Iris Prolapse

Iris prolapse can create problems during surgery and can lead to iris damage which can be dysfunctional.

Iris prolapse typically comes from a wound which is too short or from an iris which is floppy and/or poorly dilated.  The actual prolapse of the iris usually occurs during hydrodissection and can create transillumination defects, loss of iris tissue, iridodialysis, and hyphema.   It is important for eye surgeons to know how to preserve the iris when prolapse occurs and i suppose, more importantly, to prevent it from occuring in the first place.


     

Wound too short.  When the wound is too short one of the best options to prevent iris prolapse is to simply close the short wound and move to another site.  Often however moving to another site is difficult as the brow, a bleb, or the surgeons handedness get in the way of this solution.   A nice simple solution is to place a single iris hook under the incision to pull the iris under the incision preventing prolapse.  If the pupil is also small it can be useful to place 4 hooks in a diamond configuration with one hook under the wound to both prevent iris prolapse and to open the small pupil.  Iris rings such as the Malyugin ring can be used also but if the wound is very short the iris can still prolapse with the ring. 

Floppy iris.  When the patient is at risk for a floppy iris (intraoperative floppy iris syndrome) from an alpha blocker (especially Flomax or tamsulosin) or some other cause (eg ischemia ) it may be best to prevent iris prolapse with iris hooks or a Malyugin ring especially if the pupil is small.  The most common time for iris prolapse is during hydrodissection when the fluid wave passes around the lens and out the eye taking the iris out too.  Excessive and especially dispersive viscoelastic can make hydrodissection more risky for iris prolapse.  I like to remove viscoelastic above the lens prior to hydrodissection to help prevent this complication.   Gentle rocking of the lens will help to release trapped fluid behind the lens which will lower the pressure and deepen the anterior chamber.

Repositing the iris.  When iris prolapse occurs the emphasis should be on preserving the iris and preventing further prolapse.  The first step following prolapse is to use the paracentesis to remove fluid pressure from within in the eye which is pushing the iris out.  Then using a viscoelastic cannula gently reposit the iris.  After the iris is back into position consider placing an iris hook under the wound to keep the iris from further prolapse.   below you will find a video showing these techniques  Rarely, iris prolapse willl occur when you face posterior pressure from a choroidal hemorrhage, choroidal effusion, or misdirection of aqueous.

References:

Chang DF, Braga-Mele R, Mamalis N, Masket S, Miller KM, Nichamin LD, Packard
RB, Packer M; ASCRS Cataract Clinical Committee. ASCRS White Paper: clinical
review of intraoperative floppy-iris syndrome. J Cataract Refract Surg. 2008
Dec;34(12):2153-62. 

Chang DF. Use of Malyugin pupil expansion device for intraoperative
floppy-iris syndrome: results in 30 consecutive cases. J Cataract Refract Surg.
2008 May;34(5):835-41.

Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with
tamsulosin. J Cataract Refract Surg. 2005 Apr;31(4):664-73.