SEP 05, 2012
This small study in the March issue of the British Journal of Ophthalmology reports on the use of Artisan iris-claw lenses in children with aphakia following lensectomy for ectopia lentis. The authors followed the study's five subjects (eight eyes) for a mean of 28 months after implantation with the lenses and conclude that they are safe and effective in this population, with low endothelial cell losses and no postoperative complications. Good spectacle-free distance vision was achieved in 75 percent of eyes.
Mean preoperative logMAR best-corrected visual acuity was 0.21 ± 0.2, compared with mean postoperative logMAR uncorrected visual acuity of 0.04 ± 0.09 (P = 0.04). Mean endothelial cell count was 3312 ± 277 cells preoperatively, compared with 2913 ±268 cells postoperatively, representing a mean loss of 14.2 percent (P < 0.001). Mean defocus equivalent was 11.38 ± 1.04 preoperatively and 2.34 ±0.66 postoperatively.
Data on the use of these lenses in children are limited to case reports and interventional case series. The majority of patients in this study had ectopia lentis secondary to Marfan's syndrome. For these cases, the authors used a staged approach involving early removal of the dislocated lens by pars plana lensectomy and correction of aphakia with spectacles or contact lenses. This was followed later, usually when the child was a teenager and refractive error had stabilized, by insertion of an Artisan iris-claw implant.
The authors say that a significant advantage of these lenses, particularly in patients with Marfan's syndrome, who are at higher risk of retinal detachment, is that no manipulation of the posterior segment or vitreous is required. They note that this contrasts favorably with the drawbacks associated with scleral-fixated posterior chamber implants.
The authors' biggest concern regarding iris-claw lenses in children is how much endothelial damage is incurred initially during insertion and over the long term during the patient's lifetime. They say that the endothelial cell loss rate observed in this study is comparable with the results of multicenter studies of the Artiflex phakic IOL in adults, which report endothelial loss of between 1.5 percent and 10 percent at three years.
Additionally, in the current study, most endothelial losses seemed to appear during surgery and the initial postoperative period and are comparable to reported rates after pediatric cataract surgery, they say. The authors believe that when one considers the alternatives, the overall risk-benefit ratio of iris-claw lens implantation in the current study's population is acceptable. However, long-term data on the effect of these lenses in both children and adults are needed.