As a follow up: Just yesterday I purchased the Ikelite housing for the Olympus TG-5 camera, and find it is poorly designed. The shutter trigger and the zoom control are very stiff and not easy to operate; and as another Wetpixeler, Phil Rudin, mentioned the push buttons are very small, crowded and difficult to use with gloves or by feel. I have returned the Ikelite and will use the Olympus housing.
Other housings for the TG-5 are much too expensive, such as the Nauticam that goes for $800 plus. These past years I have used the Olympus housing for my TG-3 and TG-4 Olympus cameras and it is a good housing, reasonably priced and easy to use. But when open it must be kept very dry, and absorbent gel packs should be placed in it so it does not fog.
Also, it helps to mount the housing on a tray to hold it steady and and to hold lights or strobes.
http://wetpixel.com/forums/index.php?showtopic=60976- Tips to prevent fogging.