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"Pseudoexfoliation eyes need special care, and surgeons must consider the multiple pathologic alterations in these eyes in order to get good results. However, each eye must be approached individually, taking into account general considerations for operating when pseudoexfoliation is present, the preoperative and intraoperative findings of the specific case, and your own personal experience," said Dr. Kuchle.
"Cataract surgery in the context of pseudoexfoliation remains a delicate operation, even if advances in surgical technique and technology have contributed to a more comfortable surgical environment. Often, it is experience that enables the anticipation of complications and allows them to be prevented, and good results have to be measured over a long period, not just in the first few months after surgery. Therefore, the approach to surgery has to be planned with the future in mind," noted Dr. Hachet. General anaethesia Given the complexity of these cases, it may be prudent to perform the surgery under general anaesthesia, especially in eyes with truly fragile conditions, explained Dr. Galand. There is no reason to hesitate about using general anaesthesia if it seems indicated because the medications in current use are short-acting and permit surgery to be performed in an outpatient setting," he said.  Poor mydriasis, which is a prominent feature of pseudoexfoliation eyes secondary to exfoliation deposits on the iris, presents a challenge to cataract surgeons, especially considering that a sufficient pupil size is important to facilitate creation of an appropriately large capsulorhexis and to minimise forces exerted within the eye against the zonule throughout the procedure.
Simple stretching may be enough to achieve adequate pupil enlargement in some cases, or it may be accomplished with injection of a high viscosity viscoelastic against the pupillary margin. Surgeons using the latter technique need to recognise that the presence of such a material in the anterior chamber may make the capsulorhexis more difficult by counteracting the force of the forceps and thereby increase the risk of premature tears. Furthermore, once the viscoelastic is aspirated, the pupil will retract. Use of a divergent phacoemulsification manipulator that enables displacement of the pupillary edge back away from the axis of the phacoemulsifier can also provide an adequate solution, especially for the surgeon using a "divide and conquer" technique, Dr. Hachet said. However, all of the speakers advocated use of iris hooks, either plastic or metallic, as necessary. They can be placed during any phase of the surgery, and have the advantages of being easy to use and devoid of any untoward cosmetic after-effects. Dr. Hachet cautioned against performing sphincterotomy, which results in persistent dilatation and poor postoperative cosmesis, and he recommended against using a circular plastic dilatator to push the pupil rim aside. Insertion of that device is often delicate and it may worsen zonular distension and existing endothelial alterations," he explained. Irido-capsular synechiae are often present in eyes with pseudoexfoliation, but they can be easily divided through injection of a viscoelastic and the use of a spatula, Dr. Hachet said. The major intraoperative and postoperative risks presenting to the cataract surgeon are zonular dialysis and IOL dislocation, respectively. Placement of a capsular tension ring (CTR) can help address both of those issues, although it does not have to be used routinely. As noted by Dr. Galand, it may even be possible to use the IOL haptic as a capsular tension segment. However, all of the speakers agreed that a CTR should be placed without delay if zonular instability is manifest intraoperatively, but they all cautioned about the intricacy of that procedure. Use of CTRInsertion of the CTR should always be performed over a bag fully expanded by viscoelastic, and surgeons must always keep in mind the risk of a massive tearing of the zonulae. Even though the ring distributes force over the circumference of the capsular bag, it does not mend existing zonular defects, and if they are too significant, the ring will be ineffective and perhaps even dangerous," Dr. Hachet said. He added that insertion of a rigid CTR sutured in the ciliary sulcus is an alternative when zonular lesions are present. Creation of a generously-sized capsulorhexis is another important feature of cataract surgery in pseudoexfoliation eyes because a small capsulorhexis may be associated with both increased zonular stress intraoperatively and an increased risk of anterior lens capsule contraction postoperatively. 'The surgeon should not hesitate to enlarge the anterior capsule up to or even beyond the pupil margin opening using a capsular scissors or capsular forceps," said Dr. Galand. To minimise the risk of zonular dialysis during lens removal, it is also critical in these cases to rotate the nucleus and bring it forward out of the bag early. In all pseudoexfoliation cases, avoid working for any prolonged time with forces within the capsular bag, he stressed. To further avoid placing undue traction on the equator of the capsular bag, irrigation and aspiration should be done in the central safe zone, and its precision may be facilitated using a single way cannula with a push-pull manoeuvre. Placement in the fornix can also be helpful to reduce the amount of traction and capsular force exerted, said Dr. Galand.
Polishing of the lens capsule should not be done, but residual small fibres of cortical material can be removed using a waterjet manoeuvre or with suction vacuum cleaning. When placing viscoelastic for the IOL implantation, use of an agent that is not highly viscous is preferred to facilitate implant unfolding. "Surgeons might also consider that a lesser quantity of viscoelastic may be needed with the use of cartridge and injector delivery systems. In any case, meticulous attention should be directed to completely remove the viscoelastic from these eyes which are already predisposed to postoperative IOP elevations," Dr. Galand said. Choosing an IOL Selection of an appropriate IOL must take into account a number of the special features of pseudoexfoliation eyes. First, there are increased risks of late IOL decentration and dislocation as a consequence of zonular weakness combined with the occurrence of more pronounced anterior lens capsule contraction in pseudoexfoliation eyes. In addition, pseudoexfoliation may be associated with extensive breakdown of the blood-aqueous barrier. PCO also develops more frequently in pseudoexfoliation eyes relative to normal, healthy eyes. Against that background, Dr. Kuchle provided some general principles for IOL selection, and based on his review of the literature and personal experience, he indicated preferences for IOL material and design. In all cases, small incision surgery with implantation of a foldable IOL is desirable to minimise further induction of blood-aqueous barrier breakdown and the accompanying increased risks for postoperative complications. All of the various materials used for foldable IOLs appear to carry less risk of blood-aqueous barrier breakdown compared with rigid IOLs, he noted. The implant chosen, however, should be of an adequate size to achieve a large area of contact in the fornix of the capsular bag, and it should feature haptics of sufficient size and stability to support the capsular bag equator. " Therefore, I would strongly discourage use of plate haptic design or accommodative IOLs in patients with pseudoexfoliation. Overall, open loop haptics are probably preferred, and PMMA may be better than Prolene, according to some studies," Dr. Kuchle said. From the standpoint of PCO development, an optic with a sharp edge design is clearly preferred, but the effect of different optic materials on PCO risk need also be taken into account. Based on that feature, Dr. Kuchle indicated he considers hydrophobic acrylic the material of choice followed by silicone, and either of those would be preferred over IOLs with a hydrophilic acrylic (hydrogel) optic. "All of these options have favourable profiles with respect to their potential for inducing blood-aqueous barrier breakdown, and both hydrophobic acrylic and silicone are associated with a low rate of PCO, but hydrophobic acrylic has an additional advantage as it causes the least amount of capsular contraction," Dr. Kuchle said. Addressing phacodonesis Alterations of the zonular apparatus and its insertion into the ciliary body and lens raise the risks of phacodonesis and vitreous loss. The finding of phacodonesis presents the need for additional modifications in surgical technique and influences IOL selection, said Dr. Hachet.If vitreous is present, a wide anterior vitrectomy should be performed early, even before viscoelastic injection, in order to limit anterior migration of the remaining vitreous. With low phacodonesis, insertion of an implant in the bag, either the Corneal or Arkoflex Physiol 360SE, is an option, Dr. Hachet said. If there is marked phacodonesis, phacoemulsification must be performed in the anterior chamber, and the surgeon should implant either a posterior chamber IOL in the ciliary sulcus or use an anterior chamber lens, such as an Artisan IOL. It may be possible as well to implant a posterior chamber IOL sutured through the sclera, but that is associated with less reliable long-term stability, he added. Albert Galand MD Michael Kuchle MD
Etienne Hachet MD
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