Find poles of a complex expression involving modified Bessel function

Hey guys!

How to find zero locations of a complex expression involving modified Bessel Function in complex plane? My complex expression is the following:

z^2*(1-BesselI(0,z)^2/BesselI(1,z)^2)+C

where BesselI(0,z) is modified Bessel Function of first kind of order 0 and BesselI(0,z) is modified Bessel Function of first kind of order 1. C is a constant,

In other word, I am looking for poles of a complex expression whose denominator is the above expression.

Thank you very much!!