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Innovations | Jul/Aug 2013

Why I Chose My Excimer Laser Platform

Surgeons share what sets their device of choice apart from others on the market.

MEL 80

This device can provide superb clinical outcomes, even in the extremes of ametropia, and has optimal solutions for presbyopia and therapeutic repair.

By Dan Z. Reinstein, MD, MA(Cantab), FRCSC, DABO, FRCOphth, FEBO

There are a number of reasons why I chose the MEL 80 (Carl Zeiss Meditec; Figure 1) as my excimer laser platform. These fall into two general categories: technology and applications.

Technology. The MEL 80, a flying spot laser operating at a repetition rate of 250 Hz, represented a quantum leap in excimer laser technology when it was launched in 2002. The focus of its design was to maximize the energy stability and reliability of the laser delivery system. This was achieved in several ways. The efficiency of the laser beam path is optimized by the use of only five mirrors and the fact that 90% of the beam path is through a vacuum tube. The laser system also includes closed-loop energy regulation, resulting in an extremely consistent energy fluence. Another unique feature of the MEL 80 is the patented beam shaper that guarantees the Gaussian beam shape (achieved using a lenslet array much like those used in Hartmann-Shack wavefront sensors), and that does not require beam focusing as a regular maintenance issue. Another patented feature, the cone for controlled atmosphere, ensures that the final part of the beam path— through air to the patient’s eye—is maintained as a consistent environment by plume homogenization, as opposed to straightforward plume extraction.

Finally, the calibration process uses test phase cards with calibrated aluminium foil to test fluence, beam profile, and scanning mirror spot placement accuracy simultaneously. A display of the real-time energy variance demonstrates how tightly fluence is controlled by the MEL 80, and the user is able to change the fluence delivered in 2% steps, resulting in very high-accuracy energy delivery. This 20-second process enables a calibration check to be performed for every patient immediately before treatment, thus optimizing outcomes.

For the user, the product of all these features is a remarkably stable, consistent, and reliable laser. For example, in my practice, the fluence setting value (selected during calibration) was between 0 and 2 (ie, within 4%) for 97% of treatments in the first 4 months of 2013. Additionally, service visits are kept to a minimum; our center has required only five functional service visits and 14 preventive maintenance visits in the past 3.5 years. Most important, we have never, in 10 years of use, had to reschedule patients because of a technical failure with the MEL 80, and the device has provided us with superb clinical outcomes, even in the extremes of ametropia (6.00 D to -12.00 D).1-3

Applications. With respect to applications, the MEL 80 has always included a wavefront-optimized aspheric ablation profile as the standard base profile for myopia, and the hyperopic ablation profile has also been unsurpassed in stability and safety. Wavefront-guided treatments were coupled with wavefront-optimized (aspheric) base profiles from the laser’s inception in 2002, allowing manifest refraction to be combined with higher-order aberrations (HOAs). The Wavefront Supported Custom Ablation (WASCA) aberrometer has been the highestresolution wavefront sensor linked to an excimer laser until recently, as other providers are beginning to provide resolutions in a similar range. The 1,000-Hz eye tracker provides a 4:1 tracking-frame-to-pulse ratio, resulting in an extremely low full-loop delay between 2 and 4 milliseconds. The eye tracker includes a sophisticated cyclotorsion registration system that identifies the pupil, iris, limbus, and conjunctival vessels. It also allows manual centration by direct visualization of the position of the red heliumneon laser aiming beam so that it is simple to center the ablation on the corneal reflex of a coaxially fixating eye.

The applications that stand out for the MEL 80 are Presbyond Laser Blended Vision and the options for therapeutic repair of previous refractive surgery complications. Laser Blended Vision1,2,4 is a solution for presbyopia that meets the goal of good binocular vision at all distances, with no compromise in safety, contrast sensitivity, or night vision and with retention of functional stereoacuity. Since developing the Laser Blended Vision technique in 2003, my practice virtually eliminated the need for clear lens exchange and multifocal IOLs.

In addition to wavefront-guided custom ablation,5 the MEL 80 has a topography-guided custom ablation algorithm,6 which improves on the original 1998 MEL 70 Topography Supported Customized Ablations (TOSCA) topography-guided module. The topography-guided profile with the MEL 80 achieves excellent regularization of the cornea with high refractive accuracy. The MEL 80 also has a versatile phototherapeutic keratectomy (PTK) mode7 that can be used for treating irregular astigmatism by performing transepithelial PTK. Finally, maximum versatility is provided by the spot PTK joystick, which is essentially a 0.7- mm microscalpel enabling extreme localization and control of ablation; this feature can be applied in a wide variety of unusual situations such as flap edge discontinuity after epithelial ingrowth, Salzmann nodules with scarring, anterior basement membrane dystrophy, scarred radial keratotomy incisions, and lattice and other corneal dystrophies.8

Dan Z. Reinstein, MD, MA(Cantab), FRCSC, DABO, FRCOphth, FEBO, practices at the London Vision Clinic, London, and is affiliated with the Department of Ophthalmology, Columbia University Medical College, New York, and the Centre Hospitalier National d’Ophtalmologie, Paris. Professor Reinstein states that he has financial interests with Carl Zeiss Meditec and ArcScan Inc. He may be reached at e-mail: dzr@londonvisionclinic.com.

  1. Reinstein DZ, Couch DG, Archer TJ. LASIK for hyperopic astigmatism and presbyopia using micro-monovision with the Carl Zeiss Meditec MEL80. J Refract Surg. 2009;25:37-58.
  2. Reinstein DZ, Archer TJ, Gobbe M. LASIK for myopic astigmatism and presbyopia using non-linear aspheric micro-monovision with the Carl Zeiss Meditec MEL 80 platform. J Refract Surg. 2011;27:23-37.
  3. Reinstein DZ, Carp GI, Archer TJ, Gobbe M. Transitioning from mechanical microkeratome to femtosecond flap creation: comparing experienced vs novice LASIK surgeon visual outcomes for the first 200 myopic procedures. J Cataract Refract Surg. 2012;38:1788-1795.
  4. Reinstein DZ, Carp GI, Archer TJ, Gobbe M. LASIK for the correction of presbyopia in emmetropic patients using aspheric ablation profiles and a micro-monovision protocol with the Carl Zeiss Meditec MEL80 and VisuMax. J Refract Surg. 2012;28:531-541.
  5. Reinstein DZ, Archer TJ, Couch D, Schroeder E, Wottke M. A new night vision disturbances parameter and contrast sensitivity as indicators of success in wavefront-guided enhancement. J Refract Surg. 2005;21:S535-540.
  6. Reinstein DZ, Archer TJ, Gobbe M. Combined corneal topography and corneal wavefront data in the treatment of corneal irregularity and refractive error in LASIK or PRK using the Carl Zeiss Meditec MEL80 and CRS Master. J Refract Surg. 2009;25:503-515.
  7. Reinstein DZ, Archer TJ, Gobbe M. Refractive and topographic errors in topography-guided ablation produced by epithelial compensation predicted by three-dimensional Artemis very high-frequency digital ultrasound stromal and epithelial thickness mapping. J Refract Surg. 2012;28:657-663.
  8. Reinstein DZ, Archer TJ, Gobbe M. Spot PTK for keratin plugging in radial keratotomy incisions. Available at http://www.youtube.com/watch?v=-H0l_kvHPvc&feature=youtube.

Nidek EC-5000

This excimer laser has a 20-year history of excellent clinical outcomes and satisfied patients and surgeons.

By Alaa El Danasoury, MD, FRCS

We began performing excimer laser surgery at Magrabi Eye Hospitals and Centers as early as 1990 and had one of the first excimer laser systems worldwide. In 1993, we acquired the first-generation Nidek EC-5000 excimer laser (Nidek Co., Ltd.; Figure 2), which was the state-of-the-art excimer laser at the time, with its large ablation zone and flexible transition zone. Since those early years, the platform has undergone signficant change, and it remains at the forefront of excimer laser technology today. For example, the current Navex Quest platform includes aspheric ablation profiles and ocular wavefront-guided, topographyguided, and optimized prolate ablation (OPA) algorithms to treat virtually any refractive surgery candidate based on his or her specific ocular characteristics and needs.

Our group comprises 32 refractive surgeons at 26 centers and strives to be on the cutting edge of excimer technology. Over the years, we have evaluated other excimer lasers to determine the differences between platforms. However, we have never felt the need to change our main platform (Nidek), as it provides all the modern aspects of laser vision correction. The suite of technology in the Nidek excimer platform includes automated cyclotorsion error correction and a 1-kHz eye tracker. The Nidek platform differs from other platforms in three significant facets: (1) preoperative measurement, (2) treatment planning, and (3) surgical treatment.

Preoperative measurement. The first step in successful surgery is accurate preoperative measurements, and the diagnostic tools included in the Nidek excimer laser are outstanding. The OPD Scan III is a combination topographer, aberrometer, pupillometer, autorefractor, and keratometer. It is a valuable tool for pre- and postoperative use in excimer laser and anterior segment surgery, including cataract surgery and phakic IOL implantation. The OPD Scan III includes corneal disease screening software, a useful adjunct to the surgeon’s clinical impression. Comparison of corneal topography and internal aberration maps allows the surgeon to select the most appropriate treatment for each patient. Additionally, the difference in the pupil center (line of sight) and corneal vertex are plotted on all maps to aid ablation centration. Advanced treatment planning software allows us to separate lowerorder aberration (LOA) corrections (sphere and cylinder) from HOA corrections for greater flexibility of treatment. We can choose to correct some or all of the HOAs based on the clinical picture.

Treatment planning. The OPA profile provides an unmatched physiologic prolate shape over the mesopic pupillary area,1 potentially improving postoperative visual quality (Figures 3 and 4).2 For treatment planning with this profile, the surgeon can modify the target spherical aberration and tailor it to presbyopic patients. Currently, we target -0.30 μm spherical aberration in both eyes, which increases depth of focus and improves near vision by approximately 0.75 D; this can be combined with minimonovision (0.75 D of myopia) in the nondominant eye.

Surgical treatment. During treatment, there is automated compensation for cyclotorsion; however, with the Nidek excimer focusing slit beam, as opposed to the focusing spot beam used in many other platforms, the surgeon can detect any head tilt during ablation. This is significantly more effective with slit illumination. During ablation, the laser arm moves to follow the eye’s movements, as opposed to only the laser optics. This leads to more accurate delivery of laser energy to achieve the intended correction.

Operation of the Nidek laser is exceptionally costeffective. We operate in 26 locations in six countries and have a total of 19 Nidek platforms and two other systems. As the director of refractive surgery, I can appreciate the longevity of the Nidek laser cavity and the significantly lower maintenance cost with these systems compared with others. An additional advantage is the lack of a per-click fee with the Nidek EC-5000. The Nidek platform has given us a 20-year history of excellent clinical outcomes, satisfied patients, and consequently satisfied surgeons.

Alaa El Danasoury, MD, FRCS, is Chief of Cornea and Refractive Surgery Service at Magrabi Eye Hospitals and Centers, Saudi Arabia, Gulf Region & Egypt. Dr. El Danasoury did not provide financial disclosure information. He may be reached at e-mail: malaa@magrabi.com.sa.

  1. El Danasoury AM. NIDEK optimized prolate ablation for the treatment of myopia with and without astigmatism. J Refract Surg. 2009;25(Suppl):S136-S141.
  2. El Danasoury AM, Holladay J, Waring GO 3rd, Pieger S, Bains HS. A contralateral, randomized comparison of optimized prolate ablation and conventional LASIK for myopia with the NIDEK excimer laser platform. J Refract Surg. 2012;28(7):453-461.

Schwind Amaris

The laser’s tracking system and centration can track eye movements in six dimensions.

By Paolo Vinciguerra, MD

After more than 25 years’ experience with excimer laser cornea-based refractive surgery, my current laser system is the Schwind Amaris 750S (Schwind eye-tech-solutions; Figure 5). I have chosen this as my excimer laser for a number of reasons, including the responsiveness of the company to feedback, the features offered by this refractive platform, and the excellent clinical results it provides.

I have found that Schwind is a responsive, flexible company that consistently aims to improve this device’s hardware and software. The reaction of Schwind’s research and development team to my feedback is always reliable and precise.

A variety of features distinguish the Schwind Amaris 750S from other refractive laser platforms on the market. The laser’s tracking system and centration can track eye movements in six dimensions. The system determines the visual axis, tracks it, and automatically centers the ablation of LOAs on this axis. By contrast, HOA ablation is centered on the pupil center, from which it has been calculated. This makes a difference in outcomes; postoperative maps show better centration of the refractive ablation, and results are no longer sensitive to the angle kappa (the distance between the pupil center and the visual axis). Additionally, postoperative coma is much lower than with other laser platforms I have used.

The Schwind Amaris 750S features an integrated optical coherence tomography (OCT) device that can measure corneal pachymetry in real time. This provides feedback between the planned and obtained ablation that is especially useful in retreatments and therapeutic ablations (Figures 6 and 7). Perhaps most impressive is the prolate shape of corneas after treatment with this system. Even after a myopic ablation, postoperative corneal maps show a prolate cornea (Figure 8). It can be difficult to determine whether these eyes have been treated or not. At a recent ophthalmic congress, I showed participants side-by-side OCT images of untreated eyes and other patients after treatment with the Schwind Amaris 750S (Figure 9). No one was able to detect which patient had been treated.

Other advantages of the laser include its large optical zone size and its speed. Most cases performed with the Schwind Amaris 750S are completed within 60 seconds from the start of ablation. This platform also enables the surgeon to treat highly irregular corneas with little difficulty.

Paolo Vinciguerra, MD, is the Chairman of the Department of Ophthalmology, Istituto Clinico Humanitas, Milan, Italy. Dr. Vinciguerra is a member of the CRST Europe Editorial Board. He may be reached at e-mail: paolo.vinciguerra@humanitas.it.

Star S4 IR

Wavefront-guided, iris-registered excimer laser delivery provides maximal treatment of HOAs with meticulous placement of the axis of astigmatism.

By Christopher L. Blanton, MD

The purpose of excimer laser surgery for vision correction is to provide each eye with optimal visual acuity. The more precise the laser, the more likely we are to achieve this outcome. How can we determine which platform is most precise? This may vary from surgeon to surgeon, but I prefer to look at US Food and Drug Administration (FDA) results and phase 4 clinical trial outcomes.

In a study published in the Journal of Cataract & Refractive Surgery, Abbott Medical Optics Inc.’s (AMO’s) wavefrontguided platform, the Star S4 IR (Figure 10), provided 94% of eyes with 20/20 or better and 74% of eyes with 20/16 or better UCVA.1 Since the laser gained FDA approval, multiple advances in refractive surgery have occurred, including iris registration and the advent of the femtosecond laser, which have continuously improved the Star S4 IR’s level of precision. Several studies have documented high levels (20/16 or better) of visual acuity with low enhancement rates.2-4

These results have been achieved with the Star S4 IR in a variety of settings including large corporate laser centers, small individual private practices, and the military; in short, they are highly reproducible, and, in my experience, unsurpassed. The combination of wavefront- guided, iris-registered excimer delivery under a femtosecond flap provides maximal treatment of HOAs with meticulous placement of the axis of astigmatism delivered to a consistently dry stromal bed. This is the recipe for precise results.

In addition to iris registration, the Star S4 IR offers variable spot scanning. Variable beam sizes and repetition rates conserve tissue and optimize treatment times. ActiveTrak eye tracking captures all three dimensions of intraoperative eye movements, with no dilation required, and its automatic centering locates and sets the treatment center to the center of the pupil.

The AMO platform is dedicated to the principle of wavefront-guided treatment of refractive errors with a focus on detecting, measuring, and fastidiously treating all aberrations. Using a Fourier-based algorithm, the aberrometer calculates thermally sensitive delivery of excimer laser pulses designed to create a smooth, swift treatment that attempts to eliminate all aberrations. This information drives the excimer laser delivery, eliminating transcription errors and providing compensation of the cyclorotation that occurs when patients go from standing to a supine position.

Last, the Star S4 IR comes with a dedicated team of technicians, engineers, clinical and business development personnel, and medical monitors, all whom are dedicated to helping users optimize clinical results for their patients. Coupled with its aforementioned features and study outcomes, this comprehensive platform stands apart from others on the market.

Christopher L. Blanton, MD, is in private practice at Inland Eye Lasik, in Ontario, California. Dr. Blanton states that he is a consultant for Abbott Medical Optics Inc. He may be reached at e-mail: blanton007@aol.com.

  1. Jabbur NS, Kraff C; for the Visx Wavefront Study Group. Wavefront-guided laser in situ keratomileusis using the WaveScan system for correction of low to moderate myopia with astigmatism: 6-month results in 277 eyes. J Cataract Refract Surg. 2005;31:1493-1501.
  2. Schallhorn SC, Venter JA. One-month outcomes of wavefront-guided LASIK for low to moderate myopia with the Visx Star S4 laser in 32,569 eyes. J Refract Surg. 2009;25:S634-S641.
  3. Tanzer DJ, Brunstetter T, Zeber R, et al. A prospective evaluation of laser in situ keratomileusis in US Naval aviators. J Cataract Refract Surg. 2013. In press.
  4. Blanton CL. Customizing LASIK flaps with 150 kHz femtosecond technology. Paper presented at: the American Society of Cataract & Refractive Surgery Annual Meeting; March 25-29, 2011; San Diego, CA.

Technolas 217P

This reliable platform expands the refractive surgery market to the presbyopic age group.

By Robert Ang, MD

Choosing an excimer laser for one’s practice is an extremely important decision because it is an expensive piece of equipment. It will take many years to recoup this investment, so the practice has to live with the decision for at least 5 years.

I have had a Technolas 217 system (now Bausch + Lomb Technolas) ever since I started in private practice 12 years ago. At that time, wavefront-guided treatment was the hottest topic in refractive surgery, and the Bausch + Lomb Zyoptix system was the best on the market. Many years have passed, and many companies have introduced other lasers with numerous innovations. However, I have stuck with Technolas, and I now use the Technolas 217P (Figure 11) for the reasons detailed below. First, I am happy with the surgical results achieved with this laser. I get spot-on refractive outcomes using the personalized aspheric program (combined wavefront and aspheric treatment). Rarely will I get a refractive surprise of more than 0.75 D, and my enhancement rate over 12 years is less than 1%. Patients are happy because their vision is stable, and our hospital management staff is happy because we do not need to absorb a significant amount of costs doing touch-ups. The second reason I prefer the Technolas 217P is familiarity. I know the system and how to use the laser. I also know and trust the Bausch + Lomb Technolas application specialists, who provide efficient technical service. During the past 12 years, not once was my laser nonfunctional for more than 1 day. I have never had to cancel surgeries, and this has enabled me to provide consistent service to my patients.

Last but most important of all, we upgraded from the Technolas 217z100 to the Technolas 217P because we can perform Supracor, a presbyopic LASIK algorithm that can treat refractive errors and presbyopia in a single procedure. Now we can attract an additional population of patients. Whereas before we could offer only reading glasses for presbyopic patients older than 40 years of age, now, as long as they qualify based on standard LASIK parameters, we can offer them Supracor LASIK.

We are currently conducting a Supracor study in myopic presbyopes, and early results show promising outcomes.* Likewise, our clinical experience indicates that pseudophakic presbyopic and post-LASIK patients who have become presbyopic can undergo Supracor for presbyopia correction. Further, Supracor has increased hospital revenues in two ways. One, presbyopic LASIK treatments have made up for the decreasing census of young LASIK patients and allowed the hospital to charge more for this premium treatment. Two, while marketing Supracor as a presbyopic treatment, we are incidentally attracting patients who have cataracts and choose to undergo cataract surgery with us.

The Technolas 217P has provided me with a reliable excimer laser platform that can provide safe and accurate LASIK treatments, and it has expanded our market to the presbyopic age group. We look forward to using the nextgeneration Technolas 317* excimer laser in the near future.

*Editor’s note: The Supracor procedure for myopic presbyopes and the Technolas 317 laser are pending receipt of the Conformité Européenne (CE) Mark. Supracor for post-LASIK and pseudophakic patients is under clinical evaluation.

Robert Ang, MD, is Senior Consultant at the Asian Eye Institute in the Philippines. Dr. Ang states that he has financial interest in AcuFocus, Inc.; Allergan, Inc.; and Bausch + Lomb Technolas. He may be reached at e-mail: RTAng@asianeyeinstitute.com.

WaveLight Refractive Suite

This laser pursues excellence through a high level of safety, customization, and durability.

By A. John Kanellopoulos, MD

I started performing LASIK in Europe in 1994 with the Summit excimer laser (Summit Technology, Inc.), and I was also one of the first surgeons to perform LASIK in the United States. At the time, I used Bausch + Lomb’s Automated Corneal Shaper microkeratome to create the flap and the Visx Star S3 to perform the ablation; later, I upgraded to the Visx Star S4 (now Abbott Medical Optics Inc.). Through the years, I have used other excimer lasers including the Technolas 217B, 217C, and 217Z and the LadarVision (Alcon). In 2001, I became one of the first surgeons to use the WaveLight 200-Hz Allegretto Wave excimer laser (Alcon). I have since upgraded lasers, first to the 400-Hz Allegretto Wave Eye-Q laser and most recently to the WaveLight EX500 excimer laser in combination with the WaveLight FS200 femtosecond laser (both by Alcon; Figure 12). The prospect of using this customized technology at an early time in the history of refractive surgery was one of the key reasons of relocating my practice from Park Avenue, New York City, to Europe. We have published results with these lasers for myopia, myopic astigmatism, and hyperopia in more than 20 articles and book chapters.1-24

In my experience, WaveLight is the only platform on the market that can offer a multitude of customized excimer laser treatments for patients with myopia, myopic astigmatism, and hyperopia. The main treatment for myopia is the wavefrontoptimized signature treatment for the WaveLight technology; this is basically a myopic ablation that delivers more spots in the periphery of the optical zone to reduce spherical aberration, one of the main factors causing night vision problems in PRK and LASIK patients (Figure 13).

In patients with significant astigmatism or any type of irregularity, I employ topography-guided treatments with the WaveLight platform. WaveLight was the pioneer of topography-guided treatments in 2003, and it is interesting that, even today, this is a foreign language to most other laser platforms. With the WaveLight platform, topography-guided treatment is not just one entity, as four separate topographers and/or Scheimpflug tomographers can be used to supply diagnostic data. We currently use the Oculyzer II, a version of the Pentacam HR (Oculus Optikgeräte GmbH) incorporated into the WaveLight system, to obtain topographic images and perform customized topography-guided treatments in patients with more than 1.50 D of astigmatism and in all hyperopes to address angle kappa, which we use in combination with flash CXL-LASIK Xtra, a technique we introduced in 2007.

Wavefront-guided treatment is also available with the WaveLight platform. Used in conjunction with the Analyzer II diagnostic device, this platform uses the Tscherning principle, a type of analysis that uses visible light and does not extrapolate data from infrared diagnostic beams as Hartmann-Shack wavefront analyzers do. The Tscherning analyzer is difficult to use, and it does not produce reliable wavefront data in 100% of patients; however, the surgeon is able to directly visualize in the human visual spectrum, view raw data on the retina, and have a direct understanding of how these data are used in generating the wavefront. This gives me confidence in using this information to improve eyes with a high degree of primary HOAs and to treat patients with previous excimer laser refractive surgery who have visual problems attributed to wavefront aberrations.

Finally, the WaveLight technology can use a combination of diagnostic data from axial length interferometry, topography, and wavefront analysis that, when combined and analyzed, can produce a ray-tracing customized treatment that takes into account all of the factors mentioned above, the expected tissue interaction, and whether the case will be performed with LASIK or PRK. The published data so far seem promising with this customized technique.

The ability to use all of these custom options to achieve excellent, stable results with few maintenance issues has made us true believers in the WaveLight platform. In addition to using the equipment, our center has adopted a WaveLight philosophy: pursuing excellence through the use of a multitude of diagnostic devices; performing surgery with a high level of safety and customization; and the ability to work overtime and endure hard, everyday clinical use.

A. John Kanellopoulos, MD, is the Director of the LaserVision.gr Eye Institute in Athens, Greece, and is a Clinical Professor of Ophthalmology at New York University School of Medicine. He is also an Associate Chief Medical Editor of CRST Europe. Dr. Kanellopoulos states that he is a consultant to Alcon/WaveLight and Avedro, Inc. He may be reached at tel: +30 21 07 47 27 77; e-mail: ajkmd@mac.com.

  1. Kanellopoulos AJ, Pe LM, Kleiman L. Moria M2 single use microkeratome head in 100 consecutive LASIK procedures. J Refract Surg. 2005;21(5):476-479.
  2. Kanellopoulos AJ. Topography-guided custom retreatments in 27 symptomatic eyes. J Refract Surg. 2005;21(5):S513-S518.
  3. Kanellopoulos AJ, Conway J, Pe LH: Lasik for hyperopia with the WaveLight excimer laser. J Refract Surg. 2006;22(1):43-47.
  4. Kanellopoulos AJ, Pe LH. Wavefront-guided enhancements using the WaveLight excimer laser in symptomatic eyes previously treated with LASIK. J Refract Surg. 2006;22(4):345-349.
  5. Basmak. H, Sahin A, Yildirim N, Papakostas TD, Kanellopoulos AJ. Measurement of angle kappa with synoptophore and Orbscan II in a normal population. J Refract Surg. 2007;23(5):456-460.
  6. Kanellopoulos AJ. Post-LASIK ectasia. Ophthalmology. 2007;114(6):1230.
  7. Alio JL, Rodriguez AE, Mendez MC, Kanellopoulos AJ. Histopathology of epi-LASIK in eyes with virgin corneas and eyes with previously altered corneas. J Cataract Refract Surg. 2007;33(11):1871-1876.
  8. Hafezi F, Kanellopoulos AJ, Wiltfang R, Seiler T. Corneal collagen crosslinking with riboflavin and ultraviolet A to treat induced keratectasia after laser in situ keratomileusis. J Cataract Refract Surg. 2007;33:2035-2040.
  9. Kanellopoulos AJ, Binder PS. Collagen cross-linking (CCL) sequential topography-guided PRK: a temporizing alternative for keratoconus to penetrating keratoplasty. Cornea. 2007;26(7):891-895.
  10. Kanellopoulos AJ. Comparison of sequential vs same-day simultaneous collagen cross-linking and topography-guided PRK for treatment of keratoconus. J Refract Surg. 2009;25(9):S812-S818.
  11. Krueger RP, Kanellopoulos AJ. Stability of simultaneous topography-guided photorefractive keratectomy and riboflavin/ UVA cross-linking for progressive keratoconus: case reports. J Refract Surg. 2010;26(10):S827-S832.
  12. Kanellopoulos AJ, Skouteris V. Secondary ectasia due to forceps injury at childbirth: management with combined topography-guided partial PRK and collagen cross-linking (Athens Protocol) and subsequent phakic IOL implantation. J Refract Surg. 2011;27(9):635-636.
  13. Kanellopoulos AJ, Binder PS. Management of corneal ectasia after LASIK with combined, same-day, topography-guided partial transepithelial PRK and collagen cross-linking: The Athens Protocol. J Refract Surg. 2011;27(5):323-331.
  14. Kanellopoulos AJ. Long term results of a prospective randomized bilateral eye comparison trial of higher fluence, shorter duration ultraviolet A radiation, and riboflavin collagen cross linking for progressive keratoconus. Clin Ophthalmol. 2012;6:97-101.
  15. Kanellopoulos AJ. The management of cornea blindness from severe corneal scarring, with the Athens Protocol (transepithelial topography-guided PRK therapeutic remodelling, combined with same-day, collagen cross linking). Clin Ophthalmol. 2012;6:87-90.
  16. Kanellopoulos AJ. Topography-guided hyperopic and hyperopic astigmatism femtosecond laser-assisted LASIK: long term experience with the 400 Hz eye-Q excimer platform. Clin Ophthalmol. 2012;6:895-901.
  17. Kanellopoulos AJ. Long term safety and efficacy follow-up of prophylactic higher fluence collagen cross-linking in high myopic laser-assisted in situ keratomileusis. Clin Ophthalmol. 2012;6:1125-1130.
  18. Kanellopoulos AJ, Khan J. Topography-guided hyperopic LASIK with and without high irradiance collagen cross-linking: initial comparative clinical findings in a contralateral eye study of 34 consecutive patients.J Refract Surg. 2012;28(Suppl):S837-840.
  19. Kanellopoulos AJ, Asimellis G. Digital analysis in flap parameter accuracy and objective assessment of opaque bubble layer in femtosecond laser assisted LASIK. A novel technique. Clin Ophthalmol. 2013;7:343-351.
  20. Kanellopoulos AJ, Asimellis G. Long term bladeless LASIK outcomes with the FS200 femtosecond and EX500 excimer laser workstation: the refractive suite. Clin Ophthalmol. 2013;7:261-269.
  21. Kanellopoulos AJ, Spadea L. Point/counterpoint: my ideal ablation pattern for combined CXL treatments. Cataract & Refractive Surgery Today Europe. March 2013.
  22. Kanellopoulos AJ, Asimellis G. Three dimensional LASIK flap thickness variability: topographic central, paracentral and peripheral assessment, in flaps created by a mechanical microkeratome (M2) and two different femtosecond lasers (FS60 and FS200). Clin Ophthalmol. 2013;675-683.
  23. Kanellopoulos AJ, Asimellis G. Essential opaque bubble layer elimination with novel LASIK flap settings in the FS200 femtosecond laser. Clin Ophthalmol. 2013;7:765-770.
  24. Kanellopoulos AJ, Asimellis G. FS200 femtosecond laser LASIK flap digital analysis parameter evaluation: comparing two different types of patient interface applanation cones. Clin Ophthalmol. 2013;7:1103-1108.