Noises and sensory issues....

Today I mentioned to Barney that Ice Age 3 is on at the cinema, and perhaps he would like to go see it sometime. I told him that we wouldn't go today as I knew that a sudden trip somewhere exciting like that would make him anxious. So I suggested he pick a day himself. He pondered for a moment and then said "I think I will wait for it to come out on DVD as I will be sick if I go to the cinema". I remember he had a severe panic attack with nausea last time he went to the cinema but I had presumed that was all down to the fact that it was an unplanned trip. I asked him what was it about the cinema that bothers him. His Dad suggested we plan it in advance, go really early so that he could get sat down and settled while all the lights were on and the cinema was empty. But still he didn't want to go. He said that it is the noise of the cinema that makes him feel sick. He is still reacting very badly to noises, going into utter panic if Emily cries. He wont let me play music in the car when we are out driving. If anyone shouts he panics and begs them to have a 'golden moment' or quiet time. I am wondering whether to purchase a pair of these ear defenders, as I have heard that some autistic children use them to protect their senses from loud or stressing noises. But I'm not sure whether he might become too dependant on them and start wearing them 24/7. And I don't want to buy them if they turn out to be a waste of time too.