Looping Through Tw-dimensional Array

I need to loop through a two-dimesnional array (x,y) until a value in x is empty or the end of the array is reached, whichever comes first. Example array:

Dim myArray(4,1)

myArray(0,0) = "part 1"
myArray(0,1) = quantity
myArray(1,0) = "part 2"
myArray(1,1) = quantity
myArray(2,0) = "part 3"
myArray(2,1) = quantity
myArray(3,0) = ""
myArray(3,1) = quantity
myArray(4,0) = "part 5"
myArray(4,1) = quantity

In the example above, the loop should stop once it determines myArray(3,0) is empty. If myArray(3,0) was not empty, the loop would continue until the end of the array was reached. Anybody have a code example to do this?