What is the ocular abnormality in this delightful Silkie bantam? What might be causing it and should we be concerned?
Here’s a closer picture – the bluey-greyness is corneal oedema, ocurring bilaterally and I guess the key differential here is to decide whether the diagnosis is glaucoma or uveitis. The intraocular pressure was 8mmHg and so uveitis is the diagnosis – there’s a pretty miotic pupil too though its difficult to see it here. Topical steroid would be of value but of course atropine wouldn’t work as a mydriatic, since birds have a striated muscle iris. The real concern is over a systemic disease. Avian flu, very topical at present, gives oedema in the eyelids and conjunctiva not cornea, and anyway the bird was fine systemically. Newcastle disease can give uveitis(Obaldia and Hanson: Effect of Newcastle disease virus on ocular and paraocular tissues in experimentally inoculated chickens. Avian Disease 1989;33:285-90) as can E coli (Nakamura and Abe: Ocular lesions in chickens inoculated with Escherichia coli. Canadian Journal of Veterinary Research 1987 51:528-30) and even Marek’s disease (Smith et al: Ocular manifestations of Marek’s disease.Investigative Ophthalmology 1974 13:586-92) although this latter agent causes it through iridal lymphoid neoplasia. I must admit to being at a bit of a loss to explain the relatively sudden bilateral uveitis and corneal oedema here – any ideas?!