Search Photos by Keyword in iOS

I've added keywords to all my photos on my Mac. They are hierarchical - e.g. Friends.Old.Smiths.John and on the Mac I can find photos by entering keywords into Spotlight. When I synch them to iPhone and iPad there doesn't seem to be a way to search by my keywords - I assume that Apple strips out my keywords before adding its own when it transfers the photos to iPhone/iPad. If anyone knows a way to transfer photos with keywords or know of an app that does I'd appreciate more information.