We just traveled through Heathrow last week, and security there confiscated my wife's contact lens solution (about 6 oz.) When I told the security person that saline solution was considered a medical solution and subject to an exception, she told me that there was no exception at Heathrow unless my wife had a prescription for her contact lens solution on her.
Contact lenses
I wear disposable contact lenses. Can I carry spare sets or solution in my hand baggage?
Yes, provided that each solution container or lens packet has a maximum capacity of
100ml or less and fits comfortably inside your single transparent liquids bag.
http://www.heathrowairport.com/heath...-security/faqs