Eyeworld Supplements

I n a presentation at an EyeWorld CME Education symposium, Eric Donnenfeld, MD, Long Island, N.Y., discussed the future of astigmatic incisional surgery. Today, some surgeons are per- forming limbal relaxing incisions (LRIs), however these incisions include several positives and chal- lenges, according to Dr. Donnenfeld. The pros include that they are inex- pensive, easy to perform, there is minimal instrumentation involved, they can be done at the time of cataract surgery, there is no impact on cataract healing and can be repeated. However, some of the challenges are that they include a variable and unpredictable treat- ment and response. This is because many LRIs performed via hand have imprecise depth, length, angulation, and position of the incision. "LRIs are an art form, not a science," said Dr. Donnenfeld. The response remains unpredictable. This variable response in incision is due to age, corneal diameter/curva- ture, pachymetry, corneal biome- chanics and IOP fluctuations. Femtosecond laser-assisted arcuate incisions are a new alterna- tive to manually performed LRIs. These femtosecond arcuate incisions are fully customizable and ad- justable, now making refractive incisions more of a science instead of an art form. With a femtosecond laser, surgeons are able to place desired incisions at the exact size, place and depth that is intended and planned with sophisticated planning software. Dr. Donnenfeld is currently performing these incisions both with the Catalys (Abbott Medical Optics, AMO, Santa Ana, Calif.) and LenSx Laser (Alcon, Fort Worth, Texas), and also the iFS femtosecond laser (AMO). Dr. Donnenfeld also finds laser arcuate incisions highly adjustable. He is able to titrate response by using the laser to adjust the line separation, spot separation, energy and angulation of incision. Dr. Donnenfeld's nomogram for LRI and arcuate incisions is shown in Figure 1. Dr. Donnenfeld's latest applica- tions of femtosecond arcuate incisions involves the creation of in- trastromal ablations for astigmatism. These incisions are placed by the laser below Bowman's membrane and can be opened partially or fully at the surgeon's discretion postoper- atively, to adjust the level of effect. "The full effect of the incision is not achieved until the incision is manu- ally opened either intraoperatively or postoperatively," he said. Overall these intrastromal incisions are less effective than full thickness incisions, so a smaller optical zone should be used. By keeping Bowman's membrane intact, the patient has less pain, reduced loss of corneal sensation, less dry eye, greater would stability, and no need for antibiotics. In summary, Dr. Donnenfeld believes LRIs and arcuate incisions are now playing an increasingly important role in refractive cataract surgery. Today, most ophthalmolo- gists do not perform astigmatic inci- sions (as discussed in Dr. Vukich's article later in this supplement), and the femtosecond laser may increase the number of doctors performing these procedures. "Femtosecond arcuate incisions may now be made at the time of cataract surgery with increased precision and safety. Additionally, intrastromal arcuate incisions will play an important role in astigma- tism management moving forward," he concluded. Dr. Donnenfeld can be contacted at ericdonnenfeld@gmail.com. by Eric Donnenfeld, MD New levels of precision available for refractive cataract surgeons with femtosecond arcuate incisions " Femtosecond arcuate incisions are fully customizable and adjustable, now making refractive incisions more of a science instead of an art form." Eric Donnenfeld, MD 6 Dr. Donnenfeld provides nomograms for femtosecond arcuates. Femtosecond arcuate incisions provide greater accuracy and precision over manual incisions. May 2014

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