Severe Iris Pigment Epithelium Desquamation

After Routine Cataract Surgery

Kendall R.B. Dobbins, MD

Geisinger Medical Center

Author has no financial interest

Purpose:

• To present a unique case of severe iris pigment epithelial desquamation following routine cataract surgery and to investigate whether the case could be an unusual variant of toxic anterior segment syndrome (TASS).

Methods:

• A 66 year-old woman with no pre-operative history of pigment dispersion syndrome underwent routine clear-corneal cataract surgery OS. Below is an image of the iris OD to provide a sense of the pre-op status of the iris OS.

Methods• At the one-day post-operative visit, there were 4+ diffuse iris

trans-illumination defects, 4+ iris pigment cells suspended in the anterior chamber, a significant amount of pigment cells coating the corneal endothelium and iris stroma, and pigment dispersion-related ocular hypertension with an IOP of 31 OS (see images).

Methods• The intraocular lens remained well-positioned within the

capsular bag (see images), ruling out a mechanical cause for the severe pigment dispersion. An investigation was undertaken to try to determine the etiology of the event and to clarify whether or not the case could be a variant of Toxic Anterior Segment Syndrome (TASS).

Results

• There was nothing unusual about the substances used in the eye or on the surface of the eye– Substances in the eye:

• 500cc BSS with 0.5cc Epi 1:1000 (Alcon)• Amvisc Plus (B+L)

– Substances on the surface the eye:• BSS 15cc (Alcon)• Povidone Iodine 5%--diluted from 10% solution by

hospital pharmacy under sterile conditions (Aplicare)• Prednisolone acetate, Gatifloxacin, and Timolol GFS

drops immediately post-operatively

Results

• However, further investigation of the cleaning and sterilization processes at our ASC revealed that enzymatic detergent had been used when cleaning instruments in the ultrasonic cleaner and tap water had been used to flush the hand-pieces, both of which were considered potential sources of endotoxin.

Results

• Literature Search– Brouzas et al. Severe toxic effect of methylene

blue 1% on iris epithelium and corneal endothelium. Cornea 2006 May;25(4):470-1.

– Monson, Mamalis, Olson. Toxic anterior segment inflammation following cataract surgery. JCRS 1992 Mar;18(2)184-9. 3 cases with widespread corneal edema, fixed pupil, and significant iris atrophy.

– No reports of isolated acute pigment dispersion S/P routine Phaco with IOL (without corneal edema).

Results

• Discussions with the head of the U.S. TASS task force deemed that this case was unlikely to be TASS since the corneal endothelium remained essentially intact while the iris pigment epithelium was so severely affected. In the two years following this case, there have been no further repeat cases in our department.

Conclusion

• There are no reports of isolated acute diffuse non-mechanical pigment dispersion without associated corneal edema after routine cataract surgery, making this case very unique. While the etiology of this event remains unknown, this case demonstrates how a thorough evaluation of the sterilization process of cataract surgical instruments should be performed at all surgery centers.

Conclusion

• Changes in sterilization in our ASC:– Instruments placed in ultrasonic cleaner

without enzymatic detergent (thought to be a possible source of endotoxin).

– Handpieces are flushed with sterile distilled water instead of tap water.

– Instruments put through washer/disinfector machine daily.