There is a rather uncommon defect of the iris of the eye, in which a portion is absent,
causing pupil to somewhat resemble pupil of cat's eye. Called "coloboma". There used
to be an eye operation that produced such an effect.For glaucoma, I think. I once knew
a girl who had been born with a coloboma, and cruel kids called her "Cat-eye".
Here is URL with picture. http://www.eyeatlas.com/box/171.htm