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AAO 2002: a walk around the exhibit hall
Companies old and new had lasers and diagnostic devices on display for refractive surgery and more.
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ORLANDO, Fla. — As always, there was a lot of news from the ophthalmic laser industry here at this year’s American Academy of Ophthalmology meeting. I have been reporting about developments in the industry for Ocular Surgery News for more than 10 years now, and once again this year I spent 3 days walking the exhibit floor to learn about updates and new laser products for corrective refractive surgery, new lasers for treating ophthalmic diseases and other items of interest.
There is always a combination of new information on older ophthalmic laser products and new products introduced for me to bring to your attention, and this meeting was no exception. This report includes updates on refractive lasers, diagnostic systems and other ophthalmic lasers.
REFRACTIVE LASER SYSTEMS
All the established refractive laser companies — Alcon, Bausch & Lomb, Carl Zeiss Meditec, LaserSight, Nidek, Schwind, Visx and WaveLight (represented in its own booth, as well as its marketing partner Lumenis’ booth) were in attendance.
Several companies introduced new or upgraded lasers at this year’s meeting, including a concept for the future from WaveLight. In addition to the familiar names above, two new solid-state refractive lasers were introduced at the meeting: the CustomVis Pulzar solid-state Custom Laser Corneal Reshaping System and the LaserSoft diode-pumped solid-state laser from Katana Technologies GmbH.
The new and upgraded lasers are described below.
WaveLight
This company, which is in the final stages of preparing its submission to the Food and Drug Administration for treatment of myopia with and without astigmatism with its Allegretto laser, unveiled what it called a “concept” for the future of refractive lasers.
The features of the new “concept” laser included a 500-Hz repetition rate, which would cut the ablation rate down to 2 seconds per diopter, bringing the treatment time for a –3 D myopic correction down to 6 seconds and a –6 D correction down to 12 seconds — about one-fourth the time for its current 200-Hz Allegretto. The system would have a matching 500-Hz tracker with a delay time of as little as 2 ms to 3 ms. In addition, its wavefront diagnostic system would have built-in intraoperative adaptive optics that would allow users to screen appropriate corrections prior to performing them. The laser system would also have built-in optical pachymetry to measure 1-µm changes on the corneal surface while the ablation is being performed.
Of course, as the company emphatically stated, these improvements are for now only conceptual in nature, but they might become a reality some time in the future.
Visx
The Star S4 laser, which was introduced at the AAO meeting, is fully customized-ablation-ready, with upgraded algorithms and the capability of producing the PreVue lenses that allow patients to see what custom solutions to their vision might be like before deciding to go ahead with the actual procedure. The S4 system combines the laser and the WaveScan diagnostic system. It is now available for performing conventional ablations and will require only a new keycard to perform custom ablations as soon as the company’s custom ablation approval is received. Company representatives said approval is anticipated sometime during the first half of 2003.
As for future improvements in the Visx platform, Liz Davila, the company’s chief executive officer, in her presentation at the Catch the Wave symposium sponsored jointly by the International Society of Refractive Surgery and the AAO’s Refractive Surgery Interest Group, talked about some of the changes she anticipated. The company is working on cyclotorsion eye tracking, which uses iris pattern information for automatic axial registration of the diagnostic and treatment data. This should be available within a year. Multifocal ablation patterns for correcting presbyopia are in clinical trials, both in the United States and internationally. Adaptive optics built into the WaveScan device for pre-screening custom corrections before they are done — thus avoiding the need for the PreVue lens – are under development. And combinations of wavefront with both topography and ray tracing are in development.
Carl Zeiss Meditec
Meditec introduced its new upgraded refractive laser system, the MEL 80. As shown in the accompanying table comparing the major refractive laser systems, the new MEL 80 is a small-spot, fast-pulsing scanning laser system, with a matching fast-response active eye tracker with automated pupil capture. The laser is mounted on wheels and can be easily moved from room to room or out of the way in the surgery suite, with a rapid, easy, reset time.
The MEL 80 replaces the MEL 70 G-Scan. The laser employs an algorithm to produce aspheric/prolate corneas (remember: prolate is better than oblate) to help reduce induced higher order aberrations, especially spherical aberration.
The laser is used with the WASCA wavefront aberrometer, based on the WaveFront Sciences COAS system (see below). It showed excellent results in a LASIK nomogram validation study performed by three European ophthalmologists in Belgium, Poland and the Czech Republic. One of the surgeons, Frank Goes, MD, showed that higher-order aberrations up to fourth order did not increase significantly with the laser. Together the surgeons treated 174 eyes. In the cumulative results, 84% of eyes achieved 20/20 or better and 7% were 20/15 after 1 month. Ninety-three percent were within ±0.5 D in accuracy of predicted outcome.
The laser system links to workstations for producing wavefront (WASCA) and/or topographic (TOSCA) diagnostics, or to the new CRS Master, which combines the outputs of both topography and wavefront in a single device. The latter, still undergoing proof of concept, is expected to be released for sale sometime in 2003.
Nidek
Even though this company is under legal attack in the United States, it unveiled its latest concept for customized ablation, the NAVEX system, at the meeting.
(Nidek just lost a jury trial over patent infringement to Summit Technology, now owned by Alcon, and is about to go to battle over patents with Visx next spring.)
NAVEX consists of the new EC-5000 CX II NAVScan laser system, the NAVFocus eye tracker, the NAVWave OPD-Scan that combines wavefront analysis with corneal topography to map aberrations of the entire optical system, and the NAVTome MK-2000 microkeratome. The EC-5000CX II, which was officially introduced at this meeting, includes an improved, faster sampling and response four-beam infrared eyetracker with automatic pupil registration of the undilated eye and a new cyclotorsion error-correction algorithm, along with the multispot ablation system (MultiPoint) announced at last year’s AAO meeting.
Another word about Nidek’s legal problems: During the AAO meeting, a Nidek representative provided me with a copy of an appeal filed with the court asking the judge to overturn the jury verdict that awarded Summit/Alcon $14.8 million in damages in the Summit vs. Nidek trial. In this appeal (actually titled a “Memorandum of Law in Support of Defendent’s Renewed Motion for Judgement as a Matter of Law”) Nidek’s attorneys claim that Summit’s expert infringement technical witness, Dr. Michael Feld of MIT, admitted that Nidek’s laser did not infringe key claims of either the Summit Azema or Marshall patents during cross-examination. From this document, it seems in my opinion that Nidek may have a strong case for overturning the verdict. The judge’s ruling is expected by year’s end. It should be made clear that the outcome of the trial affects only the company and not its customers and equipment users.
CustomVis
The new CustomVis Custom Laser Corneal Reshaping System is composed of the Pulzar small spot (0.6 mm), fast pulse (300-400 kHz) CrystalScan solid-state spot scanning, 213-nm quintupled YAG solid-state laser, combined with a three-facet solid-state tracking system. The tracking system includes the analog-based Ztrak limbus-based system, operating at 5 kHz; a video-based tracker for proper registration that locks onto the limbus of the eye; and a digital tracking system that monitors and adjusts for both eye movement and gaze direction.
These systems are totally integrated and have a closed-loop 1 kHz response time. The diagnostic system uses an Orbscan topography device for measuring surface abnormalities, and will, in the future, possibly use the Tracey VFA (visual function analyzer) wavefront diagnostic system for higher order aberrations. A laser epithelial keratomileusis (LASEK) surgery approach is recommended to minimize flap aberrations.
By properly registering the wavefront and topography data, along with minimizing the problems of centration and cyclorotation and intraoperative eye and gaze tracking, along with using LASEK to avoid flap problems, company officials say they hope to minimize all potential problems and deliver superior results for custom surgery.
Katana Technologies
Katana is a new German company that has developed a diode-pumped, frequency-shifted, solid-state laser, operating at 210 nm. The LaserSoft system has a tiny 0.2-mm to 0.3-mm near gaussian spot that pulses at about 1 kHz with a fluence of 120-200 mJ/cm2, delivered under computer-controlled scanning. The active eye tracker is continuous, with a latency of 1 ms. The solid-state laser platform, based on patented technologies, allows the future introduction of a dual system, wherein two lasers could be combined in one unit, combining the ultraviolet refractive wavelength with an infrared laser microkeratome. The latter is now under investigation.
As far as we were able to determine, the company has no plans to enter the U.S. market at this time.
DIAGNOSTICS
There was not much new on the diagnostic front, except for the feeling that all of the wavefront devices had been further tested and refined since last year. There is still a need for standardization of the many wavefront devices, so that results can be used across platforms. As it stands now, results for each device appear repeatable for an individual’s eye, but those results are not repeatable across platforms.
A few new developments that were announced are reported below.
WaveFront Sciences
The company is selling its Complete Ophthalmic Analysis System (COAS) wavefront analyzer as a stand-alone unit for $50,000. It is also installed on Carl Zeiss Meditec’s MEL 70 G-Scan — or the new MEL 80 — laser systems as the WASCA outside of the United States. The WASCA/COAS system was first introduced to the ophthalmic community at the 2000 American Society of Cataract and Refractive Surgery meeting.
The company also introduced its new high-definition COAS-HD wavefront analyzer with, as the company put it, “a new record-setting level of sensor resolution, providing a detailed view of the human eye that has never been seen before.”
Dan Z. Reinstein, MD, explained the importance of “resolution” in achieving accurate and reproducible wavefront measurements for custom ablation treatments. In a presentation at the Catch the Wave symposium, Dr. Reinstein showed a table, reproduced here, that compared the resolution offered by the wavefront devices in use today for customized ablation. As shown in the chart, the current WASCA/COAS system has twice the resolution of the next nearest device, while the new COAS-HD offers four times the resolution, with 3,300 lenslets within a 7-mm pupil.
According to the company, the extremely high resolution of the COAS-HD exceeds what can be adequately described by the mathematics of the Zernike polynomials. So, in addition to a regular Zernike deconstruction, the COAS software now includes a zonal reconstructor that reveals features as small as 0.1 mm in the wavefront map. This extremely fine resolution has the potential to reveal the causes of night glare and halos that occur in some post-LASIK cases, according to the company. The zonal map has also been included in the software for the regular COAS device, along with point-spread function, modulation transfer function and a power map.
Tracey Technologies
With this company’s purchase of the EyeSys topographer last July, Tracey is now working to combine the EyeSys with its VFA ray tracing unit to provide a combined readout of both topographic corneal surface and wavefront abnormalities. Clinical studies are under way in London with Julian Stevens, FRCOphth, and will soon be in the United States with Stephen Slade, MD. The system will employ eye modeling to provide image simulation, including simulated night vision for a dilated eye, according to the company.
Haag-Streit
This company, along with Carl Zeiss Humphrey and others, is working on the development of noncontact online pachymetry, to be used in conjunction with refractive surgery to show changes in corneal thickness as ablation occurs. In a demonstration of the HS Pachymeter at the company’s booth, a decrease in corneal thickness was shown as a flap was created and moved aside, and a further change in corneal thickness could be observed as laser ablation proceeded. The device is also useful for showing the distance of the laser from the eye’s surface. Haag-Streit has a prototype device in development and is working closely with companies such as Schwind, WaveLight and Bausch & Lomb.
One potential problem that I observed was that only a single point of light is projected onto the central cornea. Thus no information is provided about what is happening off-center. Perhaps a multi-point light source and pickup will be developed in the future.
In conversations with me, company officials contended that single-point measurement in the corneal center is most important for determining flap thickness for both myopic and hyperopic corrections, while for intraoperative myopic corrections (typically 85% to 90% of total procedures) the central point is by far the most important because the central cornea is in general the thinnest part of the cornea and the ablation depth is deepest in the center. They also pointed out two significant disadvantages inherent in multipoint or peripheral measurements: multipoint pachymetry results in an increased measurement time; and compared to a single point measurement, multipoint measurements lead to a decrease in accuracy due to motion artifacts resulting from the longer measurement acquisition time.
I agree with their arguments, but I still think that a real-time multipoint measurement might some day be possible, in the same way that ray-tracing aberrometers provide rapid multiple measurements of the internal aberrations of the eye.
In an interesting development, Haag-Streit was pleased to learn that their pachymetry device may have interest for glaucoma specialists as well as refractive surgeons. The Ocular Hypertension Treatment Study, a large, long-term study, found that corneal thickness has an effect on tonometry measurements. Many factors — race, age, time of day of measuring and others — can be combined to create formulae that could be used to adjust tonometry readings and thereby avoid false diagnosis and the prescription of unnecessary medications.
The new Haag-Streit technology attracted interest from glaucoma surgeons at the meeting because of its accuracy, its noncontact administration (ie, it can be used by screeners who are not qualified medically to administer drops or touch the cornea) and its “Tonofit” program, which can adjust tonometry readings according to corneal thickness, with the possibility for the user to change the formula by which this adjustment is made.
Corneal Science
Dr. Alan Touch, an old friend from my contact lens days, is now the chief executive officer and chief technology officer of a company called Corneal Science, which is involved in dry eye and tear research. He told me that his company has a solution to the problem of dry eye after LASIK. Corneal Science produces a tear profile testing system that can screen for certain proteins in the tear film that may indicate which patients are predisposed to develop dry eye following LASIK.
The Corneal Science Tear MicroAssay System measures for the tear protein lactoferrin (LFN), immunoglobulin E (IgE) and other tear film components. Low LFN levels are an indicator of tear-deficient dry eye, Dr. Touch said. If low levels are detected in a screening during an eye exam for LASIK, this could prevent the patient from undergoing LASIK and subsequently developing dry eyes. On the other hand, very high LFN levels are indicative of evaporative dry eye, and these patients also have a risk of poor outcomes.
Many patients interested in LASIK are asymptomatic but have a history of dry eye somewhere in their past, either as contact lens failures or for other reasons. Both problems can be treated before surgery to increase the chance of a favorable outcome.
Recent studies have indicated that patients with normal LFN levels are more likely to have favorable LASIK outcomes, while those testing with low levels demonstrated a threefold increased risk for off-target outcomes. These results indicate that corneal healing and LASIK outcomes are related to LFN concentration levels.
OTHER OPHTHALMIC LASERS
Many new ophthalmic lasers were introduced at this year’s AAO meeting — several new photocoagulators, diode lasers for treating age-related macular degeneration (AMD), and even combination laser systems for treating more than one part of the eye. There was a plethora of “green” laser photocoagulators on the floor. I counted 10 different systems, with one more to come — the green laser built by Iridex but to be sold by Bausch & Lomb as the Millennium EndoLase, part of its Millennium phacoemulsification system. This laser awaits 510(k) FDA clearance before being marketed. The ten systems shown on the floor are listed in the accompanying table, and the newer ones are described within the company writeups below.
biolitec
In addition to its Ceralas G2 diode-pumped doubled YAG tabletop laser, biolitec had its Ceralas M 689-nm diode laser for photodynamic therapy (PDT) on display. This laser, for the treatment of wet AMD via activation of verteporfin, is for sale only internationally, as it is not yet cleared for use in the United States.
Iridex
Iridex introduced its new Iris Medical OcuLight Symphony laser system at the meeting. It combines two of Iridex’s standby lasers in one package with one delivery system, the GLx green laser and SLx infrared diode laser, which has two spot sizes for retinal photocoagulation or performing transpupillary thermotherapy (TTT).
According to the company, the OcuLight Symphony is the first laser system to combine the clinical versatility and convenience of 532 nm, 810 nm and large-spot 810 nm into one laser delivery device. This advanced, top-of-the-line system provides solid-state reliability in an integrated package indicated for retinal photocoagulation and glaucoma procedures. In addition to the two laser consoles, the OcuLight Symphony consists of a multifiber slit-lamp adapter (532 nm, 810 nm, and large spot 810 nm), a slit lamp and a custom cart.
Also exhibiting at the Iridex booth as a courtesy was Meridian of Switzerland. This company is distributing the former LASAG line of lasers, including the latest YAG version, the Microrupter V for posterior capsulotomies.
Laserex (Ellex Medical)
Laserex had two new lasers on display, its former LP 3016 YAG, now called the Super Q photodisrupter and a new compact LP3532 diode-pumped solid-state green photocoagulator, built for Laserex by Lumenis.
LightMed
This company, based in Taiwan, had several ophthalmic lasers on display including its LightLas 532 green laser, its LPULSA SYL9000 YAG photodisrupter, and its LightLas 810 nm diode TTT laser.
Lumenis
Just prior to the AAO meeting, Lumenis announced FDA approval of three new lasers, and it introduced a fourth still waiting for approval. These four are as follows:
The Novus Varia photocoagulator, the company claims, is the first diode-pumped solid-state laser to offer the spectrum of green, yellow and red light in one platform. The ability to instantly switch wavelengths and change power settings on a color touch screen provides flexibility during treatment, which is particularly beneficial in penetrating mild vitreous opacity, a sclerotic lens or mild vitreous hemorrhage. The Novus Varia photocoagulator is a diode-pumped semiconductor based platform, which unlike krypton or argon dye-based multicolor photocoagulators does not require external hookups for operation, frequent maintenance or special cooling. Retinal conditions covered in the FDA clearance include AMD, diabetic retinopathy, diabetic macular edema, retinopathy of prematurity and retinal vein occlusion.
The dual-purpose Selecta Duet integrates Lumenis’ patented selective laser trabeculoplasty (SLT) platform with advanced photodisruptor Nd:YAG laser technology in a single space-saving system. Selecta Duet features the Lumenis 532 nm glaucoma laser system, which the company said is the only SLT laser approved in the United States for treating open-angle glaucoma. Employing a 3-ns high-energy beam of light, SLT induces the same cell replacement mechanism as traditional argon laser therapy (ALT), but without causing thermal damage and scarring to the trabecular meshwork, the company said. The Selecta Duet also incorporates a 1064-nm Nd:YAG laser for capsulotomy. The Selecta Duet is built for Lumenis by Laserex.
The Novus Spectra is a 532-nm green diode-pumped solid state photocoagulation laser for treatment of a variety of retinal conditions. The company said the Novus Spectra has received FDA clearance for use in ophthalmology, ENT and dermatology applications. Weighing less than 18 pounds, the Novus Spectra delivers up to 2.5 W of power. Unlike argon-based systems, the laser does not require external hookups for operation, frequent maintenance or special cooling. The laser is compatible with previous Coherent delivery systems.
The Novus TTx is a diode-based 810-nm photocoagulator laser for treating AMD, still awaiting FDA approval.
Quantel Medical
This French company displayed its full line of ophthalmic lasers including its Viridis and Viridis Lite green photocoagulators; its Viridis Twin, combining a green and 810-nm diode laser; its Optimis YAG photodisruptor; a freestanding 810-nm diode, the Iridis; and its Activis 689-nm PDT laser.
Femtosecond lasers
Finally, both IntraLase and 20/10 Perfect Vision had femtosecond lasers on display, currently indicated only for cutting smooth flaps as part of bladeless LASIK, but eventually to be used for performing intrastromal ablation. The IntraLase FS laser, along with its IntraLASIK software, is FDA approved for cutting flaps, while the 20/10 Femtec laser still awaits 510(k) approval, expected by year’s end.
There are several differences between the two systems. The FS laser requires a suction ring and a disposable laser docking mechanism to perform the flap cut. The Femtec laser does not require applanation, retaining the natural shape of the cornea with no docking mechanism needed. The laser cuts the flap and places the hinge where the user defines it. Further, the company intends to couple its laser with a wavefront device currently sold by Visx as the WaveScan. In addition to producing a curved/contoured bladeless flap, the Femtec femtosecond laser is capable of both stromal lenticle formation and removal and of intrastromal ablation.
A note from the editors:
Irving J. Arons is a well-known and respected consultant who has been following and writing about the ophthalmic laser industry for 20 years. The opinions expressed in this article are his own and do not necessarily reflect the opinions of Ocular Surgery News, its editors or publisher.