My idea was simple but I'm thinking it exists already now.
I use contacts and from the very beginning was told it's wise to carry them around with you at all times in case you need to take them out in an emergency. But, there is no lens carrying device that is convenient, nor do they sell small bottles of lens fluid. So I thought I'd make a travel pack for that, but small and fits anywhere.
But, since the airports started tightening security in relation to liquids, a few lens liquid companies have made some small bottles and travel kits. I know I thought of it before I saw them in shops. I still think there is a niche for a decent lens travel pouch.
Another idea is a pen that dispenses paint instead of ink. I made one for myself for my artwork - I needed a device that would make writing with paint easy. It only has one problem, you can't stop the paint running when you want. So it gets messy. Basically I use the outer tube of a pen (discard the inside bits), stick it in a can of paint so the tube fills up then I take it out and stopper the end. When I want to use it I remove the stopper and the paint flows! I love it
