Floppy Iris Syndrome

Basics

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).

Incidence

Prevalence
9 times more prevalent among males (2)

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

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

ALERT

Patient use of tamsulosin, among other α-blockers, is associated with a significant increase in the risk for the development of IFIS (1).
Primary care physicians, mindful of a 2007 study that showed that 96.8% of primary care physicians surveyed in the United Kingdom were unaware of IFIS, should take the risk of IFIS into account when prescribing α-blockers, inquire about cataract history, advise patients to inform ophthalmologists of the use of α-blockers (5).
Despite attempts to educate physicians by the American College of Physicians and the American Academy of Family Physicians, a small 2014 San Francisco study indicated that 90.1% of respondents failed to ask patients about cataract symptoms before starting an α-blocker (5).

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).

None

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