Firstly, my eye doctor told me not to decant the fluid into other bottles. Contact lens liquid is sterile, and the cap is designed to keep it that way. If you fill it into another bottle you risk it loosing it's sterility.

Secondly, not all brands are sold in small bottles. I use AO Sept, which is not available under 100ml. I have had serious issues with other cleaning fluids such as ReNu. Unfortunately, I have no choice for some airports as I refuse to check luggage. For quite some time already, I have been alternating what I take with me depending on the airports I go through.

It would be very useful to have a "redlist" of airports confiscating contact solution over 100ml versus those that don't. (Greenlist?)

I also think somebody should take this topic on and do something. There should be transparency in the rules, with an explicit exception for contact lens liquid and consistency in application of the rules at all airports of the world that apply liquid restrictions.

Here my "redlist":

Amsterdam
All of UK
Brussels
Belgrade

"Greenlist":

All of Switzerland, Germany and Austria
Paris CDG
Ljubljana
Zagreb
Warszaw

Maybe we can build a comprehensive list together.