Study identifies pupil dynamics that may contribute to intraoperative floppy iris syndrome

This prospective study describes a new method to acquire quantitative pupil measurements and identifies certain preoperative pupil dynamics associated with the use of alfuzosin and tamsulosin that may contribute the development of intraoperative floppy iris syndrome.

According to the most recent white paper by the American Society of Cataract and Refractive Surgery, there is a strong association between intraoperative floppy iris syndrome and tamsulosin, a selective α1A- and α1D-adrenergic receptor antagonist commonly prescribed for the treatment of benign prostatic hyperplasia. Tamsulosin has also been associated with a 2.3-fold increase in the postoperative cataract complication rate, and other α-antagonists, such as doxazosin, terazosin, alfuzosin, and labetalol, have been associated with intraoperative floppy iris syndrome.

In light of these findings, the authors used the new digital portable NeurOptics pupillometer to assess dynamic pupil function before and after preoperative dilation in 40 patients taking tamsulosin or alfuzosin and in 25 controls.

They confirmed the association of tamsulosin and alfuzosin with increased tendency for intraoperative floppy iris syndrome. In pre-dilation measurements, both induced a significant decrease in the maximum pupil diameter, percentage of pupil size reduction after stimulation, and constriction velocity. In post-dilation measurements, only tamsulosin induced a significant decrease in maximum and minimum pupil diameter, while alfuzosin did not alter any pupil characteristics.

They write that reduced pre-dilation constriction velocity could indicate a greater likelihood of developing intraoperative floppy iris syndrome. This characteristic, in combination with an initial small maximum iris aperture and poor postdilation mydriasis, may represent a triad of features that could enable the surgeon to identify the possible occurrence of intraoperative floppy iris syndrome preoperatively with increased accuracy through the use of a NeurOptics electronic pupillometer.