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TRANSCLERAL suture fixation of a one-piece foldable, acrylic IOL (AcrySof SA60AT, Alcon) placed through a small clear corneal incision is a reasonable technique to consider for IOL implantation in eyes where there is absence of capsular support, reported Hussein Wafapoor MD at the annual meeting of the American Academy of Ophthalmology. The study involved 30 eyes of 30 patients operated on between August 2001, and April 2003, by two surgeons at the University of Mississippi Medical Center and the Veterans Administration Medical Center , Jackson , Mississippi , US . In all eyes, sulcus fixation without suturing was impossible because of lack of zonular support, and none of the patients were able to use a contact lens. The mean age of the patient population was 51 years, although the series included two infants (ages one and two years). Excluding those latter individuals, preoperative visual acuity ranged from 20/25 to hand motion and was 20/40 or better in only eight (29%) eyes. Preoperative diagnoses included surgical aphakia (15 eyes), dislocated/subluxated cataract (10 eyes), dislocated IOL (2 eyes), and opacified posterior chamber IOL (3 eyes). In addition, 18 (60%) eyes in the series had ocular trauma. The preoperative findings included corneal scarring, angle recession and glaucoma, iris defects, hyphaema, vitreous haemorrhage and chorioretinal scarring with macular oedema. The patients developed no major complications during the IOL implantation. However, 26 complications occurred during a follow-up that averaged seven months. They included seven events that the researchers categorised as visually significant. Those complications included glaucoma in three eyes and a single case each of vitreous haemorrhage requiring pars plana vitrectomy, pupillary capture of the IOL, suture-wick endophthalmitis, and cystoid macular oedema (CMO). Howe ver, with the exception of the eye with CMO, all eyes achieved final visual acuity of 20/40 or better, and visual acuity at last follow-up was 20/40 or better in 21 (75%) of the evaluable eyes in the series. Nineteen (67%) eyes achieved at least one line of improvement in visual acuity and 16 (57%) eyes had two or more lines of improvement, reported Dr. Wafapoor. "Transcleral IOL suturing was introduced in the 1980s, and while multiple techniques and IOL models have been used with good results, the vast majority involved use of a 6 mm sclerocorneal incision. Implantation of a foldable IOL through a small clear corneal incision has been reported in a few recent single case reports, and we wished to review the outcomes of that approach in a larger population," said Dr. Wafapoor. "Our study was not meant to be a comparative trial, and clearly scleral suturing of a posterior chamber IOL is not an innocuous procedure. In particular, it is distinguished from other approaches by leaving a non-absorbable scleral suture permanently in place, which raises the possibility for suture-wick endophthalmitis. However, our efficacy and safety outcomes compare favourably with those reported in numerous studies evaluating other methods, and seem especially reasonable considering that 60% of eyes in our series were post-trauma and thus at increased risk to develop glaucoma and retinal complications. Furthermore, we believe our technique offers the advantages of requiring only a small incision and using a one-piece acrylic IOL with a unique haptic design that enables secure suture fixation to the IOL," Dr. Wafapoor explained. Dr Wafapoor's presentation generated heated discussion in the conference hall among anterior segment surgeons. The paper was reviewed by Samuel Masket MD, and it was further discussed by Randall J. Olson MD, who chaired the session, and panel members Kenneth J. Rosenthal MD, and Stephen H. Johnson MD. Overall, they agreed that the study was well done, but considering elements of the technique and complications encountered, they indicated preferences for alternative approaches. Reviewing the safety data, Dr. Masket added five more eyes in which pigmentary deposits were noted on the IOL to the category of "visually significant" complications. "I would be concerned about the pigmentary deposits because iris pigment dispersion from this IOL gives the potential for secondary glaucoma," he said. Dr. Olson also observed that the anterior truncated edge, hydrophobic acrylic material, and non-angulated haptics of the SA60AT predispose the lens to pigment dispersion. "This is an excellent lens for use in the bag, but I don't think the manufacturer would say it is designed for suturing in the sulcus," he said. Dr. Wafapoor acknowledged that the appearance of mild pigment deposits on the IOL surface is a concern, although he noted that pigment dispersion could occur with transscleral sulcus suturing regardless of implant type. "As noted previously in the literature, that phenomenon might arise due to IOL-iris contact when the haptics are sutured anteriorly at the ciliary-sulcus region, and even iris-fixated IOLs have been described as causing pigment dispersion. In fact, pigment dispersion can occur any time there is iris trauma, whether that be from surgery or ocular injury," he said. Other objections of the reviewers related to the surgical technique. Dr. Masket noted that the combined anterior-posterior approach involving performance of a three-port pars plana vitrectomy mandates the expertise of a surgeon with retinal training. In addition, he noted that the placement of scleral flaps at 3- and 9 o'clock carries the potential for bleeding from the posterior ciliary arteries, use of 10-0 polypropylene suture material can lead to late suture hydrolysis, and single arm suture fixation is more commonly associated with knot externalisation and the potential for long term exposure with endophthalmitis and IOL tilt. Dr. Rosenthal further commented that while polypropylene remains intact over time in the majority of eyes, it does degrade in a subset of patients. Therefore, he suggested a need to explore other suture materials and techniques, and noted he has some limited experience using polytetrafluoroethylene (GoreTex) sutures. "We need to be exploring other suture options, especially in cases involving paediatric and young adult patients where longevity is important. GoreTex is a little large for intraocular use, and that probably accounts for its failure to achieve more widespread popularity. However, it has tremendous tensile strength, does not biodegrade, and so far I have found it to be a good, durable alternative. However, it remains to be seen if it is the suture of choice," he said. Reviewing other options for IOL implantation in eyes lacking capsular support, Dr. Johnson indicated he would favour use of McCanell iris suture fixation or even placement of an anterior chamber IOL as easier alternatives to the technique described by Dr. Wafapoor and colleagues. Dr. Masket also suggested use of McCanell iris suture fixation."That technique may be used in eyes where there is a malpositioned IOL or aphakia, can be used with a foldable IOL, does not require scleral surgery unless vitrectomy is necessary, spares the conjunctiva to allow for future glaucoma surgery, and also involves a shorter surgical time," Dr. Masket said. Dr. Wafapoor responded by citing a recent report from the Anterior Segment Panel of the AAO reviewing papers on IOL implantation in the absence of capsular support [Wagoner MD et al. Ophthalmology 2003;110:840-59]. In their final evaluation, the panel considered 43 articles reporting safety and efficacy outcomes and concluded that the literature supports the safe and effective use of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber IOLs in cases where placement of a posterior chamber lens in the capsular bag or ciliary sulcus is not possible. "The authors further stated there is insufficient evidence to demonstrate the superiority of one lens type or fixation site and that a large, prospective, randomised clinical trial would be needed for precise determination of small differences in visual outcome or complication rates," Dr. Wafapoor observed. Hussein Wafapoor MD
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