Working With a Company to Produce a Perfect Laser

With over 15 years of excimer laser surgery experience, my practice is approximately 85% LASIK and 15% surface ablation. I perform many referred cases with irregular astigmatism or corneal aberrations following previous refractive surgery and high patient demands. My laser should be effective, stable, technologically consistent and permanently updated. It should also be friendly to use and cost-effective. The diagnostic platform must adapt to the excimer laser technology, and most importantly, adequately link the customer and the industry in order to adapt the laser to my needs. I especially appreciate a company that happily accepts my creativity and proposals to further develop the technology.

Good Diagnostic Platforms
I need a global wavefront aberrometer and a corneal topographer with corneal wavefront analysis. I use global wavefront analysis for preoperative screening and also for treating eyes with abnormal levels of higher-order aberrations. In these cases, I usually prefer today's surface ablation techniques.

For irregular corneas, especially those previously operated on with corneal refractive procedures, I prefer corneal wavefront analysis; diagnostic data do not depend on light conditions or on accommodation. Corneal wavefront analysis always offers data on a larger area than the pupil zone, and I can treat those cases considering corneal optical errors rather than elevation errors. For corneal topography and wavefront, I use the Eyetop Topographer (Costruzione Strumenti Oftalmici, Scandicci Firenze, Italy) or the Keratron Scout (Optikon, Rome, Italy). For global analysis, I use the ORK Wavefront Analyzer (Schwind eye-tech-solutions, Kleinostheim, Germany; Wavefront Sciences, Albuquerque, NM). This system has 1,452 sensing points — higher than any other available wavefront system — that analyze the wavefront error up to the 10th-order Zernike polynomial.

Data would be integrated into the custom ablation manager (CAM) (ORK-CAM or Presby-CAM; Schwind eye-tech-solutions). I think that the surgeon should interact with the diagnostic information to perform the most adequate surgery for each patient. The software would integrate corneal wavefront and global ocular wavefront to develop the most adequate diagnostic treatment pattern. I can decide on and perform the best treatment for each patient.
Excimer Laser Technology
The instrument should be user-friendly and comfortable for the surgeon and the assistants, it should have an adequately fast eye tracker and work at a speed that allows me to perform short treatments in high refractive errors or in moderate and high astigmatism. My excimer laser, the Esiris Schwind Technology (Schwind eye-tech-solutions), features 200 Hz with a small paragaussian spot size of 0.8 mm (Figure 1). The laser beam works like a Gaussian light laser distributor, and it has a large working distance (almost 30 cm). The active eye tracking (350 Hz) has a latency time of <6 milliseconds — one of the fastest on the market. The treating capabilities of this technology are global wavefront-guided treatment, corneal wavefront-guided treatment or aspheric profiles.

For primary cases — and if the eye does not suffer from bad vision — I prefer an eye that is not highly aberrated for the prolate aspheric profile of the CAM software. I automatically consider the postoperative Q value by balancing the induction of aspheric aberration (considering the preoperative Q values of each patient). This allows an individualized treatment plan, not inducing aspherical aberrations postoperatively. I achieve a true optical zone of my choice, compensating for the aspherical aberrations that result due to changes in corneal biomechanics and induced by the flap cut, according with the adjustments made in the software. I perform an aspherical treatment, corneal wavefront or ocular wavefront for individual treatment planning. The energy profile and the ablation frequency allow me to perform fast treatments with shallow ablations. With this technology, I treat higher refractive errors than I could with other excimer lasers.

Microkeratome
I work with femtosecond technology (Intralase Corp, Irvine, Calif) and the Carriazo-Pendular Microkeratome (Schwind eye-tech-solutions). It is the only microkeratome operating with a pendular movement that allows flaps to be cut between 110 µm and 170 µm. It is user-friendly; I can choose 360º hinge positions with smooth cut quality. This microkeratome offers large flaps — larger than those offered with femtosecond technology. It has parallel phases just opposite to regular microkeratomes that usually offer a meniscus-shaped flap. In hyperopia, I prefer the pendular movement. For other cases, clinical considerations determine which technology I use.
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Cost-Effectiveness
I prefer the Esiris Scanning Spot Excimer Laser (Schwind eye-tech-solutions) platform because the laser is not activated with a card; retreatments may be performed without increased costs (Figure 2). My decision to treat does not depend on economic or financial conditions, and it creates a balanced financial use of the excimer laser in my practice.

Future Technological Improvements
I would like to have online pachymetry to measure corneal thickness during refractive corneal surgery. This feature provides safety, both for the patient and the surgeon. Another improvement that I would suggest is average recognition for centroid pupil adjustment. This is important for the correction of astigmatism and for global and corneal wavefront treatments. Schwind expects to make both technological improvements available within 2 years.

Interaction with the Company
I enjoy working with the Schwind engineers. With our collaboration, the CAM software has improved, and we have treated many difficult cases of irregular astigmatism using the corneal wavefront-guided treatment. We have also codeveloped the Presby-CAM software, which is based on the principle of balanced multifocal monovision and can be applied for spherocylindrical as well as for corneal or ocular wavefront corrections. This software enables near and far binocular vision with an increase in depth perception and a minimal loss of contrast sensitivity. This Presby-LASIK procedure binocularly balances the aberrations induced and is neutral in binocular conditions for the induction of aspherical aberrations.

Jorge L. Alió, MD, PhD, is professor and chairman of ophthalmology, Miguel Hernandez University, in Alicante, Spain, and medical director of VISSUM Corp, in Spain. He discloses that he has a patent ownership or part ownership in Schwind eye-tech-solutions. Dr. Alió may be reached at jlalio@vissum.com or +34 96 515 00 25.