A dominant white cat with blue eyes [is said][1] to be at high risk of being deaf. (Here the "dominant" refers to the white color gene, not behaviour.) In case of a white cat with odd eyes, the ear on the side with the blue eye may be deaf, though in some rare cases an odd-eyed cat can also be totally deaf.

![My cat with Heterochromia iridum][2]  

That's one of the cats I have. Totally white fur, pink pads and ears, and odd eyes. I have tested her for hearing and it seems quite obvious that she can hear, but does she hear only with one ear or two? How would I test if she's deaf in the ear on the blue side?


  [1]: http://www.messybeast.com/whitecat.htm
  [2]: https://i.sstatic.net/CVPl0.jpg