This middle aged diabetic Golden Retriever was presented with this somewhat alarming ocular appearance. What might your differentials be, how could you test to confirm the diagnosis and is there a link with the diabetes?
The third eyelid protrusion signals an enophthalmos and the pupils were constricted this some anisocoria (though not easily visible here). The upper eyelids were somewhat lowered. This triad of miosis, ptosis and enophthalmos is classic for Horner’s syndrome. Topical 0.5% phenylephrine resolved the signs in less than 10 minutes, suggesting a third order lesion. While common in Golden Retrievers as an idiopathic problem, most of those are second order lesions. It is highly likely that this is a result of a diabetic neuropathy, as previously reported by Holland in 2007 (Bilateral Horner’s syndrome in a dog with diabetes mellitus. Veterinary Record 160:662-4). The owner was given a supply of phenylephrine to use before taking the dog for a walk, to improve vision which was otherwise compromised by the protruding third eyelids.