We recently saw a 10-year-old, West Highland white that had developed a middle ear infection and facial paralysis.
Following treatment and further investigation, it turned out the poor little chap had concurrent hypothyroidism. Several weeks later, I noticed the eye the same side as the ear infection had developed a mucopurulent discharge and mild keratitis.
On checking its Schirmer tear tests, this was markedly reduced for that eye, and borderline for the other. A bit of research indicated facial paralysis can affect both tear and saliva production.
The good news is the little chap is doing well with false tear preparations.