how do i tell if my duck is blind or deaf?

[duck luvr]

i have a white crested duck. she is super sweet, but i think that she might be either blind or deaf. she trips over stuff all the time, and doesn't respond when i walk towards her like the other ducks. any ideas on how i could test her for blindness or deafness without taking her to the vet?

 

[ChickenCanoe]

wave your fingers in front of her eyes and clap your hands.