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The precision of the femtosecond laser makes it an ideal choice for creating the capsulotomy and for lens fragmentation T he advent of femtosecond laser-assisted refractive cataract surgery has turned a surgery with typically stellar outcomes into one with potentially phenomenal out- comes. While we've seen incremen- tal improvements in intraocular lens technologies over the recent years, it wasn't until the femtosecond laser's applications for cataract surgery started to be explored that we real- ized what opportunity there was to simplify our techniques while (po- tentially) improving safety and enhancing outcomes. Patients undergoing modern cataract surgery are no longer im- pressed with excellent results—they are demanding perfection. Using the femtosecond laser to create the cap- sulotomy and to perform lens frag- mentation can help turn difficult cataract surgeries into simpler ones and can make even routine surgeries easier. That's not to say these devices are not without potential drawbacks. Surgeons using these lasers will have to justify the cost of acquisition and during the early implementation may have to factor in additional time for the surgery until they develop a system that works for their practice. It is my belief, however, that the potential advantages far outweigh any drawback. Laser capsulotomy As refractive surgeons can attest, lasers offer a precision that manual procedures cannot. This extends to the capsulotomy creation during cataract surgery, too. As with corneal laser vision correction, the capsulo- tomy is best centered over the visual axis, and achieving this accurate centration is a challenge with man- ual rhexis techniques. Warren Hill, MD, has shown in several studies that a consistently round and cen- tered capsulotomy helps the implant remain in a more stable position. 1,2 Manual capsulorhexis will never match the precision of a laser. Al- though it's possible to be good at making the capsulorhexis, variability in anterior segment anatomy and pathology among patients makes it impossible to achieve a similar preci- sion to that of the laser. In particular, dense hyperma- ture cataracts, eyes with zonular weakness, or hyperopic eyes with small, shallow chambers pose unique challenges when creating a manual capsulorhexis that simply no longer exist when a femtosecond laser is used. For surgeons who use premium IOLs, a capsulorhexis that is too large or imperfectly circular can create issues with lens centra- tion and stability. That can lead to the need for premium lens reposi- tioning or explantation to alleviate any visual distortion. In my hands, the femtosecond laser is able to create a capsulotomy that will sym- metrically overlap the lens' edge, en- hancing the effective lens position in nearly all cases. Lens disassembly In my opinion, an advantage of femto-fragmentation of the lens nucleus is that it's simply easier to disassemble the lens for emulsifica- tion, especially in denser cataracts or complex situations where excessive manipulation may jeopardize our outcomes (such as zonular dehis- cence, pseudoexfoliative glaucoma, posterior polar cataracts, etc.). The LENSAR laser system (LENSAR, Winter Park, Fla.) data on lens fragmentation shows less cumulative dispersed energy (CDE) with the laser compared to conventional pha- coemulsification. 3 Less CDE, in turn, results in less endothelial cell loss. Similar data suggest that reductions in CDE of up to 95% or more may be possible with grades 1 or 2 nuclear cataracts, such that only aspiration may be needed. With denser nuclei, CDE can be reduced by two-thirds in grade 3 nuclear sclerosis and by 27% in grades 4 or higher. Furthermore, the lens frag- mentation can be performed on any programmed algorithm; some clini- cians have advocated a "pie-shaped" fragment in cases of hard nuclei and a spherical-based fragment for softer cases. There has also been a trend toward faster visual recovery after femtosecond laser in cataract surgery compared to standard phaco. 4 References 1. Hill WE. The importance of the capsu- lorhexis—does it really matter? Presented for LENSAR at: the Annual Meeting of the American Academy of Ophthalmology; October 16, 2010 :Chicago. 2. Hill WE. The component parts of IOL power calculations. Paper presented at: the 25th Asia-Pacific Academy of Ophthalmology and the 15th Congress of the Chinese Ophthalmo- logical Society; September 19, 2010: Beijing. 3. Fishkind W, Naranjo-Tackman R, Villar-Kuri J. Alternative fragmentation patterns in femtosecond laser cataract surgery. Paper presented at: the ASCRS Symposium on Cataract, IOL and Refractive Surgery; April 12, 2010: Boston. 4. Edwards KH, Frey RW, Naranjo-Tackman R, et al. Clinical outcomes following laser cataract surgery. Invest Ophthalmol Vis Sci. 2010;51:5394. Dr. Krueger is professor of ophthalmology and medical director, Department of Refractive Surgery, Cleveland Clinic Cole Eye Institute, Ohio. He can be contacted at 216-444-8518. 11 by Ronald Krueger, MD Lenticular applications of the femtosecond laser in cataract surgery " [There is] less cumulative dispersed energy with the femtosecond laser compared to conventional phacoemulsifica- tion, [which] results in less endothelial cell loss. " Ronald Krueger, MD EW San Francisco " Manual capsulorhexis will never match the precision of a laser. " Update on the latest in refractive cataract techniques and technologies AMO Saturday supplement_SF2013-dl.qxp_Layout 1 4/19/13 11:27 PM Page 11

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