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A NEW IOL implanted using an innovative "bag-in-the-lens" technique holds the promise of greatly reducing or even eliminating problems of posterior capsule opacification (PCO) associated with cataract surgery, according to Marie-José Tassignon MD PhD."I think the results really speak for themselves. I have now implanted about 50 patients with this IOL using the bag-in-the-lens technique and I have encountered no incidence of PCO whatsoever," Dr Tassignon told the XXI Congress of the ESCRS. Dr Tassignon, head of the department of ophthalmology at University Hospital Antwerp, Belgium, said that 40 eyes implanted with the new IOL, including seven paediatric cases have had a follow-up of six months to three years. None of these eyes, including the paediatric cases (ages ranged between seven months and four years) presented with posterior capsule opacification within the 5.0 mm optic area. Nor was there any decentration or tilting of the IOL during the follow-up period. Contrast sensitivity remains unchanged with time provided the retina does not present any age-related or other alterations. Postoperative accommodation measured with the RAF ruler ranged between 1.5 D and 2.0 D, suggesting that reading was possible without additional correction to a certain degree. Two eyes presented an iris capture postoperatively, which could be reduced easily. No other complications were observed.Dr Tassignon said that while there was undoubtedly a steep learning curve for surgeons wishing to master bag-in-the-lens implantation, the payback was ultimately being able to offer cataract patients good visual acuity without the attendant risk of PCO.
"Although it is more demanding for the surgeon, the bag-in-the-lens implantation technique offers the advantage of guaranteeing a clear optical axis and a certain degree of accommodation," she said.She added that clinical workshops would be organised in the near future in order to help surgeons to learn the necessary techniques to perform matched anterior and posterior capsulorhexis, which is central to the process. Explaining the principles behind the technique, Dr Tassignon said that she uses a 3.4 mm incision when implanting the lens. The lens is made of hydrophilic acrylic material with a 5.0 mm optic. The lens incorporates haptics with an elliptical shape. The anterior and posterior flanges are perpendicular oriented to each other in order to avoid tilting of the lens. A continuous groove runs between the posterior and anterior haptics. Because of the design of this lens, the patient does not complain of edge effect at night.The lens is currently presented unfolded and needs to be folded manually. The most important part of the implantation procedure is to perform matched anterior and posterior capsulorhexis, said Dr Tassignon. "The novelty of this technique is that both the anterior and the posterior capsule are inserted into a groove located at the periphery of the lens optic after having performed an anterior and posterior capsulorhexis of the same size. The idea is to create a ‘no space no cell' condition where lens epithelial cells cannot proliferate and posterior capsule opacification can be avoided," she said. Because the eye capsule is flexible, it allows bending of the rim formed by the two sides of the capsule to be introduced into the lens' circumferential groove. "Gentle pushing with a blunt instrument is sufficient to locate the lens in place. No vitrectomy is necessary, and the centring procedure is manual", added Dr Tassignon. The accommodative power of the lens is derived partly by the forward movement of the IOL, as pressure is exerted from contraction of the ciliary body, new models are under development in order to obtain easily 4D of accommodation without induction of edge effects due to the transition zones. Further research is planned in order to explain why the Soemmering's ring remains clear and transparent even after three years of follow-up. Marie-José Tassignon, MD, PhD, FEBO |
