Here is a cat which has heterochromia! I used to own her but the kid next door begged me to give it to her and my mom hates cats so I had no choice. :(
Shot this with a Canon EOS 700D and a Tamron 70-300 zoom lens. Nothing that special. I edited it a bit on lightroom to enhance the clarity but the color of her eyes are as bright as it is on the picture.