Vet Andrew Miller, who removed what was left of the eye, said the injury looked suspiciously like a gunshot wound. There were no scratches or other injuries that might have been left by an attack from another animal, or signs of an injury caused by a barb.
His Kauri Veterinary Hospital treated two or three gunshot wounds in pets each year, he said.
The Northern Advocate was told by another cat owner in the Fairway Drive area their cat had also been injured in the past week, with what looked like shotgun pellets in its back.
Before Ms Noble found a vet who could carry out the emergency surgery on a payment plan, she had been advised by others to have Shadow put down.
"I couldn't do that, she's my baby," she said.
Mr Miller said cats managed well with only one eye, although it could take some time for them to adapt.
Shadow went home from the vet's surgery yesterday and Ms Noble said she would have to build up the courage to let her pet outside again.
"Fortunately, she's an inside cat. She hardly ever goes away from the house," she said.
-Anybody with information on how the cat got its injury can contact Whangarei police on 430 4500.
