Don't beat yourself up, accidents do happen.
Shadow, my lab, has been more or less blind in one eye, from birth. Early on, it appeared she did see light, shadows, but that soon disappeared as well. The only way anyone could tell anything was different about her is because of the eye being blue. Otherwise she is full speed ahead.
Something to keep in the back of your mind. Keep a check on the eye ball pressure and appearance of the eye and how it rests in the eye socket. In Shadow's case, the pressure built quickly, it became an emergency situation and she had to have the eye removed. It isn't an easy surgery, full recovery for Shadow at least, took a while.