Cloudy eyes can be normal for senior dogs.
If your old dog’s eyes look kind of cloudy, chances are he needs glasses, not cataract surgery.
Although humans have quite different eyes than dogs, the lenses that allow us to focus are affected by similar diseases. As my ophthalmologist explained several years ago, I now need reading glasses because I have presbyopia which he took far too much pleasure in translating as “old person’s eyes”.
As our eyes age, the lenses become stiff and can no longer focus well on objects close-up. This starts to happen in most dogs at the age of 6, but we rarely notice any changes in our canine friends except for increasing cloudiness, a kind of bluish haze inside the eye. Vets call this “lenticular or nuclear sclerosis”.
Observant dog owners might see some hesitancy on stairs or less accuracy with Frisbee-catching as the sclerosis progresses. However, since dogs are born with pretty poor vision for objects closer than 30 to 50 cm, the condition generally has little impact even in very senior pets.
Cataracts, on the other hand, can cause significant blindness in dogs as they do in people because they may completely block the transmission of light through the lens. The majority of cataracts in dogs are hereditary and the list of susceptible breeds is long. They can develop at any age in life.
Compared to lenses with sclerosis, those with mature cataracts look very dense and white. They might start as just a few white dots and the speed with which they progress is variable. A sweet chihuahua we saw last week developed a blinding cataract in one month. The other eye is only mildly affected so far.
Dogs with diabetes can go to bed with normal eyes, yet wake up blind the next day. About 70 per cent of diabetic dogs get cataracts because the amount of sugar in their blood damages the lenses. Cataracts can also be caused by a blow, penetrating injury, electric shock or inflammation from disease. If you notice a haze in your dogs’ eyes, have him examined by a vet to see if further testing is required.
The good news is that surgical removal of cataracts has a 90 per cent success rate in healthy dogs, particularly if done early. Veterinary ophthalmologists use a technique called phacoemulsification to remove the cataract and replace the lens with an artificial one. The surgery is very similar to the procedure most of us are heading for ourselves as we get older.
Unfortunately, OHIP doesn’t cover dogs and canine cataract surgery costs are generally from $4000 to $5000, putting it out of reach for many pet owners. That’s still a lot less than some people are paying to have their own lens replacement surgery done early just because they hate their reading glasses.
Thanks to keen ears and noses, dogs blinded by cataracts often do well with careful management of their environment. Regular exams are advised to monitor for secondary inflammation or glaucoma.
More information is available online at Veterinary Partner.
Dr. Fiona Gilchrist
Hillcrest Animal Hospital
November 2013
