Eyeworld

JUN 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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Bag-in-the-lens technique goes toric June 2012 EW CATARACT by Enette Ngoei EyeWorld Contributing Editor the closer the toric element is to the cornea, the better the correction. "The more you put it back- wards, the higher the astigmatism will be to get the same effect of cor- rection," she said. The way the BIL lenses are im- A toric bag-in-the-lens implant Source: Marie-Jose Tassignon, M.D., Ph.D. EyeWorld checks in on new developments with the technique that prevents PCO F ollowing the success of the bag-in-the-lens (BIL) tech- nique in preventing poste- rior capsular opacification (PCO) with the BIL IOL, its inventor Marie-Jose Tassignon, M.D., ophthalmology department, Antwerp University Hospital, and faculty of medicine, Antwerp University, Belgium, developed a spherotoric BIL IOL. Clinical results of the lens were published in the Journal of Cataract & Refractive Surgery. According to the study, spherotoric BIL IOL implanta- tion yielded outcomes similar to those with other spherotoric IOLs, even in eyes with ocular comorbid- ity or irregular astigmatism up to 15 degrees. Led by Dr. Tassignon, re- searchers at the Antwerp University Hospital enrolled 52 consecutive eyes of 35 patients with cataract and corneal astigmatism ranging from 0.9-6.19 D. Spherotoric BIL IOLs were implanted. The IOLs were cen- tered based on the patient's pupil- lary entrance using Purkinje reflexes of the surgical microscope light, the authors wrote. The toric power was between 1-8 D. One-third of eyes had an ad- ditional ocular comorbidity (includ- ing amblyopia) that could influence the clinical outcomes; 5.2% had an irregular astigmatism up to 15 de- grees. According to the report, 12 eyes had high myopia (axial length [AL] >26 mm) and five eyes had high hyperopia (AL <21 mm). The mean pre-op corrected distance vi- sual acuity was 0.58±0.25. Post-op, the uncorrected distance visual acuity (UDVA) was 0.5 or better in 92% of eyes, the mean UDVA was 0.85±0.21 D, the mean magnitude of error was 0.05±0.49 D, and the mean angle of error was 0.29±0.89 degrees. Astigmatism correction was success- ful in 82% of eyes, the study said. A natural progression Having already developed a lens that does not have PCO as it is not de- pendent on the healing process of the capsular bag and its final posi- tion in the eye always remains sta- ble, it was obvious that designing a toric model of the lens was the next step, Dr. Tassignon said. The BIL technique does not po- sition the lens within the capsular bag but instead positions the capsu- lar bag within the lens in a groove that surrounds the periphery of the BIL lens optic, she explained. The BIL lens is anteriorly posi- tioned with a one-sided toric ele- ment, Dr. Tassignon said, because planted allows surgeons to make ad- justments in case that is necessary, which may be an important offer- ing, like in the case of marking the cornea, which depends on the posi- tion of the toric element within the eye. At present, marking the cornea is still a bit of an approximation, and if the axis of the toric element is misaligned even 10 degrees, there will be an immediate decrease of the toric effect of 33%, Dr. Tassignon noted. This ability to position the lens in various ways could be useful in alignment, which is also important because the anatomy of the eye is such that the lens is not necessarily aligned with the cornea, she said. When a lens is implanted within the capsular bag, that element will not necessarily be aligned with the corneal structure, and the vertex of the astigmatism may not necessarily be in the same vertex of the cornea, Dr. Tassignon said. The new lens has been intro- duced in Belgium for approval, and initial clinical studies are proving that it works and has good results. The fact that the lens can be easily reoriented even a year post-op in the case of a misalignment makes it ready to go, she said. There are few side effects with this lens as well, Dr. Tassignon said. The most important side effect is the capture of the iris in the immediate post-op period, which may happen, but it can be avoided by following the procedure precisely and by keep- ing the iris closed for the first 3 days post-op, which is not a problem if there are no complications, she said. Inflammatory reactions follow- ing surgery even in babies and chil- dren are very low, she said, because there is no contact with the bioma- terial and the lens epithelial cells of the capsular bag since the capsular bag is completely closed and with- out any contact with the IOL unless at the level of the lens groove, which is minimal compared to the classical implantation method. With the capsular bag intact, you have very clear eyes immedi- ately after surgery even in eyes with uveitis, she said. Other factors to consider While positive results have made the technique appealing, the main bar- rier to entry with the BIL technique is that the lens requires a very accu- rate approach to cataract surgery, Dr. Tassignon said. "Everything has to be sized, the anterior capsulorhexis must be done in a proper way, centered, done in a certain size, and you also have to do a posterior capsulorhexis, which quite a lot of older generation ophthalmologists are a bit reluctant to do," she explained. However, the younger genera- tion of ophthalmologists is quite op- timistic, and there are now several young ophthalmologists in France who have adopted the technique and this lens, she said. Certainly, as with every new technique, there is a learning curve, Dr. Tassignon said. However, she said it is not a difficult technique to learn. Most surgeons who learn the technique at her surgery center are surprised at how quickly it can be done, she said. "They always think that it is a technique that is done here and there. As it is our routine technique, we do up to 10-12 cases in one day, and you can't do it in that rhythm if it is very difficult," she said. Abhay R. Vasavada, F.R.C.S., Iladevi Cataract & IOL Research Center, Raghudeep Eye Clinic, Ahmedabad, India, who has im- planted about 20-30 BIL IOLs with a 2-year follow-up, but is not doing them routinely, said that his results have been excellent. However, he has found the procedure to be tech- nically demanding and has not been able to consistently put the bag in the lens successfully . EW Editors' note: Dr. Tassignon is the developer of the Tassignon lens (Morcher, Stuttgart, Germany) and receives royalties. Dr. Vasavada has no financial interests related to this article. Contact information Tassignon: +32 3 821 33 77, marie-jose.tassignon@uza.be Vasavada: icirc@abhayvasavada.com 31

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