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Friday, 7 October 2011

Cataracts: what are the facts?

My seven-year-old Staffie has just been diagnosed with very early stages of cataracts in both eyes and it’s a minefield of info out there!

I’ll be getting more info on it next week when I go back to the vet but it’s made me realise how common it is in our pooches and there are lots of reasons for it, not all dogs will be blind, some should be treated – others not… brain hurts!! Googling sometimes isn’t a girls best friend!

Would be great to have the real facts down and any help around what a person can do to prolong the sight when diagnosed before things get bad.

Kind regards

Donna, by email

Alison Logan, vet, advises...

Googling will often cause more problems than it solves and especially when it comes to canine health matters. Far easier to tap a vet’s knowledge, so I am glad you are going back to see your vet. I will therefore try to keep it simple.

In order to see, light rays from the outside world in front of the eyes are focussed on the retinas at the back of the eyes, generating nerve impulses which are transmitted to the brain for higher processing and vision. Anything interfering with the light rays as they pass through the eye will therefore affect the information generated.

The lens lies within the eyeball, between front and back chambers. All light rays have to pass through it in order to reach the retina. It is a collection of fibres contained within an elastic capsule. It is transparent and does not have a blood supply because blood vessels running within it would interfere with the passage of light through it. Instead, it is nourished by the fluids within the eyeball.

New fibres are being formed throughout life. In order for the lens not to grow inordinately and outgrow the eyeball, the old fibres move towards the centre of the lens and are compressed, resulting in an inner dense nucleus. This is called sclerosis and is a natural ageing process - there have as yet been no ways identified, of which I am aware, for preventing or slowing it down.

This feature of lens growth underlies the different approaches to cataracts. In the young dog, the lens can be needled and any lens debris left in the eyeball will be naturally absorbed. The nucleus in an older dog’s lens, however, must be totally removed as it would not be absorbed.

Sometimes, it may be said that sutures can be seen. They are to do with the material holding the lens fibres together and are characteristically seen as an upright ‘Y’ on one side of the lens and an upside-down ‘Y’ on the other side.

If an area of the lens or capsule loses its ability to transmit light and becomes opaque, it is said to be an opacity or cataract. There are essentially two main types of cataract:

1. Developmental – e.g. congenital (born with opacity), juvenile

2. Degenerative, e.g. diabetic, traumatic, secondary to a condition such as progressive retinal atrophy

The Staffie is prone to progressive, early onset juvenile cataract formation, said to start at five to eight months of age but often detected as early as three to four weeks of age. An affected dog will be blind by one to three years old. Hereditary Cataract (HC) is inherited as an autosomal recessive and can be identified with a DNA test.

Your Staffie, however, has been found to have cataracts forming at a much older age, suggesting degenerative cataracts. There may be an underlying problem such as diabetes, or it may simply be the start of old age sclerosis. Your vet will be in a better position to advise you since he can do a full health check, perhaps including blood tests.

I do hope this has helped.


  1. Traditional Oriental Medicine views the individual as a whole in which everything affects everything else - body and mind. Within that there are thought to be much more specific links and one of these is that the eyes are linked to the liver. We all know that cataract is linked to diabetes and this may be explained by the fact that fatty liver is common in diabetes.
    On that basis it must be worth trying to minimise the stress and workload on the liver. This can be done by:
    (i) reduce food intake to as little as possible.
    (ii)the diet should be low fat and low protein and consist mainly of complex carbohydrates as are found in whole grains.
    Burns Pet Nutrition adult foods based on brown rice or maize and can meet these criteria. We have a nutrition team who can offer advice on feeding.
    None of this comes with a guarantee that it will stop the progression of the cataracts but there is nothing to lose.
    Best wishes
    John Burns BVMS MRCVS
    Burns Pet Nutrition

  2. The lens is situated within the eye itself, between top and back spaces. All light radiation have to cross through it in order to achieve the retina.

    what is cataract