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April 2012 Scleral-fixated PCIOLs: In the absence of support by Enette Ngoei EyeWorld Contributing Editor Study reports complications common in scleral-fixated PCIOLs I n the absence of capsular sup- port when implanting an IOL, a surgeon has three options: anterior chamber implantation of the IOL or posterior implan- tation of the IOL using either the sutured iris-fixated technique or the scleral-fixated technique. An unacceptable rate of compli- cations associated with closed-loop anterior chamber IOLs (ACIOLs) in the 1980s brought about a shift toward scleral fixation of a posterior chamber IOL (PCIOL). A study published in the Journal of Cataract & Refractive Surgery looked at the long-term visual outcomes and complications of implanting scleral-fixated PCIOLs. Conducted by Australian researchers at Princess Alexandra Hospital, Mater Hospital, and Queensland Eye Institute, Brisbane, the study reviewed the records of patients who had anterior vitrectomy and scleral-fixated PCIOL implantation between 1993 and 2008 and had a minimum follow-up of 6 months. The researchers looked at 82 eyes of 72 patients (47 men). The mean follow-up was 83.3 months (range 6.7-166.5 months), and the mean age at surgery was 62 years (range 15-97 years). Lead author Andrew S. McAllister, M.B., B.S.(Hons), and Lawrence W. Hirst, F.R.A.C.S., found that visual outcomes were favorable in many cases, with a statistically significant mean improvement in corrected distance visual acuity (CDVA) of 1.6 Snellen chart lines of vision and 59 eyes (72%) with an improved or unchanged CDVA. There were 23 eyes (28%) with a reduced CDVA. However, post-op complications were common, the most common being ocular hypertension (25 eyes [30.5%]). Suture breakage occurred in five eyes (6%) after a mean of 4.9 years; four of these patients were younger than 40 years. Overall, 44 eyes (53.7%) had at least one complica- tion, 36.4% within 1 week post-op and 63.6% after 1 week. Thirteen eyes (15.8%) required at least one further operation. Dr. McAllister said that there was a definite association of suture breakage with young patients, and in those cases, it was most likely due to an active lifestyle with continu- ous microtrauma combined with the biodegradation of the polypropylene sutures and gravitational forces. The complications Michael E. Snyder, M.D., Cincin- nati Eye Institute, said the study was well done, although the complica- tion rate was higher than what he typically sees in his patient popula- tion. Commenting on suture break- age as one of the important compli- cations found in the study, Dr. Snyder said that prolene has been shown to break down with time, which is why he no longer uses it for suturing through the scleral wall. Instead, he uses Gore-Tex sutures as they have no known biodegradation within the time frame required. It's an off-label use but has some significant potential benefits of longevity, especially in the younger patients, Dr. Snyder said. Regarding the risk of endoph- thalmitis, the study suggested it could be reduced by covering the sutures with a scleral flap. However, Dr. Snyder said there is good data from a study with a 10-year follow- up that shows scleral flaps melt away and erode over time in approx- imately 50% of cases. He personally prefers to rotate the knot internal to the scleral wall in almost all in- stances, he said. One tip he learned from Lisa Arbisser, M.D., he said, is not to cauterize in the area of the transcle- ral suture passage and just allow the platelets inside to do their job; the cautery devitalizes the sclera a bit and probably increases the chances of scleral thinning or melting later down the road and the potential for suture erosion. "I'm a bigger fan of sutured posterior chamber implant lenses than anterior chamber implant lenses, and I feel fairly strongly about that. There are a lot of articles that seem to demonstrate relative equivalency, but I think those arti- cles don't always ask the right ques- tions," Dr. Snyder said. A technically demanding procedure The study states that despite the advantages of scleral-fixated PCIOLs in avoiding certain complications, especially in eyes after trauma, the technique is difficult. Dr. Snyder said that when look- ing at the complication rates, part of that is tremendously dependent on the relative skill of the surgeon in doing the particular procedure. There's no more difficult procedure in anterior segment surgery than sutured posterior chamber implant lenses, Dr. Snyder said, and Dr. Hirst's data is good. "He's an extremely experienced surgeon. It's a very difficult thing for those who do not have the same skill set as Dr. Hirst to extend that information to themselves, and cer- tainly I wouldn't advocate someone who does one sutured implant a year to necessarily pick it up." However, Dr. Snyder said the important point in this article is that there can be very safe and successful One study he remembers from 16 or 17 years ago looked at eyes that had gonioscopically proven perfect orientation of the anterior chamber lens footplates; 10 years later, half of the cases had ovaliza- tion of the pupil, he said. "Clearly even a perfectly positioned lens can induce low grade chronic fibrotic changes in the angle," he said. While some may say those issues only occur when the implants are not sized properly or not placed properly, another review seems to negate that, Dr. Snyder said. results with a suture implant, but the technique is so critical and a continually evolving process. Study conclusions Taking into account the complica- tion rate of scleral-fixated PCIOLs, the study authors suggested that open-loop or iris-claw ACIOLs may be the better choice when there are no contraindications for their use. "Compared with scleral-fixated PCIOLs, there is evidence that they provide better visual outcomes, are easier to insert, are comparably safe, and have a much improved post-op- erative course than their predeces- sors," the study said. In addition, the study authors wrote that a meta-analysis of the lit- erature comparing the visual out- comes, complications, and incidence of complications stratified into age and pre-op pathology for scleral-fix- ated PCIOLs and other IOLs would be of great assistance. "The most important message from this study is that as clinicians, we need to keep in mind the indi- vidual challenges, advantages, and complications that can occur with different types of intraocular lenses used to surgically treat aphakia and apply this to patients on a case-by- case basis to provide them with the best long-term visual outcomes," Dr. McAllister said. EW Editors' note: Drs. McAllister and Snyder have no financial interests related to this article. Contact information McAllister: drandrewmcallister@gmail.com Snyder: msnyder@cincinnatieye.com EW CATARACT 27 EyeWorld @EWNews Keep up on the latest in ophthalmology! Follow EyeWorld on Twitter at twitter.com/EWNews