IFIS: question pre-cataract surgery patients about current, past use of meds

Issue: June 2006

ByLeonid Skorin Jr., OD, DO, MS, FAAO, FAOCO

Leonid Skorin Jr., OD, DO, FAAO, FAOCO [photo]
Leonid Skorin Jr.

It is now more important than ever to take a thorough patient medical history and review current and past use of medications. Optometrists who comanage cataract surgery patients with ophthalmologists can play a crucial role in informing the surgeon of those who may be at risk of developing intraoperative floppy iris syndrome (IFIS).

IFIS is a newly identified syndrome associated with the use of the commonly prescribed prostate drug tamsulosin HCl (Flomax, Boehringer Ingelheim) before cataract extraction surgery. This drug is used routinely in the treatment of symptomatic benign prostatic hypertrophy (BPH) and it is also prescribed off-label to treat urinary retention or urinary hesitancy in women.

Patients who develop these prostate and bladder problems are in the same age group as those likely to develop cataracts. BPH has been found to occur in 50% of men older than 50 and in 90% of men older than 85 (Ziada and Rosenblum).

Alpha-adrenergic receptor antagonists

Tamsulosin is just one of a number of systemic alpha-adrenergic receptor antagonists used to treat the urinary symptoms of BPH. All the drugs in this category improve urinary outflow by relaxing the smooth muscle tissue in the prostate and bladder neck.

There are three different alpha-1 receptor subtypes. Tamsulosin exhibits a high affinity and specificity for the alpha-1A receptor subtype, which is the receptor found in the prostatic and bladder smooth muscle. This high degree of receptor specificity is advantageous, as it is less likely to cause prostural hypotension — the primary side effect of taking an alpha-1 blocker, because these drugs can also relax the smooth muscle found in blood vessel walls. Because there is much less risk of postural hypotension with tamsulosin use, this drug has become the most frequently prescribed agent for BPH.

Other treatments for BPH

The other prescription medications used to treat BPH include terazosin (Hytrin, Abbott Laboratories), doxazosin mesylate (Cardura, Pfizer) and alfuzosin (Uroxatral, Sanofi-Synthelabo). All three of these drugs are much less selective alpha-1 blockers. Patients who use one of these agents are at a higher risk of experiencing postural hypotension. All three of these drugs can also cause IFIS.

Some patients also use a non-prescription herb known as saw palmetto (serenoa repens) as a natural treatment for BPH. The risk for developing IFIS while using this herb has also been suggested anecdotally.

How the drugs affect the iris

It has been shown in animal studies that the alpha-1A receptor subtype is the predominant mediator that causes contraction of the iris dilator’s smooth muscle (Yu and Moss). This appears to be the mechanism by which these urologic medications affect the iris smooth muscle’s contraction and tone.

What happens during surgery

The iris and pupil in patients who develop IFIS display three common factors:

Billowing of the iris with normal intraocular irrigation currents in the anterior chamber during cataract surgery.
Repeated prolapse of the iris to the phacoemulsification probe and the side stab incisions.
Progressive miosis during cataract surgery that is not prevented even with surgical intervention, such as partial thickness sphincterotomies or mechanical stretching of the pupil.

These at-risk pupils often do not dilate well preoperatively either. Those pupils that do not dilate well preoperatively tend to constrict considerably during cataract surgery. All of these factors have been shown to increase surgical complication rates.

Preoperative assessment

Optometrists who do the initial workup of a cataract patient should assess the patient’s pupil dilation. A poorly dilating pupil needs further investigation, such as a review of the patient’s current and past medications. This can help identify the use of one of the alpha-1 blockers, which would allow the ophthalmic surgeon to make an appropriate accommodation for that patient’s surgery and surgical time allotment. A past use of these drugs is important to ascertain because, even after stopping one of these agents, the iris abnormality and poor pupil dilation persists, possibly indefinitely.

In a large prospective study of 900 consecutive cataract surgery cases, investigators found an incidence rate of 2.2% (16/741) of IFIS, and they found that 15 out of the 16 patients (95%) with a floppy iris were taking or had previously taken the drug tamsulosin (Chang and Campbell). A retrospective study identified a 12.5% complication rate of torn posterior capsule associated with the syndrome (Chang).

New FDA labeling

Because of the potential surgical problems with the use of tamsulosin, the Food and Drug Administration (FDA) added a precaution in November 2005 to the labeling of this medication: “IFIS is a variant of small pupil syndrome and is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents, progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs and potential prolapse of the iris toward the phacoemulsification incisions. The benefit of stopping alpha-1 blocker therapy prior to cataract surgery has not been established.”

The labeling also alerts surgeons to be prepared for possible modifications to the surgical technique in such patients.

Cessation of therapy

Stopping the offending agent — the alpha-1 blocker, such as tamsulosin — does not appear to be of much value. The new FDA labeling reports instances of patients stopping these agents up to 9 months before their cataract surgery and still exhibiting IFIS. Finally, patients themselves are hesitant to stop using these agents. Many of these men obtain significant relief from their disease (BPH) when taking tamsulosin (or one of the other alpha-1 blockers) and are unwilling to discontinue the medication even for brief periods of time.

Techniques to avoid a floppy iris

Numerous variations to the cataract surgical technique have been recommended. These include pharmacologic methods such as using atropine sulfate 1% 1 week preoperatively to try to obtain a sustained mydriasis of the pupil. Other recommendations include the intracameral use of cyclopentolate, phenylephrine or epinephrine to maintain pupillary dilation during the cataract surgery.

IFIS: Intraoperative floppy iris syndrome with iris prolapse, billowing and intraoperative pupil constriction.

Image: Chang D

In addition, the use of high-density viscoelastic agents can be used during the operation to help push the iris tissue out of the surgeon’s way by mechanically keeping the pupil in a more dilated position. Although viscoelastic agents are commonly used during cataract surgery, the extreme high-density agents help maintain intraoperative space and hold back the iris.

Of course, these viscoelastic agents are more difficult to remove from the eye at the conclusion of the surgery, increasing the risk of a postoperative intraocular pressure spike. Premature evacuation of the viscoelastic agent intraoperatively may also lead to unexpected pupil constriction. In these cases, surgeons can help maintain viscomydriasis by using a low aspiration flow rate and low vacuum on their phacoemulsification instrumentation.

Other pupil management strategies include maintaining the pupil with a surgical device such as iris retractors or pupil expansion rings. Such a device must be placed before the capsulorrhexis creation. Because the capsulorrhexis is made early during the cataract surgery, the surgeon will need to decide to use either the iris retractors or pupil ring expanders before starting the surgery.

I have used the flexible iris hook retractors routinely in all patients who take any of the alpha-1 blocking agents for BPH. Since incorporating the iris retractors into my phacoemulsification procedure 11 months ago, I have experienced no surgical complications in these patients.

Once a surgeon gets comfortable and experienced using either the iris retractors or pupil ring expanders, the use of these devices adds only a small amount of time to the cataract surgery, but prevents a significant amount of anguish over potential complications. The billing code for use of these devices is 66982, cataract surgery, complex. The comanaging optometrist should become familiar with this new reimbursement code.

For more information:

Leonid Skorin Jr., OD, DO, FAAO, FAOCO, may be contacted at the Albert Lea Eye Clinic, Mayo Health System, 1206 W. Front St., Albert Lea, MN 56007; (507) 373-8214; fax: (507) 373-2819; e-mail: skorin.leonid@mayo.edu.

References:

Chang DF. Intraoperative floppy iris syndrome caused by Flomax. Paper presented at the ASCRS/ASOA Symposium on Cataract, IOL and Refractive Surgery, April 16, 2005, Washington.

Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg. 2005;31:664-673.

Yu Y, Koss MC. Studies of alpha-adrenoceptor antagonists on sympathetic mydriasis in rabbits. J Ocul Pharmacol Ther. 2003;19:255-263.

Ziada A, Rosenblum M, Crawford ED. Benign prostatic hypertrophy: an overview. Urology. 1999;53(suppl):1-6.