Iris Claw IOLs

[caption id="attachment_5420" align="alignnone" width="750"] José L Güell MD[/caption]     Over 40 years after Prof Jan Worst developed the first iris claw intraocular lens (IOL) for the correction of aphakia following cataract surgery, the concept of an iris-fixated lens has stood the test of time and still offers a safe, efficient and predictable surgical procedure for both phakic and aphakic eyes, according José L Güell MD, PhD, Spain. “Among the advantages are the reversibility, preservation of accommodation in phakic high ammetropic eyes and broad spectrum of ametropic correction. This lens also appears to be a valid option, with a favourable complication rate, for the treatment of aphakic eyes without capsular support,” he told delegates attending his Ridley Medal Lecture at the XXXIV Congress of the ESCRS in Copenhagen, Denmark. Focusing initially on the use of iris-fixated IOLs for aphakia with inadequate capsular support, Dr Güell said that options to surgically correct aphakia include implantation of a transsclerally sutured posterior chamber (PC) IOL, angle-supported anterior chamber (AC) IOL, or an iris-fixated IOL. Angle-supported AC IOLs are rarely used because of the high incidence of secondary glaucoma, pupil distortion, endothelial cell loss, IOL instability and other complications, he said. While transsclerally- or iris-sutured PC IOLs do preserve AC anatomy, and have a relatively low risk of associated complications, when they occur they can be very severe (vitreous haemorrhage, retinal detachment etc.) and are technically challenging to implant. “By contrast, iris-fixated IOLs have been successfully used to correct primary and secondary aphakia in many countries, although they do not yet have FDA approval in the USA. The lenses are easy to implant, deliver favourable visual outcomes and have a relatively low incidence of intraoperative and postoperative complications,” he said. The main advantages of the iris-claw concept include good centration of the lens, reliable fixation for precise astigmatism correction, safe positioning of the IOL in the AC and respect for the anterior segment anatomy. The fact that the phakic lenses are foldable is another advantage, said Dr Güell, with a foldable aphakic model also expected to become commercially available in the near future. Dr Güell noted that the incidence of significant complications appears acceptable with an endothelial cell loss of around 2% per year, which is similar to standard phacoemulsification. While the comparison of results with scleral-fixated IOLs is difficult, most available data favours the Artisan iris-fixated lens because of the surgical time and simplicity, and the severity of the complications. “There is, however, a clear need for more prospective, long-term, multicentre studies for evaluating anterior versus posterior fixation and iris-fixated versus sclera-fixated IOLs,” he said. Turning to discussion of iris-fixated phakic lenses, Dr Güell said that Artisan/Artiflex IOLs can be used to correct a wide range of refractive errors in phakic eyes. “The incorrectly named phakic IOLs are now part of the standard surgical options for the correction of primary and secondary refractive errors,” he said. The iris-fixated phakic IOL includes many of the same advantages as the aphakic lens, said Dr Güell. “Centration and fixation are the main advantages with these IOLs, and compared to other phakic lenses, they have the distinct advantage of preserving the AC anatomy,” he added. Dr Güell also emphasised the importance of patient education in helping to reduce long-term complications. “All of our patients should understand the relevance of periodic postoperative controls throughout their lives, as well as the temporality of the phakic IOL procedure. We need to stress that the anatomy of the eye changes as we get older, so it is critical to monitor the situation on a regular basis to avoid long-term problems with these implants,” he said. Summing up, Dr Güell said that despite implantation difficulties associated with phakic iris-fixated lenses, he believed that most published complications are surgeon-dependent and related to patient selection and surgical technique. “The Artisan/Artiflex group are my favourite phakic IOLs and I think the near future will possibly see an improvement in our current outcomes with the introduction of multifocality and acrylic material with these lenses,” he said. José L Güell: guell@imo.es