thanks Anne and Masons_mum for your replies...
i wish i could just get them flushed to clear, but the opthamologist ruled that out and said surgery was only way to go, as problem is caused by the deformed/flattened nature of his face (and he may not even have complete tear ducts, but don't care to think about that!). He does get lots of eye boogers, but has never had an infection in the eye - just the skin below his eyes.
The eye clinic has assured me as far as "eye surgery" goes it is a fairly routine procedure, but it is still surgery...