Misalignment of flexible iris hook retractors for small pupil cataract surgery: Effects on pupil circumference

A graphical method was used to assess the effect on pupil shape and circumf erence of various flexible iris hook malpositions. Results confirmed that a ll hook malpositions necessitate increased pupil stretching to create space to perform a capsulorhexis of a given diameter. This method also confirmed that the addition of a fifth hook to create a pentagonal pupil reduces pup il stretching by 17%. A simple method of marking the limbus before hook ins ertion to ensure equidistant hook separation and thus minimize pupil stretc hing is suggested.