Eye dominance or ocular dominance, is the tendency to prefer visual input from one eye to the other. Both hemispheres control both eyes, but each one takes charge of a different half of the field of vision, and therefore a different half of both retinas.
Approximately two thirds of the population is right-eye dominant and one third left-eye dominant; however in a small portion of the population neither eye is dominant.
You can download the Deakin Dominanat Eye test here (800k pdf)

Instructions:
Step1
Print the Deakin Optometry Dominant Eye Test page on your printer
Step2
Cut out the small square in
the centre of the page
Step3
Hold the page up at arms
length
Step4
With both eyes open focus
on a stationary object
Step5
While focussing on the object,
slowly bring the paper closer
until it touches your face
Step6
The eye which you have
over the opening is your
dominant eye