This 7 year old German Shepherd dog was referred for the unusual appearance of the right eye. This occured rapidly, over the course of a few days and worried the owner (and the referring vet!)but apparantly not the dog. What might be happening here and what might your diagnostic plan include?
Here is a closer look at the affected eye with the depigmentation very obvious but no iris swelling, pathological vascularisation or flare. I must admit that I haven’t an immediate diagnosis here but intraocular inflammation sprang to mind. Vogt-Koyanagi-Harada-like syndrome (isn’t that just a great name!!) is manifest with periocular depigmentation – vitiligo and poliosis – and then posterior segment inflammation often with retinal detachment and blindness. But here the depigmentation is iridal and there is a mild iridocyclitis (anterior segment uveitis) not choroiditis in the posterior segment. I know that because the intraocular pressure was 11mmHg compared with 17mmHg in the normal left eye and the posterior segment is unremarkable. There were some tiny foci of cataract in the lens of this eye and not the left eye. A full work-up would include a blood screen including a serum electrophoresis, titres for all sorts of unusual infectious agents (except that the dog had not been out of the country) and maybe even an aspirate of aqueous and cells from the iris surface. Given that the dog is not in any discomfort of visual impairment however, we decided against such a drastic diagnostic plan and merely tried topical steroid….and phototherapy of course, the results of which you can see displayed here!