Not putting cap on drops

[Eyeproblems]

Ok this feels like a silly question. I know i should put the cap on because of chance of infection, sometime im in a hurry and i forget.

The only thing I noticed as I am using alrex, and I dont know if its a result of just being open longer or not putting the cap on, but I picked up 2 a month and half ago. One i have been using and forgot to put the cap on. The other i had not opened.

The difference was pretty drastic when it came to effectiveness. The unopened one seemed to work much stronger then the opened one.

Is this due to me not putting the cap on?

[Nanerpus]

Do you shake the Alrex before putting a drop in? It's a suspension so it settles, and my doctor told me to make sure it gets a brisk shake before using. Not sure about the cap, but I'm sure the air getting to it for a prolonged period could possible alter it - but maybe not.