Exactly how rare is central heterochromia?

How rare is sectoral heterochromia?

• I know about it an all, but I was just wondering if sectoral heterochromia is rarer than full heterochromia, and on a scale from say 1-10 how rare is it overall? And also out of curiosity, do people with any type heterochromia have more chance of needing glasses, as in, is it directly related?

• Answer:

  Sectoral heterochromia is rarer than full heterochromia. I'm not sure what the 1-10 scale would be compared to, but considering complete heterochromia is rare enough, sectoral heterochromia could be considered especially rare. I doubt it would have any correlation with needing glasses, since it is just a genetic coloring difference of the iris and doesn't directly affect the shape of the eye lens or the suspensory ligaments.