does solution in a lap band evaporate?

I have had my lap and for 6 years and just the past few months it feels like I can eat everything.  I have not seen my DR in 1.5 years.  I am going in today but I wonder if it does/could evaporate and I just need it filled up again?

 Did your doctor answer this for you? How'd your appointment go? 

Actually, the last fill I had was in August of 2013.... longer than I thought and my band had all the fluid in it!  I was excited.  She did give me a slight feel and I can already feel the restriction!

That's good news. I'm glad things went well.