It is dry eye - keratoconjunctivitis sicca. Optimmune may help - it didn't for Charley.
If you visit France or Germany you can purchase Fradexam, which has worked miracles for Charley. Unfortunately, it's not available here.
I have been treating Charley for over nine years now. It's tedious, but you must persevere for your dog's sake. Viscotears is far better than hypromellose as it is a gel and is longer lasting. You can also purchase Infected Eyes from the chemist for a shade under £5.00. This is chloramphenicol - an antibiotic - and is much cheaper than getting it under another name from your vet.