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?
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!