We saw a paed opthamologists when our twins were around 2 years old at RCH. I am pretty sure that you can get their eyes checked a little earlier- ask your local doc.

my son used to go through stages of tripping over every time his feet would grow or be growing. I always knew to check his shoe sizing again when it started up as they were guranateed to be growing- he used to get bad growing pains to accompany this as well.
The tripping over would last a couple of weeks at a time, until he readjusted and taught his muscles to move again
also when kids grow, the muscle that has just grown has to be taught to operate correctly, so maybe a growth spurt could be to blame

otherwise might be worth seeing a OT- she may be having trouble with muscle tone or even the arch of her foot may be causing her to loose her balance
The Northern hospital have a clinic that you can self refer to to see an OT there.

She may be having trouble with depth perception as well- something to get checked as well. A way to check this is to put two objects the same colour on top of each other and see if she can pick up the top one. i.e a facewasher on top of the same colour towel.

if you have a concern- defintaely worth investigating it.
HTH and let us know how you go
odette