A Clinical Case from the Archives : 14/07/2005

Posted on July 14, 2005 by davidwilliams

[tab name=”The Case”]This monitor lizard is one of several showing these ocular signs. What is the lesion and what might be causing it?[/tab][tab name=”David’s view”]This animal has a cataract. It lives under a fairly strong UV light sourcae as do many other reptiles, so this could be causing its lens opacities. On the other hand all this group of monitor lizards are pretty inbred, so maybe it has an inherited cataract. Here’s a green tree monitor lizard – a completel;y different species – but with a mature cataract. Perhaps diet could be a factor? It is very difficult to be sure, but important to find out in an endangered species where captive breeding might be a key to survival in the wild – without cataract![/tab][end_tabset] 

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A Clinical Case from the Archives : 14/07/2005

Posted on July 14, 2005 by davidwilliams

[tab name=”The Case”]Sabine Volopich has kindly let me use this great image of a strange corneal lesion in a tortoise. Have you seen anything like this? What could be going on?[/tab][tab name=”David’s view”]White or yellow corneal lesions could be lipid, or cellular infiltrate or scarring but this is a reptile so its going to be a bit different isn’t it?! It seems as though these deposits, seen after hibernation, are proteinaceous in nature. Some slough naturally while others, like this one, require application of a proteolytic ointment like Kymar, which contains alphachymotrypsin. In fact Kymar doesn’t seem to be available these days, so Sabine used alphachymotrypsin from Sigma at about 1mg/ml. Thanks for that Sabine![/tab][end_tabset] 

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A Clinical Case from the Archives : 09/07/2005

Posted on July 9, 2005 by davidwilliams

[tab name=”The Case”]I was asked to examine this horse after a pre-purchase examination. The 10 year old grey horse has a melanoma under its tailbase and these lesions in its conjunctiva. What are they and do they signal something serious?[/tab][tab name=”David’s view”]Here’s the melanoma on the tailbase – sorry if its a bit out of focus but I’m not as good at taking pictures of bums and of eyes! The consensus here is that melanomas are only very rarely distantly metastatic and that these grey lesions are likely to be benign naevi and not metastatic foci. But I’d be glad to know your opinion – the vendor is not keen to investigate further so we may never know![/tab][end_tabset] 

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A Clinical Case from the Archives : 09/07/2005

Posted on July 9, 2005 by davidwilliams

[tab name=”The Case”]This ten year old labrador is presented with a mass protruding from its upper conjunctival sac. When the dog gets excited or the mass is knocked it expands dramatically, as shown here, only to return to normal size after about half an hour. What might this be and how would you manage it?[/tab][tab name=”David’s view”]This is a mast cell tumour, which degranulates liberating histamine when mildly traumatised. I thought we might be able to dbulk it substantially by surgery prior to some chemotherapy, but our oncologists thought that prednisolone and chlorambucil orally would have the same effect. This has just about turned out to be the case as you can see here after two weeks. It hasn’t cured the problem, but then neither would surgery longterm I guess unless we exenterated the orbit which the owners weren’t keen on, given that the other eye is already blind. Control seems the best option rather than cure.[/tab][end_tabset] 

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A Clinical Case from the Archives : 27/06/2005

Posted on June 27, 2005 by davidwilliams

[tab name=”The Case”]Not a difficult question this if you’ve seen one of these before – a corneal sequestrum in a Persian cat. But what would you do with it?[/tab][tab name=”David’s view”]These can be very difficult to deal with – remove them with a superficial keratectomy and they may extend throughout the cornea. Leave them be and they may eventually erode through the cornea and perforate the globe. A conjunctival flap after a keratectomy might work but the best treatment is a corneoconjunctival transposition graft as described by Stacey Andrew in her excellent 2001 paper ‘Corneoconjunctival transposition for the treatment of feline corneal sequestra’ in Veterinary Ophthalmology 4:107-11. The only trouble with this particular case was that the black deposit was actually in the epithelium of a graft I had placed after removing a deep sequestrum in this little cat, under a year old. Thankfully the new sequestrum lifted off with just topical anaesthetic leaving this cornea underneath. I just have to cross my fingers that the same thing doesn’t happen again! Is that all I can do?[/tab][end_tabset] 

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A Clinical Case from the Archives : 21/06/2005

Posted on June 21, 2005 by davidwilliams

[tab name=”The Case”]I found this dog happily sitting in the waiting room of a practice I see referral ophthalmology for, ready to have its yearly boosters. Curious, I asked its history. The dog had a cat claw injury followed by uveitis then glaucoma. Now it has settled down looking like this. What are we seeing here and are there any problems associated with this condition?[/tab][tab name=”David’s view”]This dog has phthysis bulbi, where uncontrolled intraocular pathology has resulted in ciliary body degeneration and a reduction in aqueous production. Intraocular pressure was 5mmHg. The globe shrinks but without the pain and exposure associated with chronic glaucoma. The eye is blind, which I guess is quite a problem (!) but other than that the globe is quiet with the only possible problem being chronic infection in the ventral conjunctival sac which is bigger, the eye having shrunk in size. This picture shows a cat eye in the process of phthysis – once the process has started, I’m not aware of any way of halting it, apart possibly from trying to stop in inciting pathology in the first place.[/tab][end_tabset] 

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A Clinical Case from the Archives : 19/06/2005

Posted on June 19, 2005 by davidwilliams

[tab name=”The Case”]This twelve year old poodle has had a cataract in this eye for some time. Recently there has been a change and the owner wants to know what is happening. Can you enlighten her?[/tab][tab name=”David’s view”]There is resorption of the cataract at its equator (a technical way of saying round the edge!)and some associated lens-induced uveitis. Note the sparkling elements in the eye in this picture – these are probably cholesterol deposits which are characteristic of a resorbing cataract. With any luck both of these will resorb further to allow some return of vision – the only treatment necessary may be topical steroid to control the mild intraocular inflammation associated with resorption.[/tab][end_tabset] 

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A Clinical Case from the Archives : 18/06/2005

Posted on June 18, 2005 by davidwilliams

[tab name=”The Case”]This 6 year old Jack Russell terrier is presented for a non-ocular complain but, being a budding ophthalmologist you are drawn more to the blueish tinge in its cornea than its anal gland that need squeeezing (not an unreasonable diversion from such a task in my view at least!) Why is the cornea thus coloured, what is the diagnosis here and what would you do?[/tab][tab name=”David’s view”]The diagnosis is lens luxation, inherited and relatively common in this breed. The edge of the lens can be seen, showing it to be in the anterior chamber, although there is no aphakic crescent as seen in this cat. The cat had an intraocular pressure of 38mmHg while the dog has a pressure of 18mmHg when you measured it at least. The corneal oedema (for that is what the blue tinge is) is most likely caused by the lens abutting on the corneal endothelium and probably not from glaucoma while the cat certainly has glaucoma. While lens removal is the standard treatment for lens luxation, both thee animal present somewhat of a problem. Is the cat’s lens luxation the cause of the glaucoma or the other way round? As we don’t see primary glaucoma in cats, that probebly is the case and lendectomy is called for. The dog presents rather a difficult problem. Although lens removal is what the books recommend, the owner says the eye has been like that for the last year, the dog’s vision is normal and she asks what is to be gained by operating. While one can say that future glaucoma will be avoided, I think the best thing is to refer the dog on to a specialist to discuss the condition and its treatment with the owner![/tab][end_tabset] 

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A Clinical Case from the Archives : 14/06/2005

Posted on June 14, 2005 by davidwilliams

[tab name=”The Case”]This six year old labrador bitch has developed a darkened area on her lateral iris. Should we be concerned – is this likely to be neoplastic? What should be done?[/tab][tab name=”David’s view”]Here is a closer view of the lesion. To tell you the truth I’m not sure about this one. If it were a cat I’d be worried it was difuse iris melanoma with profound systemic consequences for the animal. But as its a dog I’m not at all sure whether it is a melanoma or merely benign iris hyperpigmentation. We are watching and waiting at present – please e-mail me if you think we should be doing something different![/tab][end_tabset] 

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A Clinical Case from the Archives : 11/06/2005

Posted on June 11, 2005 by davidwilliams

[tab name=”The Case”]This young human has developed a strange ocular luminescence concurrent with his tenth birthday. What other animal uses bioluminescence to see?[/tab][tab name=”David’s view”]The dragonfish, living at a depth of 1000m, uses red bioluminescence to detect its prey. At that depth, the only natural light is at the far blue end of the spectrum, so by using red bioluminescence and having a retina, unlike those of its prey, which is sensitive to light at that wavelength, the dragonfish can detect its prey while they can’t see it coming![/tab][end_tabset] 

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