The way the Shinozaki Is able to awaken the Shino-Eye Is because Purevil developed a seal that allows one to awaken It, though Purevil can undo the seal at anytime If one was to form a Shino-Dojin, the seal will be undone and they will possess a real Shino-Eye.
Through loss, the user can awaken the Shino-Eye (Stage One). the effected of each stage carry over to other stages.
Shino-Eye Stage 1
Stage one of the eye offers an extreme enhancement of the users vision.
It's awakened through loss.
Shino-Eye Stage 2
Stage two of the eye offers an increased amount of strength.
It's awakened through immense emotional pain.
The final stage of the eye offers an hypnotic trance putting the target In dream-like state, If the target were to make direct eye contact with the user.
It's awakened through loosing a loved one or a close friend.