Any kind of of tape is fine.
Typically, the small amount of fluid (10-100cc) is not enough to properly irrigate the eye(s). Sterile water or saline is not required, expensive and expires. Tap water is perfectly fine and normally easily found.
If you really want to include something for the eyes (or wound irrigation), just buy a bottle of drinking water and stick it in there. It can also be used for drinking water in survival situations. Maybe include one of those folded survival blankets too.
So I will start with the list of things I already have saved from surfing this sub
http://www.amazon.com/gp/product/B00A3Z44RW/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
These are great to put over your tent to keep the light and heat out in the morning so you dont wake up in a sauna at 7am
And finally, I will never attend another festival again without this stuff, it is a foaming body wash that does not require water. We use it at my work all the time for bed baths and whatnot, so I thought I would try it for a festival and it works quite well. It doesnt get you as clean as a normal shower but this and baby wipes can keep you feeling fresh the whole weekend (just dont use it on hair)
http://www.amazon.com/gp/product/B00K2SM512/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1