Question from Anne Wood
I have a border collie 5 years old. Hes a very frightened dog but he is completly blind in 1 eye and partly blind in the other the vet told me it was progressive retinal atrophy and now he has a cateract on top of his blind eye, is there anything that can be done for him please and thank you for taking the time to read this.
Answer from Shanika Online Vet
Hi Anne, thank you for your question regarding your dog’s eyes and behaviour.
So what is progressive retinal atrophy (PRA)?As the name suggests it is a condition where there is gradual degeneration of the retina (layer lining the back of the eye). PRA is usually an inherited condition and sadly there is no cure for it, however on the positive side it rarely causes pain. There is no treatment for PRA at present, there have been some trials of using antioxidants to slow down the degenerative process but the results of this are as of yet inconclusive.
Cataracts are a common finding along with PRA; a cataract is cloudiness in the lens of the eye. The loss of vision caused by the PRA itself means that cataract surgery is rarely advised as there will not be much improvement to vision as a result of the surgery.
How would I know that my dog has PRA and how is it diagnosed?Owners usually notice a loss of vision in the pet, most noticeable in low light conditions, their pets pupils may appear more dilated with an increased glow/shine (tapetal reflex) from the back of the eye.
A diagnosis is usually made when your vet or ophthalmologist examines your dog’s eyes and notices the damage to the retina.
What can I do for my dog with PRA?
Sadly there is no treatment for PRA itself but as it is a painless condition then it is more a case of trying to help your dog to adjust to his gradual loss of vision. Generally the other senses smell, hearing, touch and taste increase to try and compensate for the one that is deteriorating.
You can take steps to make your home environment easier for your dog with poor or no vision to get around. Keep large pieces of furniture in the same place, use stair gates to block off dangerous areas, when out and about use lots of vocal and physical clues to let your dog know where you are and to provide reassurance.
Dogs are incredibly resilient animals and adjust very well to changes especially when they are gradual. I hope that this answer has helped you to understand a little bit about PRA and how both you and your dog can still lead a happy life together.
Shanika Winters MRCVS
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[caption id="attachment_565" align="alignleft" width="300" caption="Blind cat showing dilated pupils"][/caption]
One of the most common causes of sudden blindness in an elderly cat is due to high blood pressure (hypertension). The increased pressure pushes the light sensitive layer (retina) away from the back of the eye and this can happen literally overnight.
The affected cat will have very widely dilated pupils even in bright sunlight and there might be some blood visible when looking into the eyes. They will appear to be disorientated, bump into things and might vocalise excessively.
[caption id="attachment_569" align="alignright" width="320" caption="Monitoring a cat's blood pressure"][/caption]
The usual cause of raised blood pressure in cats is an excess of thyroid hormone (hyperthyroid) but it can also be due to kidney disease or diabetes. This is why it’s important for the vet to take blood tests to decide which condition to treat.
We monitor cats’ blood pressure in a similar way to human doctors by inflating a cuff just above the paw on a front leg but we listen for blood flow with an ultrasonic probe rather than a stethoscope. Some cats are calmer if the cuff is placed around the tail base. A few readings are usually taken to make sure that the blood pressure has not been raised through stress.
[caption id="attachment_573" align="alignleft" width="192" caption="Blood Pressure Monitor"][/caption]
Drugs are very successful in bringing a cat's blood pressure down to normal but the blindness is usually permanent. Cats are extremely adaptable when it comes to finding their way around the house and finding their food but they are not safe to allow outside due to all the dangers out there.
There are a number of other causes of blindness but these generally come on more slowly:
Glaucoma is the same condition as people get where there is an increased pressure within the cat's eye. This is usually seen as a very angry painful eye and the white of the eye appears red due to the many new blood vessels. Drops can control the condition if caught early enough but if it reaches the stage where the eye is visibly swollen or ulcerated, then removal of the eye (enucleation) will usually be suggested. Glaucoma can be found in just one eye or both.
Cataracts are much less common in cats than dogs and would be seen as a misty or pearly lens. Tests would be required to rule out diabetes which can be a cause.
Tumours within the cat’s eye are occasionally discovered when the eyes are examined with an ophthalmoscope. Loss of vision would be slow to develop in these cases and often in only one eye initially.
If you have a pedigree cat (particularly an Abyssinian) who starts to slowly lose vision early in life, there is a possibility of Progressive Retinal Atrophy (PRA) which is a genetic disease, very similar to the condition in some pedigree dogs. There is no treatment but the cat usually has time to adapt to the slow loss of vision.
Something we hardly ever see these days is Taurine (an amino acid) Deficiency. Modern complete diets have all the taurine a cat needs but it is just possible that a cat fed exclusively on tinned tuna could develop slow onset blindness due to this deficiency. If caught early enough, the loss of vision can be stopped or even reversed.
Most cats adapt very well to blindness and go on to enjoy a good quality of life. Some adapt so well that it would be hard for a casual observer to know they were blind.
If you are worried about any problems with your cat's eyes, please contact your vet or use our interactive Cat Symptom Guide to help you decide what to do next.
[caption id="attachment_465" align="alignleft" width="310" caption="Skitzo under anaesthetic, showing the tumor on the edge of his bottom eyelid"][/caption]
Vets are very used to dogs, cats and small furries developing growths on various parts of their anatomy. We very often take a small sample of the growth by means of a needle (known as a fine needle aspirate or FNA) before deciding what action to take. In most cases the growth is removed surgically.
Skitzo was a 9 year old cat with something of an attitude to being handled by vets (and sometimes his owner). A fast growing lump had come up beneath his right eye and was very close to the edge of the eyelid. A fine needle aspirate was impossible in this case without him being anaesthetised so we decided to remove the lump and send it off to the lab for the pathologists to tell us what tissue type we were dealing with.
The most important thing they can tell us is whether the tumour is benign or malignant. Sometimes growths can seem to be benign but still cause problems by recurring in the same place they were removed. The worst type of tumour is one which is malignant and which has the potential to spread (metastasise) to the lungs or other organs via the blood stream.
Skitzo’s tumour was a surgical challenge because it was so near to the margin of the eyelid. If too much tissue is removed, the lower lid will turn outwards (called ectropian) leaving a gaping pocket and encouraging infection, inflammation and an overspilling of tears. On the other hand, cutting too close to the growth risks tumour cells being left behind and the growth returning very quickly.
[caption id="attachment_478" align="alignright" width="300" caption="Skitzo after the operation, still under anaesthetic"][/caption]
Dissolving stitches were used because Skitzo was never going to let us take them out when he was awake. We fitted him up with an Elizabethan collar so that he could not scratch or rub the stitches out. The plastic collars look unwieldy and owners are often tempted to take them off as soon as they get home but most animals adapt to them very well and it’s only a relatively short time before the stitches are removed and life returns to normal. Nylon stitches are usually removed in 8 to 10 days after the operation but this can be extended if the skin is especially thick, under tension or if the animal is receiving steroid treatment.
Skitzo’s tissue sample came back as a benign growth and there is every prospect that the surgery has been a complete success. Fortunately Skitzo’s pet insurance company paid the bill for the surgery and the laboratory tests which were needed.
If you are concerned about lumps or any other problems with your cat, please contact your vet or use our interactive Cat Symptom Guide to help you decide what to do next.
Joe Inglis BVSc MRCVS is the vet for the One Show, This Morning and BBC Breakfast. He runs his own line of natural pet food called Pet's Kitchen
I often find myself sympathising with my patients, and feeling for their distress and pain when they are suffering from illnesses or injuries – and never more so than when their problem involves their eyes. There’s something about injuries and diseases of eyes that really affects me more than almost any other type of problem and I can really empathise with how my patient must be feeling. Having an ulcer or other injury to an eye must be horribly painful, not to mention the psychological impact of dealing with the loss of some or all of your sense of sight.
When Sylvester the cat came into the consulting room last week and clambered miserably out of his wicker basket, my heart sank and I felt an immediate sense of shock and distress when I saw his problem. His left eye was barely recognisable, with a large grey ulcer dominating the cornea and angry red blood vessels invading the usually clear surface of the eye from the sides. This was not Sylvester’s first visit to the surgery for this problem, but it was the first time that I’d seen him, and I immediately knew that we needed to do something drastic if we were going to save his eye – and bring his obvious suffering to an end. Looking at his records it was clear that this ulcer had been grumbling on for a couple of weeks by this stage, and despite ongoing treatment with medicated drops it was getting worse rather than better.
At this stage we had a couple of options to consider. One was to refer Sylvester to an eye specialist, but this was quickly ruled out by his owner on the ground of cost and lack of pet insurance cover. The second option would be to continue with medical therapy, taking a swab to find out exactly which bacteria were causing the ongoing damage and preventing the ulcer from healing and potentially changing the eye drops once these results were known. The downside of this course of action was that it would do little to alleviate Sylvester’s discomfort in the short term, but after talking to his owner and explaining that the only other option would be surgery to remove the eye, we agreed that we would try this first.
So I took a swab from Sylvester’s eye and sent it away to the laboratory to see what they could tell us about the infection. While we waited for the results we did what we could to manage Sylvester’s discomfort with painkillers and anti-inflammatories, and then as soon as the results were in we started him on an aggressive course of antibiotics that were targeted specifically at the bacteria the swab had isolated. At this stage I was still optimistic that we could save Sylvester’s eye, but unfortunately things didn’t work out as planned and despite our new treatment regime, the ulcer stubbornly refused to respond and after a week of treatment it became clear to me that we were left with only one option – to remove Sylvester’s eye.
Breaking this news to his owner was not easy, but she did appreciate that it wasn’t fair to let him continue to suffer as he was doing given the now very slim chance that we would be able to save his eye. After a couple of long – and emotional – consultations, we agreed to go ahead and last Friday Sylvester came into the surgery for his operation.
[caption id="attachment_267" align="aligncenter" width="576" caption="Sylvester the cat under anaesthetic after the operation to remove his eye"][/caption]
Removing an eye is an operation I really don’t enjoy, as I can’t help but really feel for the poor animal that is losing such a crucial part of their anatomy, and the operation itself is also technically tricky and pretty gruesome. Sylvester’s operation went as well as I could expect, but it was not one that I finished with a sense of satisfaction – I felt good that we had brought Sylvester’s suffering to an end, but I also felt as though we’d failed him by having to resort to such a procedure.
If you have any concerns about your cat's eye please contact your vet or use the interactive cat symptom guide to help you decide what to do next.