Updated November 29, 2020
‘At A Glance (Details Below)’ Essential Facts
If A Dog Has A Cataract
- Don’t panic: most of what are called ‘cataracts’ are part of normal ageing
- To check for true cataracts you need to see either a vet or an eye specialist
- Senile lenticular sclerosis does not cause blindness and needs no treatment, whereas cataracts require removal to restore vision
Now dive deeper.
Is It A Cataract?
Many owners of older dogs with hazy eyes get told that their dog has cataracts, and then live in fear of their dogs going blind. The truth is most of these dogs have nothing of the sort. After reading this, you can be the one to correct the next giver of bad advice.
Cataracts do happen in dogs and are probably at least as common as in people. When they occur they are very important, both as common causes of bindness and signs of other important diseases such as diabetes and progressive retinal atrophy (PRA).
However, the vast majority of dogs said to have a cataract instead have ‘senile nuclear sclerosis’ (or lenticular sclerosis). This is the condition which proves to me more than any other that we are not supposed to live forever.
What Is Senile or Lenticular Sclerosis?
As we age, our lenses continue to create new layers from the inside of their capsule. This creates an onion-like effect, with older layers moving towards the centre. The problem is that despite the new lens material being produced on the edge, the lens cannot get any bigger. Therefore, the lens becomes more and more dense in its centre, or nucleus.
By about 8 years of age, this dense nucleus starts getting visible, and as the dog ages it reflects more light, giving the dog’s eyes a bluish-grey look as in the picture above. The trick is that most light still goes straight through as normal and the dog’s sight is hardly affected if at all.
What Does A Cataract look Like?
It only takes a quick visit for a vet to tell the difference by seeing if the retina is visible (as in nuclear sclerosis) or not (as in the cataracts seen here). You can also see in this picture of mature cataracts how the lens has irregularities and it much whiter than the earlier picture.
If you are concerned by advice from others about your dog’s eyes having cataracts, please don’t lose sleep as it is much more likely that they are wrong. However, do make an appointment with your vet just to be sure. Cataracts eventually cause blindness but can be removed by a vet eye specialist to restore vision. That’s what the pictured dog had after this photo.
Importantly, cataracts caused by diabetes need to be treated very early before they swell up and rupture their capsules. This can lead to severe uveitis and an inability to implant the new lens.
What Happens When Dogs Go Blind?
Another myth worth tackling is that a dog going blind is a big problem. Most owners don’t notice their dog’s blindness, and the dogs don’t seem to mind as long as they can sniff their way through the day.
If all this sounds a bit blasé, try to see the world from a dog’s point of view. Unlike humans, vision is probably their third most important sense. If you really feel like messing with your mind, read more here on this concept of ‘umwelt’. It might just change how you see animals!
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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. These help topics are from a series regularly posted on email and Twitter. Subscribe via email here to never miss a story! The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.