hi sparkles - the final test i used when my Kame passed away was... i touched his lower eyelid to see if he would respond. before he passed and was simply too weak to move, if my fingers got near his face, especially his eyes, he would still close that eye - because i think it didn't take that much energy to do this.
but if he is no longer alive, touching his eye(s) will get you no response. sorry to tell you this. but that's all i can think of so you can make a final conclusion. best of luck to you and here's hoping that he is still alive.