Perspectives in Lens & IOL Surgery
Surgeons report—a new small pupil syndrome caused by Flomax
by David F. Chang M.D. and John R. Campbell M.D.
I. Howard Fine, M.D. |
You perform your usual method of mechanical pupil stretching, perhaps adding partial thickness sphincterotomies. This affords a large enough pupil to perform a capsulorhexis.
Commencing bimanual MICS
in a Flomax patient with a well
dilated pupil.
Pupil constriction accompanies
iris billowing and prolapse to
1.2 mm phaco incision.
Progressive intraoperative
miosis with prolapse to both
1.2 mm incisions.
Poor pre-operative dilation
despite discontinuing Flomax
for 2 weeks.
Iris retractors maintain
adequate pupil size.
Diamond configuration
improves sub-incisional
access to epinucleus.
Note iris prolapse to
side port incision.
Following IOL insertion and
retractor removal, pupil
billows, prolapses, and
constricts during removal
of viscoelastic.
Strong tendency to prolapse
despite stopping Flomax
preoperatively and using
iris hooks.
Source: David F. Chang, M.D.
Our suspicion is that you have probably encountered such a case.
Having found no such description in the peer-reviewed literature, we have named this condition the intra-operative floppy iris syndrome (IFIS). It is characterized by repeated incisional prolapse of a floppy iris, causing progressive intra-operative miosis that is not prevented by sphincterotomies and mechanical pupil stretching. The pupil often dilates poorly pre-operatively.
Study particulars
We have just completed both a retrospective and a prospective study of IFIS, the results of which have been submitted for publication and will be reported at the next ASCRS•ASOA symposium and congress (April 15–20, 2005, Washington, D.C.).
In these two series of more than 1600 combined patients, we found overwhelming evidence that IFIS is caused by tamsulosin hydrochloride (Flomax, Boehringer Ingelheim GmbH, Germany), a systemic alpha-1 antagonist medication. This drug relaxes the smooth muscle in the bladder neck and prostate, improving urinary flow in patients with symptomatic benign prostatic hypertrophy (BPH).
Flomax is highly selective for the alpha-1A receptor subtype that predominates in the prostate. It is therefore more uroselective compared with other alpha-1 blockers for BPH, such as Hytrin (terazosin hydrochloride, Abbott Laboratories, Abbott Park, Ill.) and Cardura (doxazosin mesylate, Pfizer, New York). For this reason, it is currently the most commonly prescribed medication for BPH. Interestingly, we did not find that Hytrin or Cardura caused IFIS.
Our review of the pharmacologic literature suggests that the same alpha-1A receptor subtype is also present in the iris dilator smooth muscle.
We postulate that prolonged pharmacologic blockade results in loss of normal iris dilator smooth muscle tone. This deficient tone produces the floppy iris behavior caused by normal intraocular fluid currents during surgery.
Clinical implications
There are several important clinical implications of this association. First, pre-operatively, male patients should be questioned about Flomax use, particularly if the pupil dilates poorly. Because of its long half-life, we advise temporarily stopping this medication for two weeks before cataract surgery. In our experience, we found that this improves but does not eliminate the floppy behavior of the iris. This suggests a more lasting effect of Flomax on the iris dilator smooth muscle.
With respect to surgical technique, one should pay particular attention to proper incision construction, and avoiding excessive injection of an ophthalmic visco-device or hydrodissection fluid.
We strongly recommend the use of iris hooks or an iris expansion ring to maintain an adequate surgical pupil diameter. In general, these measures are less commonly used for small pupil management because of the additional surgical time and cost involved.1 They are also difficult to insert without ensnaring the capsulorhexis once the latter has been completed.
Therefore, anticipation of IFIS allows the surgeon to reconsider their usual methods of small pupil management in favor of self-retaining pupil expansion devices inserted prior to capsulorhexis initiation. If disposable iris retractors are used, we favor the diamond configuration recommended by Oetting and Omphroy.2 Finally, we have tried bimanual microincisional phaco in these IFIS eyes, expecting that the tighter incisions might prevent iris prolapse. If the pupil is reasonably well dilated, or if iris hooks are used, the ability to keep the irrigation flow more consistently anterior to the iris plane seems to reduce iris billowing and prolapse. However, if the pupil is small, we found that billowing and prolapse still occur, even through the tighter 1.2 mm micro-incisions.
In conclusion, IFIS is a newly described small-pupil syndrome caused by a medication that is commonly used in the elderly male population. Because of the higher risk for posterior capsule rupture and iris trauma associated with IFIS cases, we believe that recognizing and anticipating these cases will be important in enabling surgeons to reduce the complication rate.
Editors’ note: The authors have no financial interest in any products mentioned.
About the Authors
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David Chang, M.D., clinical professor, University of California, San Francisco and in private practice in Los Altos, Calif. Contact him at 650-948-9123, fax 650-948-0563, dceye@earthlink.net
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John R. Campbell, M.D. is in private practice in San Rafael, Calif. Contact him at 415-454-5565, fax 415-454-2957, JRC@MarinEyes.com |
References
1. Akman A, Yilmaz G, Oto S, Akova Y. Comparison of various pupil dilatation methods for phacoemulsification in eyes with a small pupil secondary to psueudoexfolication. Ophthalmology 2004;111:1693-1698
2. Oetting TA, Omphroy LC. Modified technique using flexible iris retractors in clear corneal surgery. J Cataract Refract Surg. 2002; 28:596-598
