http://www.macnn.com/articles/11/06/30/a.novel.approach.for.avoiding.wrist.strain/
MacNN Review: Evoluent VerticalMouse 4
updated 07:15 pm EDT, Thu June 30, 2011
A novel approach for avoiding wrist strain
Evoluent says that its innovative "vertical" multi-button VerticalMouse 4, which one holds and controls in a handshake style that doesn't twist the arm, is a superior way of resting your hand while using the mouse that avoids wrist strain. Does the vertical orientation eventually improve efficiency and proficiency in ordinary activities from surfing the web to playing games? Our full review has the answers.
Fresh-Faced Recruit
Joined: Mar 2010
they're great
I've used an Evoluent Vertical Mouse (third generation) at work since 2007, and it really helps reduce wrist strain. They're a little pricey, but I highly recommend them.