Trying to figure out what dry eye really is.

[Ariel]

I have recently been diagnosed with blepharitis which has caused me to suffer from dry eye. I'd like to know more about this condition.

Is it normal for the itching to totally go away for days a at time only to reappear later? When it is caused by the meibomian gland oil passages being clogged, which changes tear's chemistry, shouldn't the itching go away as soon and the passages are expressed and the oil flow is restored?