One pupil larger than the other

I'm curious if anyone has any experience with cat eyes like this, or if anyone knows why it occurs. One of my Pippa's pupils is larger than the other. She has had this since I adopted her in January.

I know that large, dilated pupils can indicate trauma, but that does not seem to be her issue. She does not appear to look like the cats in the photos I've seen of that. It may be possible, however, because I do not know much about her history.

The pupil does dilate, but one side seems... off. It is almost triangular. The more dilated the eye is, the less obvious the angle is. She can see out of that eye, but we wonder if her vision may be slightly limited. Her vet doesn't think it seems to be a problem. I wondered if it could simply be due to inbreeding or something along those lines. It's very clear in the photo which pupil I mean:


Not the best photo, but you can see that her pupils do dilate- it is not obvious in low light:

I had always thought that it may indicate some sort of trauma as well.  Perhaps she had something happen as a wee kitten?. 

She is a beauty though and certainly looks healthy