FEMTO-LASIK and BEYOND - Carl Zeiss, Inc.

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18 Ophthalmology WORLD REPORT VisuMax Femtosecond Laser System (Dr Rupal Shah) a) Change in CDVA: Safety b) Achieved correction (MR SEQ) over time c) Refractive outcome (MR SEQ percent within attempted @ 1m and @ 3m) d) pre-op CDVA vs. post-op UDVA – 500 kHz (Only full-correction cases) She then said that “the tissue separation is very simple and you do not need any fancy instruments”. Experience with ReLEx: Dr Shah described ReLEx smile as a preferred procedure to Femto-LASIK for the treatment of myopia and myopic astigmatism. They are also looking at ReLEx flex for investigating the possibility for hyperopia treatment. She shared the results of 860 eligible myopic eyes (427 OD, 433 OS) in 518 female patients and 342 males with a mean age of 25 years. Preoperatively, the mean spherical equivalent was -4.53D with a range of up to -10D and the mean cylinder was -0.67D and ranged up to -4.5D. 1 month postoperatively, the procedure showed impressive predictability. The mean spherical equivalent (827 eyes) was very close to zero and the range was 1.63D to -1.25D. The trend continued at 3, 6 and 12 months. The refractive outcome was particularly encouraging because there were no nomogram adjustments. The treatment of myopic astigmatism was equally impressive. Taking about complications, she said that there was a suction loss in 13 eyes. In 12 of the eyes, the procedure was immediately repeated with excellent post-operative outcome. The only case which was aborted was the 1st eye which suffered from a suction loss. 5 eyes suffered from deep lamellar keratisis postoperatively. These were either related to the use of high energy settings or due to the use of a new type of instrument. There were few cases of lenticule being stuck on the undersurface of the flap and these could be removed without any incident. Besides these, there were 14 cases of visually non-significant haze that responded to stepping up of steroids and a case of stationary epithelial ingrowth at the flap edge. Two of the ReLEx procedures needed a retreatment and in these an excimer laser ablation was done. She showed topography of a patient with - 4.5D and -1.75D cylinder. “The cylinder gets treated very satisfactorily and there is a nice big zone of flattening,” she said. Hyperopic cases: Dr Shah shared the results of the first 38 hyperopic eyes they have done. “We have treated up to 7.5D of spherical equivalent with some amount of cylinder,” she said in introduction. Explaining the outcome at 1 month, she said, “At 1 month, we have results from 30 eyes, again a mean very close to zero (spherical equivalent of 0.15D ± 0.75D), so the predictability of the instrument is not an issue. The visual recovery is still something to be refined on.” She wasn’t really positive for the CDVA. “We are getting some losses in best corrected visual acuity. Of course, this is getting offset by some gains also in best corrected visual acuity. But, today, Hyperopic ReLEx is a work in progress. ” she said. The stability was also not as encouraging as in myopia. Conclusion: Dr Shah concluded that ReLEx is a promising new modality for laser vision correction. Treatment for myopia and myopic astigmatism has been revolutionized and hyperopic trials have already begun. “This is a work in progress and the results are much better than the initial results that we saw with excimer laser,” she said.
June 2012 Supplement 19 ESCRS ReLEx smile Satellite Symposium Vienna, Austria Cataract & Refractive Surgery Today Europe ReLEx Versus Femtosecond LASIK: A Comparison As a new technique for laser vision correction, ReLEx is a single-step, single instrument operation. By Osama Ibrahim, MD ReLEx smile is a minimally invasive approach to laser vision correction. Instead of a corneal flap, which is mandatory for the execution of LASIK, an intrastromal lenticule is created with the femtosecond laser. The size and shape of the lenticule corresponds to the desired refractive correction in the intact cornea, and the incision is subsequently prolonged to the anterior corneal surface with a very small opening incision. ReLEx uses tissue removal instead of tissue ablation (Figure 1); it achieves a high precision of cutting that contributes to the predictability of the procedure. Comparing results: I have been using femtosecond LASIK for 5 years and ReLEx for 2 years now. In this time, we have performed ReLEx flex and ReLEx smile in approximately 200 eyes and 400 eyes, respectively. Similar to LASIK, ReLEx flex is performed with a corneal flap-like access cut; however, the flap created for ReLEx flex is smaller than the LASIK flap (Figure 2). Another difference is that, for ReLEx flex, after the flap is lifted, the lenticule is peeled off of the corneal bed rather than ablated. ReLEx smile is entirely different from LASIK, as there is no longer need to create a corneal flap. Instead, a small incision is made in the cornea and the lenticule is dissected and extracted through the incision. As our experience with ReLEx grew over the course of the clinical study, we were able to titrate the energy levels of the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) as well as its spot distance and size to make the system more case specific. These adjustments have provided us with more repeatable and reproducible study results. Since then, we have also fine-tuned the lenticule geometry, resulting in more accurate astigmatic correction. Comparing ReLEx smile to femtosecond LASIK, ReLEx smile has a slightly steeper learning curve, yet after mastering it, ReLEx smile became a much easier and shorter procedure. It is a single-step, single instrument operation, and therefore there is no need to move the patient between two lasers as there is during femtosecond LASIK. Additionally, laser treatment time (ie, time to create the lenticule) is nearly the same for all levels of myopic correction. For instance, I can treat -10.00D of myopia in the same amount of time it takes me to treat -1.00D of myopia, provided the eyes have the same cap diameter and optical zone. The long-term results after ReLEx smile and LASIK are similar, but visual recovery can take a bit longer after ReLEx smile in some eyes. However, there is less incidence of dry eye after ReLEx smile compared with LASIK. One more important advantage for the use of ReLEx smile is that the incidence of straie and other flap complications have vanished. Surgical advantages: The major advantage of ReLEx smile is that there is no flap cutting involved, which we believe minimizes the induction of spherical aberration. Without the thread of spherical aberration, ReLEx smile patients are more likely to achieve better quality of vision than patients treated with an excimer laser, which is especially true for those with high myopia. We also believe that ReLEx smile offers better biomechanical stability than procedures employing flap creation, going along with less postoperative discomfort and less cases of dry eye. With no flap displacement, even after trauma, ReLEx smile is the best procedure for those who are involved in contact sports. Figure 1. ReLEx uses tissue removal instead of tissue ablation. Unlike excimer-laser-based procedures, ReLEx smile uses a solid-state laser, and therefore there is no need for consumable gases or tight environmental humidity control. The VisuMax is a silent, soft, and gentle laser. It does not produce any smell, there is no vision blackout during the procedure, and the cornea is not forced into a nonphysiological planar shape. Thus, deformation and artifacts can be avoided in the cutting results, as well as unnecessarily high intraocular pressure (IOP). The procedure: The first step for ReLEx smile is to attach a disposable curved contact glass onto the laser aperture
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