My Pseudoexfoliation Patient Has Newly Discovered Pseudophacodonesis 5 Years Following Surgery. How Should I Proceed?
Pseudoexfoliation syndrome1 is a relatively common systemic disorder (up to 35% of patients over the age of 70) with well-known ocular sequelae. There is deposition of an ancillary fibrillary substance on all structures of the anterior chamber. Of course, pseudoexfoliation is highly associated with glaucoma and with complications during cataract extractions.2,3 The iris involvement may lead to poor pupil dilation, which further increases the risk for cataract surgery complications. The accumulation of pseudoexfoliation material is associated with a proteolytic process that probably leads to decreased tensile strength in the zonules.4 The capsule is also more brittle in pseudoexfoliation syndrome. Fortunately, with modern phacoemulsification techniques such as continuous curvilinear capsulorrhexis, chopping, and the use of capsular tension rings (CTRs) or capsule retractors, the surgical complication rate in these eyes has dropped dramatically.5
Late spontaneous dislocation of the entire intraocular lens (IOL) and bag complex in pseudoexfoliation was reported relatively recently.6 The dislocation may occur 2 months to 17 years postoperatively while the average is approximately 8.5 years after surgery. In our original report, most of the IOLs were made of polymethylmethacrylate (PMMA). Since that report, we have had more than 100 additional cases involving the entire gamut of IOL styles and materials, from single-piece silicone to 3-piece acrylics. To date, Nick Mamalis, and myself, as well as other investigators, have been unable to identify any risk factors other than the pseudoexfoliation to explain the late dislocation. The true incidence is unknown but is probably quite low. Therefore, I do not believe that any major change in surgical technique is advocated. We did not see this situation prior to continuous curvilinear capsulorrhexis with phacoemulsification, but the reduction in surgical complications allowing for capsular bag fixation may be enough to explain the situation.
Most patients do not present to the ophthalmologist until the entire bag-IOL complex has completely dislocated. However, some patients may note fluctuating vision and can present with pseudophacodonesis and minimal subluxation. Surgical management is certainly easier the earlier the patient presents.
Surgical management of the bag-IOL dislocation depends on the type of IOL. The dislocated bag-IOL can be explanted and, following an anterior vitrectomy, replaced with an anterior chamber IOL. There is no other choice but to do this for a silicone plate haptic IOL. However, IOLs with loop haptics can be suture fixated to either the sclera or to the iris, and this is my preference. A double-armed 9-0 polypropylene suture (Figure 49-1) can sclerally fixate each haptic by first ensnaring it with a lasso technique. One needle is passed through the bag and underneath the haptic before exiting through the ciliary sulcus. The second needle passes over the haptic before exiting alongside the first pass.
Figure 49-1. Placement of the haptic fixation with a 9-0 prolene suture.
The technique I prefer is to first bring the complex up to the pupillary plane,7 where vitreous and the surrounding capsular remnants are removed with a vitrectomy handpiece. I then use a double-armed 10-0 polypropylene suture to fixate each haptic to the peripheral iris with a modified McCannel suture (Figure 49-2).
Figure 49-2. Double-armed 10-0 polypropylene suture to fixate each haptic to the peripheral iris with a modified McCannel suture.
As a possible preventive measure, some surgeons advocate making a relaxing cut in the capsulorrhexis margin after the IOL has been implanted. Alternatively, this can be done postoperatively with the YAG laser. These strategies have not been tested by a randomized study and because this is such a late postoperative complication, it will take a long time to prove whether any preventive measure is effective. Others feel that implanting a CTR may help by more evenly redistributing and resisting capsular contractile forces (Figure 49-3). Although CTRs may help prevent capsule contraction, if bag dislocation is due to progressive zonular weakness, they probably will not stop the process. One advantage of having a CTR in the bag would be that it could be used to sclerally fixate the complex. A final option is to use a modified CTR, such as a Cionni I or II, which has an eyelet that can be used for scleral suture fixation.8 However, Miyake camera views in cadaver eyes show that inserting these can cause significant iatrogenic damage to the zonules.9 Because the incidence of late bag-IOL dislocation is probably low, one must carefully weigh the risks of inserting these devices against the theoretical benefit.
Figure 49-3. Scleral fixation of the lens with a CTR.
Late dislocation of the entire bag-IOL complex in pseudoexfoliation is unusual but not rare. Careful follow-up of pseudoexfoliation patients postoperatively is important and may afford an earlier opportunity for corrective surgery (Figure 49-4). Recommendations include making a capsulorrhexis that is relatively large (5.5 mm) and promptly treating any capsular phimosis with YAG laser relaxing cuts. Whether to routinely implant a CTR in every pseudoexfoliation patient is controversial and is probably not necessary.
Figure 49-4. Postoperative results.
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