EyeWorld Asia-Pacific June 2013 Issue

37 EWAP CAtArACt/IOL June 2013 CHEE Soon Phaik, MD Senior Consultant and Head, Cataract Service Singapore National Eye Centre 11 Third Hospital Avenue, Singapore 168751 Tel. no. +65-62277255 Fax no. +65-62277290 chee.soon.phaik@snec.com.sg T oday, ophthalmologists are seeing a need for a secure method of fixing an IOL in the absence of capsular support. It would appear that we are seeing an increasing number of in-the-bag subluxated IOLs. Anterior chamber IOLs are well known to be associated with uveitis, glaucoma and hyphema (UGH syndrome) which develops soon after implantation due to iris chaffing of an ill fitting or malpositioned IOL. Over time, such an IOL may induce pupil ovalization, endothelial cell loss and corneal decompensation. The traditional method of suturing to the sclera is time consuming and carries risk of suture biodegradation and breakage over 7-12 years when using 10-0 prolene. Risks of suture track infection and endophthalmitis are other important considerations. For these reasons, intrascleral fixation of the haptic with or without tissue glue has recently been popularized. This results in an extremely stable IOL and quiet eye, but the procedure is technically challenging. Iris fixation has recently become increasingly practiced, whereby the haptics of a 3-piece posterior chamber IOL are sutured to the iris using permanent sutures. Though technically easier and quicker to do, this procedure faces similar challenges with suture slippage and possible suture breakage over time. Iris clip IOLs are another option whereby these aphakia correcting implants are enclavated onto the iris, either on the anterior or posterior surface. The latter has been favored for its theoretically reduced risk of endothelial cell loss and the simple implantation technique. In this article, the benefits of using the Artisan aphakia IOL are clearly demonstrated. In the pediatric cataract, correcting aphakia in a small eye can be challenging in the absence of capsular support. Performing a demanding, time consuming procedure in a child’s eye can easily induce a severe fibrinous inflammatory postoperative response. Retro-pupillary fixation of an iris clip IOL has been shown to be safe and effective. Theoretically, it would not be too challenging to exchange the IOL should the need arise as the child grows older. Indeed, a toric version is also available. Apart from children, I have used iris clip IOLs in adult cases of megalocornea where using a standard-sized AC or PC IOL may pose problems which result from the loose fit and excessive movement of the IOL. In cases of severe trauma, where the iris is partly damaged and a sclera fixation procedure is best avoided because of an existing filtration or seton surgery, the clip IOL is preferred to the iris-sutured IOL due to its greater stability in a defective iris. Editors’ note: Prof. Chee is a consultant for Technolas Perfect Vision, Bausch+Lomb, and Hoya Medical Singapore Pte. Ltd., but has no financial interests related to her comments. YAO Ke, MD Professor, Eye Center, SecondAffiliated Hospital, College of Medicine, Zhejiang University, China No. 88 Jiefang Road, Hangzhou 310009, Zhejiang Province, China Tel. no. +86-571-87783897 Fax no. +86-571-87783997 xlren@zju.edu.cn A t present, the means to correct aphakic eyes without sufficient capsular bag support include spectacles, contact lenses, transscleral ciliary sulcus suture- fixated posterior chamber IOLs, angle-supported anterior chamber IOLs, and iris-fixated anterior chamber IOLs. Because of image magnification, aberrations and limited vision field, spectacle correction is often not accepted. Although contact lenses provide better visual results than spectacles, they reduce oxygen permeability of the cornea and have a high risk for keratitis. The implantation of ciliary sulcus sutured posterior chamber IOLs is technically more challenging, takes time and causes complications such as choroidal hemorrhage, retinal detachment and intraocular lens tilting, while the extraction of the IOL is also difficult. The history of angle-supported anterior chamber IOL for aphakic patients is almost twenty years long; however, till now there remain concerns about the high incidence of corneal endothelial cell loss leading to pseudophakic bullous keratopathy, secondary glaucoma, and formation of peripheral anterior synechiae, chronic inflammation, pupil distortion, and IOL instability. Recently it has been found that even if the anterior chamber is deep, the corneal endothelium still suffers progressive reduction, possibly associated with chronic inflammation, the pigment granules on the IOL surface, the rotation of the IOL, and secondary glaucoma. The iris-fixated IOL was introduced to the world in the 1980s, and the Artisan Aphakia IOL (Ophtec BV) has a better design than previous products. The iris-fixated Artisan IOL is mainly used for aphakic eyes without adequate capsular support, and possesses the advantages of less corneal endothelial cell loss, deeper anterior chamber depth, without rotation of IOL and less inflammation. However, the pupil wouldn’t be dilated large enough after iris-fixated Artisan IOL implantation, so if vitreoretinal disease occurs in the future, surgeons may need to remove the IOL, which is fortunately easier than with the angle-supported IOL and ciliary sulcus suture-fixated IOLs. Although there is a small increase in sales of iris-fixated Artisan IOL in China from approximately 2,208 pieces in 2010 to 2,982 pieces in 2012, the proportion of iris- fixated Artisan IOL in all IOLs implanted is still small. In our hospital, the proportion was 0.58% of the total 8,500 implanted cases last year. Due to the easier surgical procedure, fewer complications, and more satisfactory surgical effect, I agree with Dr. Roque that the implantation of the iris-fixated Artisan IOL for aphakia without adequate capsule support is more worthy of promotion than either transscleral ciliary sulcus suture-fixated posterior chamber IOLs or angle-supported anterior chamber IOLs, but we also need further studies to observe the complication profile over a longer period of time. Editors’ note: Prof. Yao has no financial interests related to his comments. Views from Asia-Pacific