Cataracts are a common cause of vision loss in our canine companions, and sadly, can lead to complete blindness. But what are cataracts? And what can we do about them?
What are cataracts?
In a healthy eye, light passes in through the cornea (the surface at the front of the eye), through the lens, and to the retina at the back of the eye. For a dog to have normal vision, the lens needs to be transparent (clear).
A cataract means there is an opacity in the lens of the eye. This interferes with the normal passage of light from the front to the back of the eye, meaning that vision is reduced.
What are the symptoms of cataracts?
You may have noticed that your dog has a cloudy or grey tinge to his eyes. In the early stages, you may only see this at certain angles or in photographs. Perhaps you have noticed that your dog seems to have reduced vision, especially in low lighting. It may be that your dog has cataracts.
However, a cloudy eye does not always mean there is a cataract. For example, nuclear sclerosis looks similar to cataracts and causes a bluish haze to the eye. However, this is a normal aging change and doesn’t affect vision unless it is very severe.
If you suspect cataracts, try not to worry. Contact your veterinarian who will be able to guide you about whether or not your dog has a cataract.
What Causes Cataracts In Dogs?
There are two main types of cataracts – primary and secondary cataracts.
Primary cataracts develop on their own without an underlying health condition. There is usually a genetic cause for these cataracts, and dogs may be born with them (congenital cataracts). Some breeds are at particularly high risk of cataracts, such as Golden Retrievers, Miniature Schnauzers, West Highland White Terriers, and Old English Sheep Dogs.
Secondary cataracts are caused by damage or inflammation to the eye. This type of cataract often affects older dogs. Causes of secondary cataracts include:
Age: as animals get older, the lens degenerates, and cataracts form. These are often called ‘senile cataracts’ and usually cause a gradual loss of vision.
Diabetes mellitus: most dogs suffering from diabetes will develop cataracts, even if they are in treatment for the disease. In dogs with diabetes, the amount of sugar in the blood becomes excessively high. This means that sugars then enter the lens, which draws more fluid into the lens, leading to cataract development. and cataracts develop. These types of cataracts tend to progress quickly.
Trauma to the eye: injuries to the eye can lead to the development of cataracts
Other eye diseases: such as increased pressure in the eye (glaucoma), abnormal lens position (lens luxation), and inflammation inside the eye (uveitis).
How Does A Veterinarian Diagnose Cataracts?
Your veterinarian will perform a clinical examination of your pet to check for signs of a cataract and a potential underlying cause. This may include:
Applying an orange dye (fluorescein) to check for any damage to the surface of the eye
Checking the pressure inside the eye (intraocular pressure) to ensure it isn’t raised (glaucoma)
Performing a Schirmer Tear Test to evaluate tear production and rule out a dry eye
Using an ophthalmoscope (a handheld instrument) to check the structures inside the eye
Blood and urine tests if necessary to rule out diabetes and other conditions
Blood pressure checks to assess for high blood pressure
In some cases, referral to an ophthalmologist specialist may be needed to identify the cause of a cataract.
How Do You Treat Cataracts?
The only treatment for cataracts that can restore vision is surgery under a general anesthetic. This procedure is called ‘phacoemulsification’ and is generally performed only by a specialist.
Phacoemulsification involves removing the material from the lens and replacing it with an artificial lens. In most cases, this will restore eyesight and prevent any other complications associated with cataracts.
As with any surgery, there are always risks. The risks of cataract surgery include inflammation within the eye, infection, blindness, and ulcers. In rare cases, these complications may result in the loss of the eye. Also, this surgery is very expensive. After surgery, dogs will need to be monitored closely and will need to have eye drops applied. In most cases, oral medications will need to be given and activity restricted.
If you decide that surgery is not appropriate for you and your pet, or if the cataract is only mild, then your veterinarian may recommend applying anti-inflammatory eye drops. Your dog will need to be closely monitored for progression and complications associated with cataracts, such as pain and high pressure (glaucoma).
How Can I Prevent Cataracts?
Unfortunately, there is no way to prevent cataracts. However, certain breeds are at particular risk of eye disease so it is always advisable to do your research before buying a dog. If you are in any doubt about whether a breed you are interested in is at risk of eye disease, then contact your veterinarian who will be able to guide you.
Cataracts can occur at any age, although older dogs and those with diabetes are at a higher risk. Some cataracts are mild and progress very slowly, whereas others progress rapidly and sadly, lead to complete blindness. Although surgery is generally very effective and restores complete vision, it is an expensive procedure and does carry a risk of complications. If you are worried your dog may have cataracts, contact your veterinarian who will be able to diagnose this condition, and arrange a referral to an ophthalmologist for treatment if this is something you wish to pursue.
Frequently Asked Questions
Are cataracts painful?
Although a cataract is not painful, cataracts can lead to complications that are painful such as high pressure inside the eye, or movement of the lens inside the eye to an abnormal position. You may notice squinting, redness, or a watery eye if a cataract is causing pain.
How much does it cost to surgically remove cataracts?
The cost of cataract surgery will depend on several factors. For example, whether both eyes are affected or just one, what other tests or treatments are needed, and if there are any post-operative complications. In general, the surgery averages around $3000-$4000.
Can you treat cataracts without surgery?
If surgery is not an option or is not appropriate for your pet, your veterinarian may recommend eye drops to help manage the condition. However, the only way to restore vision is surgery.