Carpal tunnel and other repetitive stress injuries can be a debilitating and chronic ailment, ruining not only your professional life, but also the overall quality of life, if unattended. Usually just some simple ergonomic changes to your setup, such as a switching out to a different keyboard or using a properly sized task chair, can make a significant difference between pleasure and comfort. But don't forget the mouse.
In art and design classes, students are taught to illustrate with a pen or paintbrush using their arms and wrist together in full motion, not just in tiny movements with their hands. This technique allows for great range of comfortable motion for long periods of time (alongside creating better strokes), and in similar fashion, the SmartFish ErgoMotion Laser Mouse design initiates greater arm movement through a floating and pivoting design.
The SmartFish mouse is mounted ontop of a 3D axis pivoting base that glides along like any other mouse. The increased range supposedly decreases repetitive stress injuries, increases circulation, naturally keeps the user's wrist floating above the surface and was developed in conjunction with the orthopedics-specialty, Hospital for Special Surgery (HSS) in New York. Whether this is the best ergonomic input solution for you is not clear, as we've noted some people swear by a pen and tablet, while others love touchpads, and others simply like a stationary trackball...a wholly subjective comfort and fit issue.
At $50, and both Mac and Windows compatible, the SmartFish mouse seems like an affordable option to investigate if you're suffering from chronic pains caused by daily and extended use. Just be sure to make sure everything else is also setup correctly in accordance to proper ergonomics, because repetitive injuries in an office or home office are often caused by a variety of mitigating factors.