Abstract
Purpose: :
Intraoperative floppy iris syndrome (IFIS) is a condition seen during cataract surgery, marked by three distinguishing features: a flaccid iris stoma that billows in response to intraocular fluid currents, progressive pupil miosis despite preoperative pharmacologic dilation, and a propensity for the iris stoma to prolapse toward the wound and side-port incisions. This condition was first noted in patients who had been taking tamsulosin, a subtype selective 1-adrenoreceptor antagonist used to treat benign prostatic hyperplasia. This was thought to be a result of 1-adrenoreceptors being found in multiple areas of the body, including the lower urinary tract smooth muscle, iris dilator smooth muscle, and various arterioles. Although papers have mentioned the propensity of tamsulosin to cause increased pupil constriction preoperatively, none of them have documented the degree of pupil mydriasis impairment or the exact experimental settings.
Methods: :
We recruited 49 male patients over the age of 50 (who were either on an 1-antagonist or had never taken them before) seen over a twelve month period in university clinics. Pupil diameters were measured with an infrared pupillometer in mesopic (mean 610 lux) and scotopic (mean 0.8 lux) settings. Two drops each of 2.5% phenylephrine and 1.0% tropicamide were placed in each patient’s right eye. Following dilation, pupil diameters were measured again.
Results: :
No statistically significant difference was found in pupil mydriasis of patients taking 1-antagonists versus those who were not. The length of time that the patients had been taking the medication also did not have a statistically significant effect on pupil mydriasis. When comparing tamsulosin patients to other 1-antagonist patients, no significant difference was found in pupil mydriasis either.
Conclusions: :
Previously, it had been hypothesized that a majority of patients taking 1-antagonists would experience preoperative impairment of pupil dilation. It was those patients that needed to be carefully attended to during eye surgeries, specifically cataract surgeries. However, none of the patients in this study had significantly decreased pupil diameters compared to control patients. If current literature is to be believed, these patients are still at risk for IFIS. Thus, preoperative pupil dilation in patients taking 1-adrenoreceptor antagonists cannot and should not be used as a sole marker for intraoperative performance.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • iris • cataract