Eyeworld

NOV 2012

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

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26 EW NEWS & OPINION November 2012 Touch and treat function makes lasers more innovative in the retina space by Matt Young EyeWorld Contributing Writer AMD may be out, but lasers for diabetic retinopathy couldn't be more cutting edge U Image of a treatment planned on fluorescein angiography taken with the Navilas system. Spots to treat (small yellow circles) are marked on the angiogram image before treatment. Caution zones are marked as well for safety purposes sing a laser to treat age-related macular degeneration (AMD) has largely been replaced by newer generation therapies like intravitreal injections, but laser innovations still flourish for other retinal disorders. Lasers are reducing treatment time and medications, while raising treatment accuracy for conditions like diabetic retinopathy. Branch retinal vein occlusion (BRVO) and idiopathic perifoveal telangiectasia (IPT) are other conditions that benefit from laser treatment. What's more, the integration between imaging and these lasers is cutting edge. Thanks to Apple (Cupertino, Calif.), touch-screens have become a prominent nat- ural interface between consumers and the digital world. These retinal lasers go a step beyond, translating touch into treatment. Touch. Treat. Simple. "You use it like a smartphone," Alex W. Cohen, M.D., assistant professor of ophthal- mology, Dean McGee Eye Institute, Univer- sity of Oklahoma, Oklahoma City, said of the Pascal Photocoagulator (Topcon Medical Laser Systems, Santa Clara, Calif.). "Pick the pattern you want, the spot size, and do all that on a screen." The bottom-line: AMD and treatments Image of a full retina after a complete panretinal photocoagulation treatment in one single session often bask in the news spotlight because the condition affects a lot of patients, and there's a lot of money involved. But important laser innovations are happening for other retinal conditions that are worth understanding. Navigated retinal photocoagulation The Navilas Laser System (OD-OS, Teltow, Germany) involves a method known as navigated retinal photocoagulation. "Treatment is monitored on a screen," said Igor Kozak, M.D., assistant clinical pro- fessor, Shiley Eye Center, University of Cali- fornia, San Diego, La Jolla, Calif. "We can plan treatment on the images we have ac- quired on the same or other instruments." Other than just being cool by zapping problem areas on a screen, there are concrete benefits to this method. In a study published in Ophthalmology in Once Navilas treatment is planned, the image is overlaid onto the live fundus retina and the laser is activated to treat the marked spots. As seen in this image, planned spots are yellow circles while treated spots become blue Source (all): Igor Kozak, M.D. 2011, Dr. Kozak and colleagues found that Navilas achieved a microaneurysm hit rate of 92% compared to 72% in a control group, meaning that it achieves a higher rate of accuracy in photocoaguation treatments of diabetic retinopathy lesions than a manual laser technique. "There were astonishing differences [in accuracy]," Dr. Kozak said. "Three of ten laser applications using manual laser [often] landed at a spot where we don't want them." By contrast, Navilas indicates the num- ber of lesions left to treat, such that an oph- thalmologist can be confident that the patient receives a complete treatment. The re- treatment rate is reduced, Dr. Kozak said. In case a retreatment is necessary, treatment maps detail where the laser has been applied and at what power. "We can revisit the algorithm and based on what the patient needs, apply higher en- ergy to the same spot or choose a different spot to have a therapeutic effect," Dr. Kozak said. Meanwhile, Dr. Kozak credits eye track- ing for Navilas' accuracy. "A similar concept works for excimer lasers," he said. "Those systems use eye tracking to place the treatment zone on the cornea. Navilas uses a similar concept for retinal procedures." Retinal imaging is more difficult because the retina is less accessible than the cornea— a superficial structure, Dr. Kozak said. Hence, while the Navilas inventors may have had a difficult time, users appear to benefit from the improved accuracy. Typically, diabetic retinopathy patients also receive intravitreal injections—about 7-8 the first year to keep their situation stable, Dr. Kozak said. Navilas can significantly re- duce the number of injections needed subse- quently, he said, although exact data is forthcoming. Dr. Kozak said that many current Navilas patients don't need further injections for a significant period of time. In discussing AMD, Dr. Kozak also be- lieves that lasers may return to play a more important role in the future. "Currently, pharmacotherapy is the best treatment for AMD," Dr. Kozak said. That said, feeder vessels can nurture the choroidal neovascular membrane, he said. Using a navigated system to photocoagulate such feeder vessels and accurately track them could become either an excellent addition to pharmacotherapy or solo treatment. Less time, less pain Dr. Cohen, meanwhile, considers the Pascal Photocoagulator to be "an amazing laser." "I think it has changed the way retinal specialists and general ophthalmologists are able to perform retinal treatment," he said. A surgeon could perform a grid treat- ment with one push of the button, which would never have happened using conven- tional lasers, he said. continued on page 29

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