The Collaborative International Dictionary of English v.0.48:

Iridectomy \Ir`i*dec"to*my\, n. [Gr. ?, ?, iris + ? cutting out;
   ? out + te`mnein to cut.] (Surg.)
   The act or process of cutting out a portion of the iris in
   order to form an artificial pupil.
   [1913 Webster]

WordNet (r) 3.0 (2006):

iridectomy
    n 1: an eye operation that treats closed-angle glaucoma by
         surgical removal of part of the iris of the eye