Dog Cataracts

Brown and white fluffy dog with cataracts

Cataracts can affect your dog’s sight and can sometimes even cause pain. So, what are cataracts, and what causes them? And, if your dog does develop cataracts, how much will their lives be affected?

What are cataracts?

In a healthy eye, light passes through the lens and focuses on the retina at the back of the eye. This allows your dog to see. But light can only travel through the lens if it is transparent. When a cataract is present, the lens becomes cloudy or opaque and can block light from passing through to the back of the eye, interfering with sight.

What causes cataracts in dogs?

There are many reasons why your dog might form cataracts in one or both eyes. Sometimes, your dog will show other symptoms, which might give you a prior warning. In contrast, a cataract can also develop without any other illness. Causes include:


Cataracts can be common in some breeds. This doesn’t necessarily mean that your dog will have been born with cataracts, nor that they will develop them when they are young. However, it does mean that they are more likely to develop them during their lifetime. Often, they will develop cataracts in both eyes, but not necessarily simultaneously. Some breeds commonly affected by inherited cataracts include Labradors, Golden Retrievers, Miniature Schnauzers, Poodles, Boston Terriers, Springer Spaniels, and West Highland White Terriers.

Diabetes Mellitus

Diabetes is one of the leading secondary causes of acquired cataracts. When dogs are diabetic, they don’t have enough insulin to lower their blood sugar. This causes persistently high blood sugar levels, and in turn, sugar levels within the body tissues become high. One of these body tissues is the lens in the eye itself. The increased sugar within the lens draws water in by osmosis, leading to cataract formation. Occasionally, sudden onset blindness due to cataracts is the first symptom of diabetes. Still, it’s much more common to see an increase in thirst and urination, weight loss, vomiting, or reduced appetite.

Older age

Older dogs can develop cataracts as part of aging, with no underlying condition or genetic cause.


Examples of toxins that can cause cataract formation include the antifungal medication Ketoconazole and the wormer Disophenol.

Eye inflammation

Eye inflammation due to trauma, uveitis, or glaucoma can lead to cataract development either because the inflammation itself affects the lens or due to free radical formation.

Other causes

Rarely cataracts can also be caused by nutritional imbalances. This occurs in puppies who receive certain milk replacers due to a deficiency in amino acids. Conditions that affect the parathyroid gland or cause low calcium levels also can cause cataracts, but again this is rare.

What are the signs of cataracts in dogs?

Your first indication that your canine companion has, or is going to develop cataracts, could be a symptom of the underlying cause. For example, if your dog has Diabetes Mellitus, you might notice that they are particularly thirsty or that they have to pass urine often. If they have glaucoma, they might show signs of eye pain, like being head shy, squinting, or even showing aggression.

If the cataract is not secondary to another health condition, you won’t spot signs until the cataract begins to form. The symptoms will depend on whether one or both eyes are affected. 

Signs of a cataract in one eye

If your dog starts to develop a cataract in just one of its eyes, you’re unlikely to notice much change in its vision until much later. While the cataract is immature, dogs tend to cope very well. They should see enough to navigate around most obstacles without any telltale bumps or stumbling. Therefore, it’s very common not to notice that your dog has a cataract until it’s mature enough to cause a white, cloudy effect in the center of their eye.

Signs of cataracts in both eyes

If your dog begins to get cataract formation in both eyes, you’re more likely to notice changes in their vision at an earlier stage. This could start with night blindness or your canine companion seeming more tentative when walking at dusk or dawn. You might also notice them jump as if suddenly seeing you even though you have approached them slowly. As their cataracts progress, they might start to seem more clumsy by tripping or walking into things. As cataracts become more mature, they will become more visible within the eye itself. Therefore, if they are quick to develop, your first indication might still be the sudden cloudiness of their eye.

Are dog cataracts painful?

Cataracts are not usually painful, although the underlying cause can be painful. Examples of painful conditions that cause cataracts include trauma, uveitis, or glaucoma. However, sometimes when a cataract progresses and becomes hyper-mature, it can cause the lens to break down. These changes in the lens can lead to inflammation or glaucoma and can even cause the lens to prolapse into the front chamber of the eye. These conditions can be intensely painful. Sadly, there are fewer treatment options when a cataract has become hyper-mature and causes secondary eye pain.

Can my dog live with cataracts?

Not all cataracts will develop at the same rate, and many will stop progressing before becoming hyper-mature. So, not all cataracts will become painful if left untreated, but some underlying causes will make pain more likely. If your dog has a single cataract, and it remains small and immature, it’s unlikely to cause pain and may only have a subtle impact on their ability to see. Therefore, it’s perfectly plausible that they could live with this cataract and continue to have a good quality of life.

If your dog has cataracts in both eyes, it’s far more likely to affect their vision, and if the cataracts are mature, they may go completely blind. If your dog loses their sight, it can be very distressing for you, as a pet parent, and it’s natural to assume that your dog’s quality of life will suffer without its vision. However, although some dogs don’t cope well with blindness, others can cope very well. This is especially true if cataracts mature slowly because your dog has more time to adapt to gradual sight loss.

Unfortunately, if your dog’s cataract causes glaucoma, inflammation, or lens prolapse (lens luxation), it can cause your dog severe pain and suffering. Because these conditions usually occur in hyper-mature cataracts, cataract surgery is rarely an option. Your veterinarian can talk you through the treatment options that can help your dog feel better, but an operation to remove the eye is often needed.

How are cataracts treated in dogs?

The treatment options available for cataracts will depend on the cataract’s stage of development. In terms of ease of treatment and success rate, the earlier the cataract is treated, the better.

Specialist eye veterinarians perform cataract treatments, and the techniques used usually rely on removing the lens itself.

For early cataracts, the lens is usually removed by a process called phacoemulsification. With this technique, the lens is broken down by ultrasound waves and removed from the eye through a small incision. However, this treatment method is most appropriate for the early stages of cataracts and is less often used if the lens has luxated.

For cataract treatment to succeed, any underlying conditions, like diabetes, should be stabilized first. However, following cataract surgery, aftercare, usually in the form of eye drops, is equally as essential to ensure a good recovery.

What happens if you leave cataracts untreated?

Cataracts left untreated will often become more prominent, involving more of the lens over time. As it progresses, your dog’s vision will gradually become more affected. When no light can pass through the lens to the back of the eye, your dog will become blind, either in one eye or both. In some cases, the cataract will begin to cause the lens to break down. This can lead to painful complications like glaucoma, uveitis, or a luxated lens.

What else can cause your dog’s eyes to look cloudy?

Cataracts are probably the most well-known cause of cloudy eyes among pet dogs. So, it’s understandable if, when you spot a white hue in your dog’s eye, you automatically assume it’s a cataract. But the truth is there are a few other causes of cloudy eyes when it comes to canines. Your veterinarian will be able to use various tools, including a light source and ophthalmoscope, to examine your furry friend’s eye. This will help them assess whether your dog has cataracts or another cause for the cloudiness.

Nuclear Sclerosis

Nuclear Sclerosis is very common in older dogs and can easily be confused with cataracts. In dogs with Nuclear Sclerosis, their lens becomes bluish due to old age change, but the dog’s vision is not affected.

Lipid deposits

Lipid or fat deposits on the surface layer of the eye can look like tiny white blobs. They are common in Cavalier King Charles Spaniels and do not affect vision.


Previous trauma to the eye can cause the cornea (the surface) of the eye to become scarred. These scars can vary in color from black to white. Although severe cornea scarring can distort your dog’s vision, they do not affect the lens and should not be confused with cataracts.

So, what should you do if you suspect your dog might have cataracts?

If you’ve noticed your dog’s behavior has changed and you’re worried they can’t see as well as they used to, you might suspect cataracts. Similarly, you might have noticed that their eyes appear cloudy or white. So if you’re concerned that your dog might have cataracts, the best thing to do is to book an appointment with a veterinarian, especially if you think they might be in pain. Cataracts can be treated and your dog’s vision restored, but only if the cataract is at an appropriate stage of development.

Don’t forget that your veterinarian will check your canine companion’s eyes at every wellness exam. Still, you should always mention it if you have concerns. If your dog does develop cataracts, and you choose not to go ahead with surgery, your dog may cope well with reduced sight. But it would be best if you watched them closely for any signs that their eye is painful. With regular check-ups, your veterinarian will be able to help you ensure that your pup goes on to have an excellent quality of life, with or without cataracts.