A friend was constantly getting pink-eye. Meds would take care of it for about a week, then it would return. This went on for a couple of months.
It turns out that the cat was cuddling up to her while she slept. And by cuddling up, I mean rubbing it's arse up against her face at night.
The cat is now locked out of the room at night ... and the pink eye has gone away for over 6 months)
I wouldn't be surprised by something similar being the case here. My cats are sleep thieves and constantly pester me when sleeping. They don't cope well with being locked out though. Make a huge racket!!