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By William J. Fishkind, MD, FACS; Alan S. Crandall, MD; and Ike K. Ahmed, MD, FRCSC
Cataract surgeons often must perform phacoemulsification in the presence of a functioning filtering bleb. In this situation, I strive to perform atraumatic surgery that avoids manipulation of the bleb. I create a clear corneal incision 90º away from the bleb. Performing phacoemulsification within the capsular bag, at the plane of the iris or posterior to it, minimizes trauma to the ostium of the bleb by lens particulates or the flow of irrigation fluid.
At the completion of the case, I carefully check the wound’s integrity. If there is any question of wound leak or excessive fluid flow through the bleb, I secure the wound with a 10–0 nylon suture.
Perioperatively, I administer 5-fluorouracil (5-FU; 5mg drawn up in a TB syringe as 0.1mL 5-FU combined with 0.1mL Xylocaine 1% [Astrazeneca LP, Wilmington, DE] with epinephrine) adjacent to and within the bleb. If the IOP is greater than 20mmHg postoperatively, I will administer 5-FU again at 1 week. The patient receives steroidal and nonsteroidal anti-inflammatory drops q.i.d. for 3 weeks postoperatively instead of the usual rapid tapering.
Alan S. Crandall, MD
I avoid causing trauma to a functioning bleb while creating the paracentesis and main incision by employing alternative fixation (eg, using the cannula with a viscoelastic), rather than my standard Fine Thornton fixation ring. I then perform my typical clear corneal phacoemulsification procedure. If the bleb is particularly thin-walled, I will use a low-flow technique, although usually blebs are not at risk. In the presence of a thick-walled, fibrotic bleb, I may need to increase flow to the bleb. In that case, I will occasionally perform intraoperative gonioscopy and open the internal ostium with a goniotomy knife, and/or I will administer an antimetabolite at the end of the procedure. I have used both 5-FU and mitomycin C (MMC) in such cases.
Postoperative hypotony is a possibility in eyes with functioning filtering blebs, and a hypotonous anterior chamber can lead to wound gape and endophthalmitis. I therefore always secure the wound with a 10–0 nylon suture and bury the knot.
IKE K. AHMED, MD, FRCSC
There is considerable variability in the literature concerning the short- and long-term effects of phacoemulsification on a functioning filtering bleb. Despite improvements in surgical technique, I believe bleb failure is a significant concern, and increased glaucoma medications are often required, particularly in patients who need low target IOPs.
A clear corneal approach (preferably temporal) is mandatory. The surgeon should not manipulate the conjunctiva with incisions or forceps, because surgery must be bloodless.
I like to place a dispersive viscoelastic plug over the internal ostium of the bleb in order to avoid irrigating lens cells into the bleb. A low-flow, low-vacuum setting will minimize large elevations in IOP intraoperatively, reduce irrigation into the bleb, and prevent bleb “blowout,” particularly in cases of cystic blebs.
It is important to avoid pupillary manipulation, which has been shown to increase the risk of bleb failure.1 If required, I first release any iridocapsular adhesions and then perform viscodilation with Healon5 (Advanced Medical Optics, Inc., Santa Ana, CA). I do not advocate pupillary stretching techniques, because they cause uncontrolled tears that can lead to further exudation and hemorrhage, which are risk factors for inflammation. When further management is required, I prefer using a pair of microscissors to make minisphincterotomies, which are much more controlled and do not produce a floppy iris, as does stretching. I like to use the bent Kelman tip (Alcon Laboratories, Inc., Fort Worth, TX) to direct waves of cavitation posteriorly, away from the angle of the eye, in order to minimize further trabecular trauma (as shown by Vasavada et al2).
Full cortical cleanup is mandatory, and the IOL should be placed in the capsular bag. I do not think it matters whether the surgeon chooses a third-generation silicone or foldable acrylic IOL. In the event of a large, posterior capsular rent, I will place the IOL in the sulcus. ACIOLs should be avoided. If anterior capsular support is lacking, an iris-sutured foldable IOL is the preferred option.
Postoperatively, patients should receive steroid drops q2h for the first 1 to 2 weeks, and then the medication should be tapered slowly. I also administer nonsteroidal anti-inflammatory drugs pre- and postoperatively. I watch for signs of impending bleb failure and perform injections of antimetabolites and/or bleb needling if indicated.
I am currently studying the safety and efficacy of the routine use of a subconjunctivally injected antimetabolite (ie, MMC, adjacent to the bleb) at the time of cataract surgery as a possible means of reducing the risk of bleb failure. The prospective, randomized study has a planned enrollment of 60 eyes. My hypothesis is that a perioperative injection of MMC helps the bleb withstand the insult of cataract surgery.
Section editor William J. Fishkind, MD, FACS, is Codirector of the Fishkind and Bakewell Eye Care and Surgery Center in Tucson, Arizona, and Clinical Professor of Ophthalmology at the University of Utah in Salt Lake City. He states that he holds no financial interest in the products or companies mentioned herein. Dr. Fishkind may be reached at (520) 293-6740; wfishkind@earthlink.net.
Ike K. Ahmed, MD, FRCSC, is Assistant Professor at the University of Toronto and Clinical Assistant Professor at the University of Utah in Salt Lake City. He states that he holds no financial interest in the products or companies mentioned herein. Dr. Ahmed may be reached at (905) 820-3937; ike.ahmed@utoronto.ca.
Alan S. Crandall, MD, is Professor and Senior Vice Chair of Ophthalmology and Visual Sciences as well as Director of Glaucoma and Cataract at the John A. Moran Eye Center, University of Utah, Salt Lake City. He states that he holds no financial interest in the products or companies mentioned herein. Dr. Crandall may be reached at (801) 585-3071; alan.crandall@hsc.utah.edu.
1. Casson R, Rahman R, Salmon JF. Phacoemulsification with intraocular lens implantation after trabeculectomy. J Glaucoma. 2002;11:429-433.
2. Vasavada AR, Mamidipudi PR, Minj M. Relationship of immediate intraocular pressure rise to phaco-tip ergonomics and energy dissipation. J Cataract Refract Surg. 2004;30:137-143.