckily, it does not seem to significantly affect a dog’s vision. 

Although some senior dogs do end up developing age-related cataracts after having lenticular sclerosis, there does not appear to be a causal relationship between the two.

Lenticular sclerosis is a common and painless condition associated with aging.

Pro Tip: Look at your dog from the side of their face to best identify lenticular sclerosis.


One of the most common causes of eye issues in dogs is a scratch to the lens of their eye. Injuries to the eyes and head can cause scarring or blindness, and can result from several different situations including:

  • Being scratched in the eye when playing with another animal or human.
  • Being hit in the head by blunt force i.e. a rock. 
  • Rubbing their eye(s) on a rough surface, such as carpet or the ground (this may also be one of the signs your dog is exhibiting after their eye gets scratched, in an attempt to relieve the discomfort or pain).
  • Scratching at their eyes when there is debris on their lens (i.e. sand, toxins or chemicals).
  • Running off leash through dense bushes, forests or very sandy areas.

In more severe cases of trauma to the eye, deep abrasions to layers of the cornea can lead to corneal ulcers, a very painful condition. Most dogs will rub the affected eye(s) with a paw or on the ground to try and relieve the pain, and there may be a discharge from the eye(s).

Pro Tip: Look out for your dog rubbing the affected eye(s) with a paw or on the ground. They are trying to relieve the pain.


Canine cataracts occur when the inside of the lens becomes cloudy due to the breaking down of proteins. Cataracts can partially or completely block light from passing through, and vision cannot be processed. Most dogs with cataracts can still see shapes and shadows, but it is like looking through a frosted window or a muddy windshield. 

Cataracts are often characterized by cloudiness just beyond the pupils (the hole in the center of the iris), but it is easy for pet parents to mistake nuclear sclerosis (a normal change in the lens associated with aging) for cataracts.

With a thorough eye exam, your veterinarian will be able to distinguish the difference. If your dog tends to bump into things, however, it is likely that he is developing cataracts. 

Age is not the only inciting factor for cataracts: hereditary diseases and the development of diabetes can also cause cataracts. Endocrine problems like diabetes can occur in middle-aged dogs, and hereditary diseases can affect very young puppies in some cases.  

Cataracts are caused by proteins being degraded, and will impact your dog’s vision

Pro Tip: If your dog tends to bump into things, they are likely developing cataracts.

Dry Eyes

Dry eyes occur when the tear glands of one or both eyes do not produce enough tears to produce a protective film over the corneas. While some cloudy eyes look like there are actual clouds inside the eyes, some appear as if something is covering the eye. Since tears are essential for overall eye health, insufficient tear production also affects how the eye receives nutrients. 

Dry eyes can become very itchy and irritated, and they can develop ulcers due to lack of protection. In severe cases, it can cause pain, scarring and vision loss. While some cases of dry eye are due to an immune-mediated condition, breeds like Pugs and Yorkshire Terriers are more susceptible to developing it. 

Other dry eye symptoms include:

  • Redness around the whites of the eyes
  • Mucus discharge
  • Excessive blinking
  • Squinting
  • Swelling on the eye surface tissue

Dry eye is almost always a lifelong medical issue. If pets do not respond to antibiotics, lubricants and topical eye medications to help stimulate tear production, eye surgery may be necessary for severe cases. 

Corneal Ulcers

Corneal ulcers are a very painful condition, and need immediate medical attention. 

Ulcers on the eye are usually a result of trauma to the eye or eyelids, rubbing of the eyes due to an eyelash or other foreign object in the eye, and severe cases of dry eye. 

Sometimes there is also a discharge from the eye(s) and dogs will often squint, with tearing and redness in the eyes. If left untreated, corneal ulcers can enlarge and even cause the eyeball to rupture.

Corneal ulcers in a dog. Please note the green stain is a tool used to visualize the ulcers - your dog’s eyes won’t turn green from ulcers!


Glaucoma is another eye condition that can cause cloudy eyes in dogs. It occurs when fluids in the eye do not drain properly, causing a continuous and gradual buildup that ultimately increases pressure in the eye. This pressure damages the eye’s internal structures, and can lead to permanent vision loss if left untreated for long.

Glaucoma is a medical emergency that is painful for dogs. Primary glaucoma is often inherited genetically, while secondary glaucoma can be caused by other conditions like cataracts, trauma, inflammation and cancer.

Primary glaucoma affects different dog breeds and is not always avoidable. Secondary glaucoma, however, may be avoided since it is caused by another eye condition. Early intervention is key. 

Glaucoma symptoms are not always a cloudy eye. Sometimes, you may notice a bulge in the eye or the whites of the eye may be red and irritated. Apart from this, there may be a red or blue tint to the cloudiness, squinting in one or both eyes, a dilated pupil, or increased discharge.


Uveitis is the medical term for inflammation of the uveal tract, a layer of tissue in the eye that contains  the iris. When the uveal tract is inflamed, it can make the eye appear red, cloudy, and increase tearing and sensitivity to light. 

If the uvea or any associated structure is inflamed, it can cause irreversible vision loss if left untreated. Other symptoms may include eyeball swelling, squinting, and eye discharge.

Uveitis is usually a secondary condition caused by another underlying issue including infections, trauma, metabolic or autoimmune diseases and cancer. 

Uveitis in dogs will typically present as redness, eye discharge, squinting or swelling.

Pro Tip: Any eye issues in dogs are almost always an emergency, if not very urgent. It’s important to see your veterinarian as soon as possible to prevent any permanent damage to the eye.