A Clinical Case from the Archives : 30/10/2005

Posted on October 30, 2005 by davidwilliams

[tab name=”The Case”]This three year old Labrador is presented to you as the owner is concerned about its eyes, although vision seems to be normal. What is wrong and what tests would you do to determine what is wrong?[/tab][tab name=”David’s view”]There is mild inward strabismus (esotropia) bilaterally, only seen well with distant direct ophthalmoscopy as here. Direct fundoscopy also shows some fine nystagmus with the fast phase outwards. Assessing eye movements on moving the head (passive duction test) followed by grasping the globe conjunctiva after local anaesthetic and moving the eye laterally (forced duction test) shows no abnormality. In the labrador the strabismus is probably neurological as it is in Siamese cats, while in this Cavalier King Charles spaniel it was impossible to move the globe medially and there was a lateral post-traumatic restritive strabismus which the owners chose not to treat as the dog was not impaired by the problem.[/tab][end_tabset] 

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A Clinical Case from the Archives : 29/10/2005

Posted on October 29, 2005 by davidwilliams

[tab name=”The Case”]This five month old Neopolitan Mastiff presents with this appearance of the nicitating membrane in both eyes. What is happening and what should be done to correct it?[/tab][tab name=”David’s view”]The T-shaped cartilage of the nictitating membrane is scrolled, as can be seen a bit more clearly in this view immediately before surgery. The kinked or scrolled portion needs to be excised through an incision through the conunctiva of the inside face of the nictitating membrane. Here the conjunctiva is less tightly adhered to the cartilage making the first separation easier. The only side effect that warn owners about is that this destablisation of the nictitating membrane may lead to a prolapse of the nictitans gland. In some Mastiffs the third eyelid is just too long and needs to be shortened but not in this case.[/tab][end_tabset] 

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A Clinical Case from the Archives : 29/10/2005

Posted on October 29, 2005 by davidwilliams

[tab name=”The Case”]This thirteen year old cat with renal failure from a rescue centre has a painful eye – what is the problem and what, given that surgery is out of the question, might you do?[/tab][tab name=”David’s view”]This is a really nasty deep ulcer which could do with a conjunctival pedicle flap or corneoconjunctival transposition graft. In this sort of a medical and financial no-surgery nightmare we used autologous serum twice daily and either prayed or crossed our fingers (or both!) depending on our belief in someone ‘up there’ in control (or otherwise!). Clearly the cat had a direct line to the Almighty (or maybe it was the serum that worked a miracle!) as here is the result ten days down the line with the corneal deficit filled with a fibrous tissue reaction. Notice how much wider the palpebral aperture is now the ocular surface pain has gone. I’m sure we don’t realise enough just how painful these conditions are in many cases and how topical NSAIDs (I prefer ketorolac in Acular) and a systemic analgesic too can be really valuable.[/tab][end_tabset] 

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A Clinical Case from the Archives : 29/10/2005

Posted on October 29, 2005 by davidwilliams

[tab name=”The Case”]How annoying! You’ve forgotten your ophthalmoscope on a visit to a friend’s house and he shows you his 4 year old labrador. His own vet has used one antibiotic after another in the eyes with no effect. From this distance can you see its problem – what test would you do with what potential diagnosis in mind?[/tab][tab name=”David’s view”]Did you see the mucopurulent discharge in both eyes? That’s presumably what has led his vet to think of an infectious conjunctivitis though after being blasted with fusidic acid, chloramphenicol, gentamicin and chlortetracycline they must be as sterile as the inside of an autoclave! You may have forgotten your ophthalmoscope but you have a Schirmer tear test in your pocket and the result is 3mm in each eye. But why does dry eye produce this discharge? Ironically histology shows a reduction rather than an increase in mucus-producing goblet cells in such cases as Cecil Moore has shown(Density and distribution of canine conjunctival goblet cells.
Invest Ophthalmol Vis Sci. 1987 28:1925-32) with topical cyclosporine improving this (Effect of cyclosporine on conjunctival mucin in a canine keratoconjunctivitis sicca model. Invest Ophthalmol Vis Sci. 2001 42:653-9). Note also the periorbital and nasal alopecia – while the hair loss around the eyes might be caused by rubbing, I’m not at all sure about the rest of the skin problem – we’ll refer him on to the dermatologist![/tab][end_tabset] 

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A Clinical Case from the Archives : 21/10/2005

Posted on October 21, 2005 by davidwilliams

[tab name=”The Case”]Being a keen proto-ophthalmologist you tend to look closely at the eyes of normal dogs coming for routine vaccination. In this Collie-cross dog you see this retinal abnormality. What is it and what does it mean?[/tab][tab name=”David’s view”]The image shows an abnormaly large solitary choroidal vessel characteristic of choroidal hypoplasia in collie eye anomaly. While the condition can occur in dogs other than collies (Rampazzo et al Collie eye anomaly in a mixed-breed dog. Veterinary Ophthalmology 2005 8:357-60, Bedford Collie eye anomaly in the Lancashire heeler.
Vet Rec. 1998 143:354-6) it still remains pretty anomalous, even given teh linkage analysis by Gus Aguirre and Greg Acland’s group (Lowe et al Linkage mapping of the primary disease locus for collie eye anomaly. Genomics. 2003 8:86-95) which showed the gene for choroidal hypoplasia (but not optic nerve coloboma shown here) to be located on chromosome 37, homologous with human 2q35. This is an interesting location as it may be associated with the PAX 3 gene, key in development and mutated in human Waardenburg type 1 syndrome. Does that make it sound less anomalous? Probably not![/tab][end_tabset] 

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A Clinical Case from the Archives : 18/10/2005

Posted on October 18, 2005 by davidwilliams

[tab name=”The Case”]This horse had painful blind eye a week ago associated with nasal discharge. It seems to be recovering vision somewhat and now has developed these lesions around its optic disc. What is the condition and what is the prognosis?[/tab][tab name=”David’s view”]This is probably an equine herpesviral retinitis with the development of what have been known as peripapillary ‘butterfly’ lesions. The signs are less severe in the other eye with only some of these small hyper-reflective ‘doughnuts’ in the retina. The prognosis for return of vision is reasonable especially as the inflammatory aspects of the lesion seems have regressed by now. Quite a few horses are seen with these changes as chronic post-inflammatory lesions and with no discernable visual defects.[/tab][end_tabset] 

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A Clinical Case from the Archives : 18/10/2005

Posted on October 18, 2005 by davidwilliams

[tab name=”The Case”]We are just about to operate on this Jack Russell’s eye – but what is the problem and what are we going to do?[/tab][tab name=”David’s view”]This is a lens luxation – some would phacoemulsify the lens but another rather older option is to perform an intracapsular lendectomy, as you can see here with the operating microscope light rather beautifully highlighting the lens as it is eased out using a vectis.[/tab][end_tabset] 

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A Clinical Case from the Archives : 14/10/2005

Posted on October 14, 2005 by davidwilliams

[tab name=”The Case”]Here’s a bit of a teaser for you! What’s wrong with this cat’s liver?[/tab][tab name=”David’s view”]Notice the amber colour of the cat’s iris. Its a pathognomonic sign of a portosystemic shunt. But what causes the amber colouration? Answers on an e-mail postcard please – I haven’t a clue![/tab][end_tabset] 

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A Clinical Case from the Archives : 14/10/2005

Posted on October 14, 2005 by davidwilliams

[tab name=”The Case”]I chose one of the blood donor greyhounds from the vet school today to show a group of students what a normal canine retina looked like. But what did I find?[/tab][tab name=”David’s view”]There’s a well demarcated area of tapetal hyper-reflectivity just by the optic nerve head (shown very dark as I had to reduce the exposure so the hyper-reflective area didn’t flood the camera with light) and also an apparently darkly pigmented area dorsolateral to the disc. Actually taking another photo from a slightly different angle (easy with my new digital fundus camera!) shows that area reflective and the other one near the disc dark. These are areas of post-inflammatory degenerate retinopathy which have probably been caused by Toxocara canis visceral larva migrans in this dog which was never wormed as a puppy. Although its very common in unwormed working dogs very little work has been published on this – the best paper is Hughes and coworkers on sheepdogs in New Zealand from way back in 1987 (Multifocal retinitis in New Zealand sheep dogs.
Veterinary Pathology 24:22-7. They found over a third of dogs with lesions.[/tab][end_tabset] 

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A Clinical Case from the Archives : 10/10/2005

Posted on October 10, 2005 by davidwilliams

[tab name=”The Case”]This cat came to the vet for a routine appointment but had an intraocular haemorrhage while sitting in a dog-filled waiting room. What do you see in the retina and how might explain the haemorrhage? What diagnostic and therapeutic steps might you take?[/tab][tab name=”David’s view”]Stress had raised the poor cat’s already supranormal blood pressure through the roof resulting in the bleed. By the time I got to see the cat (a 15 year old polydypsic individual)the iris haemorrhage had all but resolved, but given time the numerous bullous retinal detachments (for that’s what the small circles in the retina are) would develop to complete detachment with blindness. Amlodipine treatment will lower the blood pressure and prevent this, so we can prevent loss of vision. Interestingly while chronic renal failure is almost certainly the root cause of the problem, the blood urea and creatinine were not markely raised in this animal, probably because the cat was drinking so much it was excreting those waste products quite satisfactorily.[/tab][end_tabset] 

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