When selecting an ergonomic mouse, it is important to consider the size of your hand and the size of the ergonomic mouse. An ergonomic mouse that is too large for your hand will cause your fingers to stretch when using it. Likewise, an ergonomic mouse that is too small for your hand will increase the level of gripping required to secure the mouse. Both of these factors can cause discomfort and pain in the wrist and forearm.
By simply measuring your hand size, you can quickly identify if you will require a large ergonomic mouse or whether a standard sized ergonomic mouse will be appropriate. To measure your hand size, simply take a measurement from the base of your wrist / palm to the top of your middle finger. If this measurement is 17.8cm or more then you are best suited to a large ergonomic mouse. If this measurement is less than 17.8cm then you are best suited to a standard size ergonomic mouse.