Description

• Intraoperative floppy iris syndrome (IFIS), a potential complication of cataract removal surgery, was first reported in 2005 and is thought to be mediated by atrophy of the iris dilator muscle (1).
  • Atrophy results from the use of some medications, particularly of the α-blocker tamsulosin.
• IFIS is distinguished by the intraoperative triad of flaccid iris billowing, progressive miosis, and iris prolapse through surgical incisions.
• The use of α-blockers, typically indicated for treatment of benign prostatic hyperplasia (BPH), is most likely to increase the risk of IFIS (1).
• Age is a common risk factor for BPH, prompting consideration for the use of α-blockers, and for the development of cataracts, prompting consideration for surgery, those combinations thereby raising the risk for IFIS (1).

Epidemiology

Incidence

• 0.5–2% of all cataract surgeries (1)
• Incidence of 60% among patients who are taking or who ever took tamsulosin (1)
• Occurs intraoperatively in 43–87% of patients who have ever taken tamsulosin

Prevalence
9 times more prevalent among males (2)

Etiology and Pathophysiology

• Hypothesized that α-blockers antagonize α-adrenergic receptors on the iris dilator muscle, leading to disuse atrophy and impaired mydriasis, setting the stage for iris dysfunction during cataract surgery
  • Persistent inhibition of the iris dilator muscle, for example, by an α-blocker, results in the muscle’s atrophy (1).
  • Atrophy causes loss of initial mydriasis during cataract surgery, subsequent iris billowing, potentially iris prolapse through surgical incisions (1).
• Use of autonomic drugs, such as α-blockers, is also associated with ocular anatomic changes affecting the iris and predisposing patients to IFIS (3).
• Effects of such medications on iris atrophy and/or anatomic changes can persist long after the implicated drug is discontinued (3).

Genetics
No known genetic predisposition for IFIS

Risk Factors

• Hypertension, but unclear if due to hypertension itself or the use of antihypertensive medications (4)
• Use of certain medications and/or supplements
  • Tamsulosin
  • Other α-receptor antagonists, including terazosin, doxazosin, alfuzosin, prazosin, and indoramin
  • β-Receptor blockers, including labetalol
  • Such antipsychotics as chlorpromazine, zuclopenthixol, and risperidone
  • Antidepressants, such as mianserin
  • Finasteride
  • Health supplements, notably saw palmetto
• Other predisposing factors
  • Selection of cataract incision site and intraoperative wound construction
  • Inadequate iris tonicity
  • Convex iris configuration
  • Small pupil size. A dilated preoperative pupil size of 7 mm or less increases the risk for IFIS, even in the absence of α-blocker use.
  • Shallow anterior chamber

General Prevention

• Offer patients a complete ophthalmologic assessment prior to starting an α-blocker.
• Give consideration to identification of cataracts and to surgical removal prior to starting α-blocker.
• Suspend use of α-blockers prior to surgery.
  • Such discontinuation is not always effective, as any prior use of tamsulosin can still predispose those patients to IFIS (3).
  • Discontinuing α-blockers can also cause urinary retention, which may be exacerbated during surgery (3).
• Use of preoperative atropine is controversial because evidence is lacking that it reduces the risk of iris prolapse (1).

Commonly Associated Conditions

None