CATT Study Update 9: The CATT Study is On Track

I first learned of the possibility of there being a comparative study of Avastin vs. Lucentis in June 2007. I then followed its progress until it finally became a reality in February 2008. The eighth installment traces how it became a reality in the author's own words.

According to an official with the CATT Study, it is on track and proceeding well. The 44 participating centers have recruited over 850 of the called-for 1200 enrollments and anticipate completing patient enrollment by the end of the year.

One-year results from the study are expected to be released in early 2011.

The study began enrolling patients in February 2008.

For more on this historic study, please see my prior Updates listed below:

CATT Study Update (June 2007)
The first hint that there might be a study.

CATT Study Update 2: Avastin vs. Lucentis – It’s Official! (September 2007)
Confirmation that the study will get underway.

CATT Study Update 3: Avastin vs. Lucentis – To Get Underway by Year’s End! (September 2007)
Additional information from the September meeting of potential clinical participants. Patient enrollment was supposed to begin by end of 2007 – it was delayed by announcements from Genentech

CATT Study Update 4: Avastin vs. Lucentis Study Ready to Roll (November 2007)
.UPenn gets its official website up and running.

CATT Study Update 5: First Official Listing of Clinical Trial Sites (January 2008)
NIH gets its website up and running.

CATT Study Update 6: Official Announcement of Trial Start from NEI (February 2008)
NEI releases press release announcing official start of the program.

CATT Study Update 7: An Interesting Commentary by Dr. James Folk (September 2008)
Interesting commentary by Dr. James Folk on the CATT Study.

CATT Study Update 8: The Story Behind The CATT Study (October 2008)
The story behind the story of how the CATT Study really happened – by the people who made it happen.

Femtosecond Lasers Proposed for Use in Cataract Surgery

As readers of this Journal know, I’ve been actively following developments in the use of femtosecond (FS) lasers. An old friend of mine, Larry Haimovitch, who contributes to Biomedical Business & Technology, just sent me a copy of his ASCRS 2009 report that was included in the June issue of BB&T. It features what he learned about the three companies proposing the use of FS lasers to perform cataract surgeries.

I requested and received permission from both Larry and the powers-to-be at AHC Media, the publishers of BT&T, to reproduce Larry’s report in its entirety.

Please note that the table numbers shown in the report are those used in the original writeup.


Femtosecond Laser Technology May Mark a Quantum Leap

By LARRY HAIMOVITCH

BB&T Contributing Editor

SAN FRANCISCO– The annual gathering of the American Society of Cataract and Refractive Surgery (ASCRS; Reston, Virginia) was held here this spring as specialists from three key ophthalmic specialties – cataract, refractive and glaucoma surgery – gathered to hear the latest clinical information.

With the economy reeling and laser vision corrections (LASIK) procedures down about 35% from last year, the expectation was that physician attendance would decline. However, the allure of a meeting in the spring in San Francisco, one of the great cities in the world, overcame the economic concerns and physician attendance was at record levels.

It is rare that any medical specialty experiences a revolution in new technology. More typically it is a gradual, evolutionary process. However, in a presentation titled “Initial Clinical Experience with a Femtosecond Laser System in Cataract Surgery” at a session on cataract removal techniques and technology, a potentially disruptive new technology was presented.

The talk, which was delivered to a captivated and standing room audience, was given by Zoltan Nagy, MD, an associate professor at Semmelweiss Medical University in Budapest, Hungary. He presented initial human results with a cataract removal system that has been developed by privately owned, venture capital-backed LenSx (Aliso Viejo, California). The company is describing this new technology as the “next-generation femtosecond laser phaco for refractive cataract surgery.”

Femtosecond (FS) lasers have been widely used in refractive surgery over the past several years. The technology was pioneered by IntraLase (Irvine, California) as a laser-based alternative to manual microkeratomes for the precise creation of a corneal flap prior to LASIK. After a slow start, the technology gained tremendous momentum and in the past couple of years had become the “standard of care” for LASIK procedures. This led to its acquisition in April 2007 by Advanced Medical Optics (AMO; Santa Ana, California) for $850 million.

AMO, which was purchased earlier this year for about $2.8 billion (including assumption of its debt) by Abbott laboratories (Abbott Park, Illinois), is now known as Abbott Medical Optics.

The removal of the cloudy natural lens, commonly referred to as a cataract, with today’s technology is manual and requires several steps. The surgical skill to do a “perfect” removal of the cataract is considerable and the procedure is fraught with risks. These adverse events, which are well-documented in the ophthalmic surgical literature, include posterior capsule rupture, the loss of endothelial cells, macular edema, retinal detachment, compromised zonules (ligaments that hold the lens in place) and perhaps most serious of all, the dreaded infection in the eye (endophthalmitis).

The basic concept behind this new approach is to convert the several manual and multi-steps in today’s cataract removal procedure into one that utilizes laser created, surgeon-controlled precision. The belief is that laser-accuracy will significantly enhance the results that are achieved by the surgeon’s hands.

Nagy outlined the several clinical applications of FS laser technology for the cataract removal procedure and these are shown in Table 4.


As an example, Nagy showed a comparison between the gold standard of today’s approach to cataract removal — ultrasonic phaco-emulsification — with the LenSx device. Phaco, which became popular about 20 years ago, is used in virtually every one of the estimated 3 million cataract procedures performed annually in the U.S. Nagy’s analysis showed that the LenSx system was extremely accurate for capsulotomy diameter, with 100% achieving the desired diameter. Conversely, manually performed procedures attained an accuracy of +/- 0.25 millimeters in only 20% of the time. Nagy also pointed out that the LenSx system required less power and effective phaco time to complete the procedure.

A less obvious but potentially huge benefit of this new technology is that it will provide a better capsulotomy prior to implantation of a “premium” intraocular lens (IOL). Premium IOLs encompass both multifocals and accommodating IOLs and enable most patients to either reduce or eliminate their need for reading glasses after cataract surgery. They are significantly premium-priced compared to standard monofocal IOLs and therefore patient expectations of an excellent outcome are far higher.

In part because most cataract surgeons are unable to perform a “perfect” cataract removal, the results from these premium IOLs has been mediocre. According to Andy Corley, global president of the Bausch & Lomb (B&L; Rochester, New York) Surgical Products division, the modest 5% domestic market penetration of premium IOLs is partially due to the limitations of today’s cataract removal process, which has caused some patients to experience disappointing results.

A list of the myriad potential benefits of a femtosecond laser cataract procedure is displayed in Table 5.


The cataract surgery market is a very large and significant ophthalmic market. According to MarketScope (St. Louis), the global market for cataract equipment and related disposable packs approximated $840 million in 2008, with the U.S. accounting for about one-third of this total.

Replacing manual cataract surgery with a highly precise FS laser could have dramatic impact on the competitive landscape in cataract surgery. Alcon Laboratories (Fort Worth, Texas) dominates this market with an estimated 60% global share. Other key players in the sector are AMO and B&L.

In addition to LenSx, which has assembled an outstanding and experienced management team and highly respected board of directors, two other private companies with VC backing are developing similar femtosecond laser technology.

LensAR (Winter Park, Florida) was founded by Randy Frey, who successfully started and sold his former excimer laser vision correction company, Autonomous Technologies. LensAR has also began its human clinical trials several months ago.

OptiMedica (Santa Clara, California) is expected to be another contender in this fledgling sector. This company has been in business for several years, successfully addressing the retinal market with its Pattern Scan Laser (PASCAL). Its proprietary approach to diabetic retinopathy photocoagulation features laser delivery technology that utilizes a short pulse duration, uniform predictable pulses and a precise pattern spacing. The benefits of the PASCAL technology and are shown in Table 6.



OptiMedica has demonstrated very robust growth in recent years, despite a price point for its laser that is approximately twice as much as conventional single-spot lasers. Clearly, its superior technology has enabled it to gain market share and become a force in this segment.

In addition to leveraging PASCAL into the glaucoma market, OptiMedica is ramping up a major effort to become a key player in the FS cataract market. The company has completed its pre-clinical studies and has recently initiated its human trials. Like LensAR and LenSx, OptiMedica hopes that its FS laser technology will enable it to perform an “all laser” procedure that will ultimately supplant manual cataract extractions.

All three companies will need to complete extensive clinical trials prior to entering the U.S. market but it appears that they will be able to file a 510(k) rather than a full PMA to achieve approvals. Based on their progress to date, it is unlikely that entry in the U.S. market will be attained until late 2010 or early 2011.


Glaucoma, Cornea programs

Before the exhibits opened, ASCRS sponsored two meetings, “Glaucoma Day” and Cornea Day” which provided attendees with the latest clinical, legislative and reimbursement from these two important areas.

Glaucoma is a group of disorders that is characterized by elevated intraocular pressure (IOP) that progressively damages the optic nerve in the eye. Without treatment, this can cause visual disability and eventually result in blindness. It affects an estimated 65 million people worldwide and is the second-leading cause of blindness globally. In the U.S., glaucoma currently afflicts at least 2 million Americans.

The risk of glaucoma increases dramatically with age. People who are 80 years old are nearly seven times more likely to have glaucoma than those who are 50. The U.S. Census Bureau has projected that Americans who are 60 and older will increase in number from 40 million to 76 million by 2025. Given this growth, the incidence of glaucoma is expected to increase to at least 3 million by the year 2020. This disease is typically managed medically, and it is estimated that a panoply of pharmaceuticals account for more than 90% of the treatment costs in the U.S. Glaucoma medications account for roughly 40% of the global market for ophthalmic pharmaceuticals, which exceeds $10 billion annually.

The shortcomings of the medical management of glaucoma are numerous and include:
1) Annual costs that for some patients can exceed $3,000.
2) Inconvenient dosage regimens.
3) Lack of efficacy, that is, the drugs often fail to control the elevated IOP.
4) Myriad side effects, including blurred vision, ocular irritation, pain, headaches, elevated blood pressure and gastrointestinal problems.

The disease is completely pain-free and asymptomatic, causing many patients to stop their regimens while their condition deteriorates. It is estimated that less than half of glaucoma patients are even aware they are afflicted. The result of all these barriers is that the compliance rate for patients on glaucoma medications is abysmally low, well below 50%. And, as one physician wryly observed years ago at an ophthalmic conference “drugs do not work when patients do not take them.”

The drawbacks of glaucoma drugs would appear to provide fertile ground for surgery and/or device based solutions. But, this has not occurred, as the mainstays of devices and surgery — drainage devices such as shunts, and filtration surgery (also known as trabeculectomy or trab) — have had modest efficacy and a relatively high level of adverse effects.

The number of trabs has declined from about 50,000 procedures in the mid-1990s to about 20,000 today. It is a complex surgery, and suffers from numerous adverse effects. The number of shunts has not grown either, as they are relegated as a “last resort” for patients in whom all other modalities have failed.

At this year’s “Glaucoma Day,” an interesting debate on the merits of selective laser trabeculoplasty (SLT) compared to medical management took place. SLT, which generally is regarded as the best form of laser therapy, creates tiny holes in the trabecular meshwork, allowing outflow from within the eye and thus reducing IOP.

Taking the side of promoting SLT was Douglas Rhee, MD, a glaucoma specialist from the Massachusetts Eye & Ear Infirmary (Boston), who provided a host of data to support the use of SLT as a primary option for treating glaucoma. He concluded by saying, “Based on effectiveness, compliance, impact on quality of life, risk comparison and cost, I think we’ve settled the argument of medical therapy over SLT.”

Defending medical management was Anissa Jamil, MD, from Glaucom Consultants North West (Seattle), who said that drugs are very effective for the vast majority of patients and are more reliable than a laser intervention.

During a Q & A period following the formal debate, the moderator asked Dr. Rhee what percentage of his patients actually received SLT as primary therapy. Much to the surprise of the audience, his answer was “less than 1% of the time.” When questioned as to why his treatment regimen so heavily favored drugs, he responded that “my patients expect me to prescribe drugs. This is a cultural expectation.” This rather surprising revelation perhaps best explains why prescription drugs utterly dominate the glaucoma therapy landscape today.

One of the more interesting concepts discussed during the program was the possible use of phacoemulsification (ultrasonic emulsification of the natural lens) as a means to lower IOP. It is estimated that in the U.S. about 10% of patients have co-existing cataracts and glaucoma.

There have been numerous studies over the past decade suggesting that phaco can lower elevated IOP. For example at last year’s ASCRS annual meeting in Chicago, Brooks Poley, MD, presented a retrospective study on nearly 600 eyes of the long-term effect of phaco in normotensive and ocular hypertensive eyes. Poley and colleagues found that the eyes with the highest pre-surgical intraocular pressure showed the biggest improvement. He compared this study with the landmark Ocular Hypertensive Treatment Study (OHTS), which was a prospective trial that examined the use of prescription eye drops in more than 1,600 patients, who were followed for over five years.

In the OHTS trial, 817 patients were treated with glaucoma drops and 819 were not. Of those treated with medication, 4.4% converted to glaucoma, compared to 9.5% converted to glaucoma not treated with drops. This compares unfavorably to the 1.1% the rate of glaucoma conversion after phaco alone.

After his presentation at ASCRS a year ago, Poley was adamant about phaco vs. drugs, saying that “drops don’t solve the problem, they just slow the progression. On the other hand . . . the patients that had ocular hypertension, their pressures went down after surgery for the 10 years of our study. We returned them to a normal status. How many patients treated with drops did that? None. That’s mind-boggling.”

These data were corroborated by Reay Brown, MD, who was inspired to conduct his own study to see how phaco reduces IOP. His data was presented at the March meeting of the American Glaucoma Society (AGS; San Francisco).

Brown and his colleagues examined 83 patients with angle-closure glaucoma or narrow angles who had phaco and IOL implantation. They found that 90% of the patients showed an improvement in pressure. At this year’s ASCRS, Brown said that “if you did a multicenter study and found what we had found in our highest pressure group, the FDA would approve cataract surgery as a treatment for angle-closure glaucoma. In other words, if cataract surgery came in a bottle, the label could say that cataract surgery has been found to be effective in the treatment of angle closure glaucoma.”

Several device companies, many venture-capital backed, are hoping to impact the glaucoma market with innovative devices. Some of these companies exhibited at this year’s ASCRS meeting, while some are too early stage to be making a public presence.

Prominent companies include iScience Interventional (Menlo Park, California), which features an innovative and new category of therapy, which it calls interventional ophthalmology. This encompasses microcatheter-based therapies designed to access a wide range of anatomical structures within the eye to aspirate ocular fluids or deliver sterile ophthalmic solutions to the eye. Specific to glaucoma, iScience features iCat canaloplasty, which is the first and only microcatheter-based procedure that safely reduces intraocular pressure (IOP) and dependence on medications in open-angle glaucoma patients. While specific information is not available, it is believed that this procedure is catching on slowly, due to its steep learning curve.

The company recently announced the closing of a Series “F” venture capital financing raising more than $20 million.

Another VC-backed company is Glaukos (Laguna Hills, California), which has developed an
implantable titanium stent called the iStent. This tiny implant, with a 120 mm lumen, is implanted through a tiny corneal incision and positioned so that aqueous fluid can bypass the clogged area of the eye and flow out through another route called Schlemm’s canal. Glaukos has completed its U.S. pivotal trial and filed its PMA in late 2008. Based upon this filing date, final FDA approval could be received in late 2009 or early 2010. The company’s initial marketing strategy will be to address patients who are undergoing a cataract procedure and who have an elevated IOP. These patients would receive an iStent concomitant to their cataract removal and IOL implant.

Another VC-backed company is Transcend Medical (Menlo Park, California), which has also developed a stent-like device. The company’s describes glaucoma as “ophthalmology’s greatest unmet need” and is hoping to begin its U.S. clinical trial in the near future. Like iStent, Transcend intends to initially address the cataract patient with elevated intraocular. The “perfect” glaucoma device, as described by the company, is shown in Table 7.





About the Author

Larry Haimovitch is president of Haimovitch Medical Technology Consultants, a Mill Valley, CA-based health care consulting firm. His firm specializes in the analysis of the medical device industry, with particular emphasis on the current trends and the future outlook for emerging medical technology. The current areas of emphasis are ophthalmology, interventional medicine (cardiology, electrophysiology, radiology and neuroradiology), urology, ophthalmology, minimally-invasive surgical technologies and medical lasers.

He can be reached at: Larry Haimovitch

Menu – Part 13: A Few Updates and Some New Posts

Since the last menu posting, I have added two updates for AMD; a new approach for treating myopia with femtosecond lasers; a list of my private client studies while at Arthur D. Little and with Spectrum Consulting; revisited thermal keratoplasty as a technique for treating myopia; and posted two columns, one on my early contact lens days written for Vision Monday and the second on cast-molded eyeglass lenses, done for Ocular Surgery News.

First, the AMD Updates:

AMD Update 4: Does Visualizing RPE Cells Hold the Key to Understanding AMD?

David Williams and his team at the Center for Visual Sciences at the University of Rochester came up with a method of visualizing RPE cells in the retina in vivo, using adaptive optics. This could be a breakthrough in understanding how drugs and other treatments for AMD effect these important cells in the retina.


AMD Update 5: Emerging Technologies for Treating AMD

In this posting, I summarized some of the important techniques and technologies under development in the treatment of AMD – including the Ellex 2RT retinal regeneration technique; the potential use of stem cells to regenerate healthy retinal tissue by two research efforts; and a recap of the visualization techniques described in AMD Update 4 that could play an important role in showing the changes in RPE cells affected by some of these techniques.


Another Approach to Intrastromal Ablation

Dr. Rupal Shah, responding to my history of ISA*, told me of her research in using a femtosecond laser to form and remove a lenticle in the corneal stroma to correct myopia. She kindly allowed me to reproduce a report she had written on her research, describing her use of the Zeiss-Meditec VisuMax femtosecond laser in the FLEx technique (Femtosecond Lenticle Extraction).

* Intrastromal Ablation: A Technology Whose Time Has Come?


Private Client Studies – Arthur D. Little (1972 - 1994) and Spectrum Consulting (1994 - 2001)

In addition to the hundreds of articles and columns written over my 30-plus years of consulting, I led over 100 client-sponsored studies, covering a variety of topics. In this posting I have listed the titles of most of the reports I either wrote or was in charge of producing.


Thermal Keratoplasty Revisited

In reading about the work being done by John Marshall and his colleagues at King’s College in London, as well as by old friend David Muller with his new company Avedro, in trying to use microwave energy to flatten the cornea to correct myopia, I was reminded that I had written about earlier attempts do the same thing with a variety of thermal techniques. I looked up the column I had written for Ophthalmology Management in October 1990 and decided it was time to reproduce it on the web.


Vision Monday Columns: A Bit of Nostalgia

In searching for the columns I had written for Vision Monday back in the early 1990s, I came across this piece that described my early history with soft contact lenses. Again, I decided that it should be available online for contact lens historians and researchers, so I posted it to my online Journal.


Cast-Molded Eye Glass Lenses

I recently heard from a couple of old friends back from my contact lens days. They are starting a new company, QSpex Technologies, to produce ophthalmic lenses in an eye care professional’s office. I had done some consulting work on in-office plastic lens molding in the early 1990s and had also studied the high-index plastic lens business. I wrote about one of the innovative in-office lens molding companies in an Ocular Surgery News Technical Update column in 1993, and my friends were wondering if I still had a copy of the column. I managed to find it and have reproduced it on my Journal.

Another Approach to Intrastromal Ablation

I have heard from several people since I wrote about intrastromal ablation. Some believe that incisions in the stroma to affect corneal shape can be done, as described by Dr. Ruiz, and others believe, in the long term, that it will not succeed.

I have just heard from Dr. Rupal Shah from the New Vision Laser Centers in India. She is amongst the latter. However, she has been involved over the past ten months in a lenticle removal technique using the VisuMax Femtosecond laser and has agreed to allow me to reproduce the paper she has written about this procedure in my Journal.

Note: The technique of forming and removing a lenticle from within the cornea is not a new approach. I wrote about developmental work on shaped lenticles by IntraLase in my 2000 AAO Meeting Roundup, that appeared in the January 15, 2001 issue of Ocular Surgery News. However, as has been pointed out by Dr. Shah, the method of planar applanation and the strong scleral suction used by the Intralase could compress the cornea in an unpredictable way, and therefore reduce the chances of success with such a procedure. The curved interface of the VisuMax Femtosecond Laser, as shown below in her article, along with the light corneal suction and low pulse energy of the VisuMax system seems to be necessary to get good results with such a technique.


Here is what Dr. Shah has written:

FLEx®- A New Paradigm for Laser Refractive Surgery

Dr. Rupal Shah, Clinical Director, New Vision Laser Centers-LaseRx

Trokel and Srinivasan first proposed the use of the excimer laser for corneal photoablation in 1983. Corneal Photoablation involves breaking the intermolecular bonds between tissue molecules, thus enabling precise removal of corneal tissue from the surface of the cornea. In 1988, the first sighted eyes were treated for refractive errors with the excimer laser using a procedure known as photorefractive keratectomy (PRK). PRK was performed by first removing the epithelial cells from the cornea, and then ablating a precise lens from the cornea, using repeated pulses of the excimer laser. PRK allows the safe and predictable correction of refractive errors. However, the procedure has certain limitations, particularly because the corneal epithelium is removed during the procedure. There is extreme pain for the first 24 hours after the procedure, visual acuity is impaired for several weeks after the procedure, there is typically a hyperopic shift during the first few weeks after PRK, and finally there is the risk of corneal haze and regression, particularly in the case of large refractive error correction.

To overcome these limitations, a new procedure called Laser In-Situ Keratomeleusis (LASIK) was developed in the early 1990’s. LASIK married the excimer laser with the microkeratome, an instrument designed for lamellar keratectomy. In LASIK, the microkeratome is used to create a hinged flap at about 130 microns depth on the cornea. The flap is then lifted to one side, and subsequently, excimer laser keratectomy is performed on the stromal bed. After the keratectomy is finished, the flap is then replaced, where it sticks back in its original location, initially by surface tension forces, and later by epithelial “glue” around the flap edges. LASIK overcame most of the limitations of PRK, and thus led to a sharp rise in the popularity and appeal of laser vision correction, both for physicians and patients.

It quickly became clear that the Achilles heel of the LASIK procedure is the microkeratome itself. It is prone to error, particularly due to the demands placed on what is a really precise but ultimately mechanical instrument. Free Caps, incomplete flaps, irregular flaps, button-hole flaps, displaced flaps, epithelial abrasions and other complications occur in approximately 1% of all LASIK cases. In most of these cases, it is not surgeon error but a result of malfunction, or mechanical error or other infirmities (related to blade quality, for example). In addition, the microkeratome flap is prone to thickness variation. This increases the risk of corneal ectasia, particularly for large corrections and thin corneas.

The Femtosecond Laser was introduced to overcome these limitations of mechanical microkeratomes. The Femtosecond Laser is capable of delivering laser energy in an extremely short time (femtosecond pulse width) and very tightly focused in space (in the μm regime). It causes photodisruption within corneal tissue, converting a tiny volume of corneal tissue into a gas bubble, with every laser pulse. When millions of such pulses are laid down in a precise plane at a fixed depth around the center of the cornea, it is possible to create a lamellar slice of the cornea. Thus, the Femtosecond Laser can be used to substitute the mechanical microkeratome in the LASIK procedure. Over the last few years, the Femtosecond laser has developed an excellent safety profile, and is increasingly replacing the mechanical instrument as the instrument of choice for making LASIK flaps. It has several advantages over mechanical microkeratomes in this respect-the flap thickness is more precise, there is little or no chance of flap complications such as button-holes, free caps and irregular flaps, and there is less chance of a displacement, since the Femtosecond laser creates a deep gutter in which the flap “fits” back, thus making it less likely that eyelid movements and such will displace the flap from its place. There is also some evidence that flaps made with the Femtosecond Laser induces lesser higher order aberrations in the eye.

While the Femtosecond Laser is very useful for the LASIK procedure, it is not without issues of its own. It means that the surgeon or eye hospital must invest in two rather expensive lasers, i.e. the Femtosecond Laser and the Excimer Laser. The Femtosecond Laser is used to make the flap, while the Excimer Laser is used to ablate the corneal surface to provide the refractive correction. They must pay for the consumables, license fees and maintenance of two lasers. There are also workflow issues related to a two step procedure as well. The patient must at best be moved only from one laser to another while lying on a pivoting patient bed. Due to the two laser configuration extra space is required in the surgery theatre, and the overall procedure time for a complete LASIK procedure is increased. Moreover, now that the Femtosecond Laser has removed the likelihood of flap problems during LASIK, attention is drawn to the limitations of the excimer laser itself. The excimer laser performance is affected by environmental factors such as humidity, there is peripheral energy loss during laser ablation, and the laser ablation is affected by the environment and other factors like corneal hydration, humidity, and the presence of organic vapors.

Recently, Carl Zeiss Meditec has introduced a new Femtosecond Laser into the ophthalmic market, the VisuMax® (Fig 1). Unlike other popular Femtosecond Lasers, like the Intralase (e.g. FS60, iFS) or the Zeimer Femto LDV, the VisuMax® has a curved (as opposed to a planar) contact glass (Fig 2). It has special optics to create a very precise spot focused in the cornea with extremely high accuracy (Fig 3). The scanning and focusing optics of the VisuMax® make it capable of placing the laser spot at a specified 3 dimensional position almost anywhere in the cornea. It is already a popular instrument to make LASIK flaps.


Figure 1. Zeiss-Meditec VisuMax FS Laser



Figure 2. Curved Contact Glass of the VisuMax Laser



Figure 3. Difference Between Conventional Optics and Zeiss Optics

However, the Visumax is also capable of a procedure, which is called Femtosecond Lenticule Extraction (FLEx®). FLEx® first involves the calculation of the kind of lenticule which needs to be removed for correcting the refractive error of the patient. The VisuMax® is then used to lay down pulses within the corneal stroma to form the lenticle, illustrated in the four steps shown in Fig 4. In the first step, the lenticule backside cut is created. The second step creates the lenticle frontside cut. In another step, the VisuMax® is used to lay down pulses which separate the anterior surface (upper cut) of the lenticule from the stroma. The upper cut of the lenticule is extended a fraction of a millimetre beyond the edge required for the lenticule. It thus serves as the flap. In the third step, the flap side cut is then created to make a hinged flap.



Figure 4. Steps in Formation of the Lenticle

The flap is lifted (Fig 5), and the lenticule extracted from the stroma (Fig 6 & 7). The flap is then replaced (Fig 8). The corneal tissue which otherwise would have been ablated off by the excimer laser is removed physically as a whole in the FLEx® procedure (lenticule extraction instead of tissue ablation). Thus, there is no need for an excimer laser for the refractive correction. FLEx® represents the first “All in One” procedure which uses only the Femtosecond laser to complete all steps of the LASIK procedure.



Figure 5. Flap Pushed Aside



Figure 6. Lenticle Lifted



Figure 7. Lenticle Removed



Figure 8. Flap Replaced

FLEx® promises to change the way eye surgeons perform LASIK. It requires investment in only one laser, and paying for only one laser’s consumables and maintenance. It simplifies workflow within the laser suite. There is less total energy incident on the cornea, and there are none of the limitations of excimer lasers, such as the dependence on corneal hydration levels and environmental humidity. It thus represents a possible paradigm shift in the way laser vision correction is carried out.

Since 2006, Dr. Walter Sekundo and Dr. Marcus Blum have performed FLEx® in Germany on more than 250 eyes, with a follow-up period of more than 2 years for some cases. They established the initial feasibility and safety of the procedure. The Femtosecond laser, of course, does not need new safety tests related to laser-tissue interaction, since it is routinely used for making flaps on the cornea. New Vision Laser Centers’ Vadodara Center was the third center in the world to start FLEx® and, moreover, also represented the first high volume site to test reliability and performance for high patient throughput clinical environments. We have recently completed a prospective study on 250 eyes, and have at least one month follow-up for all patients. This is an ongoing pre-commercial study supported by from Carl Zeiss Meditec. All patients were informed that the procedure was relatively new, with very little worldwide experience, and with results that were not very certain. A single surgeon (Dr. Rupal Shah) did all the procedures. All the procedures were done within a 5 month period, starting from August 2008. Complete pre-operative and post-operative testing was done.

We treated myopia and myopic astigmatism, with a high limit of -10 Diopter Spherical Equivalent. Theoretically, there is no limit on the kind of error that could be treated. Practically, the currently available software limits the treatments to -10 Diopters for safety reasons during the approval phase.

The results of the study are quite satisfying. The refractive stability is excellent. There was hardly any change in the refractive status of the patients from the first day onwards. The refractive predictability is also excellent. 96% of all eyes at one month were within a half diopter of the intended correction, which is at least comparable to or superior to all U.S. FDA trials of excimer lasers. There was a very slight tendency towards overcorrection in the low myopes and a very slight under correction for the high myopes. Interestingly, this was all we found in terms of nomogram optimization so far, although we started with a zero nomogram! It demonstrates the capabilities of the FLEx® and shows that FLEx® is more neutral and less sensitive to factors that normally affect excimer laser ablation (e.g. hydration state of the cornea). At three months, more than 85% of all eyes had an uncorrected visual acuity which was the same or better than their preoperative best corrected visual acuity. At three months, more than 90% of eyes had a best corrected visual acuity which was better than or the same as their pre-operative best corrected visual acuity. However, at one month, this figure was only 67%, which indicates that the visual acuity recovers more slowly than with standard LASIK. There were very few adverse events. One eye suffered from DLK, which resolved over time, while we aborted treatment in another patient, because of a suction loss appearing during the procedure. There were hardly any induced wavefront aberrations, and also an excellent topography outcome (Fig 9).



Figure 9. Topography Maps for an Eye with High Myopic Astigmatism

Thus, FLEX® compares very well with standard LASIK on stability, predictability, efficacy and safety. However, the visual acuity at the time being recovers more slowly than with standard LASIK. With an improvement in the laser energy parameters, as well as an improvement in surgical technique, visual recovery improved even during the study itself. However, we continue to do more work to find out the origin of the slower visual recovery, and a correction thereof. We are also doing more studies to study the biomechanical stability of the cornea post FLEx®, since there are good reasons to believe that the biomechanical stability after FLEx® would be better than with standard LASIK.

In conclusion, FLEx® represents a completely new way of doing laser refractive correction. It takes a familiar technology (Femtosecond Laser) with an excellent safety profile, and uses it exclusively for refractive correction, thus eliminating today’s two laser solution. Although studies in terms of hyperopia correction or the implementation of methods to perform retreatments are currently still ongoing, we clearly see FLEx® becoming part of the refractive surgery main stream. Based on our current results, FLEx® seems to represent a paradigm shift on the way in the field of refractive surgery.








Dr. Rupal Shah.

Dr. Shah is the Clinical Director of New Vision Laser Centers, and LaseRx, Institute of Laser Medicine. She practices in both Mumbai and Vadodara, India and is a consultant for Carl Zeiss Meditec.

Dr. Shah can be reached at: Email: Dr. Rupal Shah


Addendum: Since the above article was prepared, Dr. Shah informed me that she has now treated over 350 eyes in this study. Today, with optimization of laser parameters, she gets excellent refractive results, but visual recovery is also nearly similar to standard Femto-LASIK.

PRIVATE CLIENT STUDIES – Arthur D. Little (1972 - 1994) and Spectrum Consulting (1994 - 2001)

In addition to the hundreds of articles and columns written over my 30-plus years of consulting, I led over 100 client-sponsored studies, covering a variety of topics. Here are the titles of most of the reports I either wrote or led the effort in producing. Some of the titles have been partly redacted to prevent identification of the client.

Note that nearly all of the studies until 1985 involved contact lenses, at which time I began consulting in medical lasers.

(Bolded studies can be found online.)

1972
● Worldwide Review of Soft Contact Lenses Made of Hydron (B&L Soflens), August 1972

1974
● Technological Developments in Ophthalmic Lens Materials and Processes, February 1974

1976
● The Contact Lens Business--An Emerging Opportunity, June 1976
● Investigation of the Coating Buildup Problem on Soft Contact Lenses, November 1976
● The Soft Contact Lens Business--Profile of an Opportunity, December 1976

1978
● Technical Assessment of a Soft Contact Lens Automated Machining Center, April 1978

1979
● The Contact Lens Solutions Business: An Opportunity for -- --, January 1979
● An Evaluation of Wesley-Jessen's Contact Lens Technology, August 1979
● Identification of a Soft Contact Lens Licensing Partner for -- --, November 1979
● Current and Future Developments in the Contact Lens Industry, December 1979
● An Evaluation of Titmus Eurocon's Contact Lens Technology, December 1979

1980
● A Technology Forecast: Vision Devices 1980-2000, January 1980
● The Development of an Improved Eyeglass Frame Material and Manufacturing Process, March 1980

1981
● Projections of the Markets for Hard Gas Permeable Contact Lenses, January 1981
● The Technical Evaluation of Frontier Contact Lenses Inc., January 1981
● An Overview of the U.S. Contact Lens Business, January 1981
● The Development of Novel Low Cost Disinfection Systems for Soft Contact Lenses, February 1981
● A Worldwide Review of Hard Gas Permeable Contact Lenses, February 1981
● Technical Evaluation of a New Contact Lens Manufacturing Process, February 1981
● An Analysis of the Contact Lens Business of -- --, March 1981
● A Worldwide Overview of the Ophthalmic Industry for the Scottish Development Authority, June 1981
● A Comparison of Low, Medium, and High Water Content Contact Lens Systems, July 1981

1982
● Technical Evaluation of an IOL Research and Manufacturing Operation, January 1982
● The Offering of a Contact Lens Company to Prospective Buyers, Winter 1982
● The Offering of a Retail Optical Business (Inventory, Lab Equipment and Fully-Equipped Dispensing Offices) to Prospective Buyers, Spring 1982
● The Development of a Low Cost Chemical Disinfection System for Soft Contact Lenses, February 1982
● An Overview of Diagnostic and Surgical Ophthalmic Equipment, July 1982
● Current Developments in Hard Gas Permeable Contact Lenses, December 1982

1983
● Assessment of a New Contact Lens Manufacturing Technology, January 1983
● Evaluation of a Soft Lens Cleaning Device, February 1983
● Technological Developments in the U.S. Contact Lens Industry, April 1983
● Near Term Trends in the U.S. Contact Lens Industry, June 1983
● Technological Assessment of -- --, October 1983
● Packaging of a Peroxide Neutralization System, November 1983
● Analysis of R&D and Regulatory Capabilities of Major U.S. Contact Lens Companies, December 1983

1984
● Background Papers on Soft Contact Lenses and Care Products, January 1984
● A Background Report on the Contact Lens Industry in the U.S., January 1984
● The Establishment of a Transfer Price for Contact Lens Blanks, January 1984
● Development of a Tensile Testing Method for Contact Lens Materials, January 1984
● An Overview of Trends and Developments in Eyeglasses and Contact Lenses, March 1984
● The Offering of a Contact Lens Laboratory and Fitting Clinic, April 1984
● The Establishment of a Transfer Price for Intraocular Lenses, April 1984
● The Outlook for the Ophthalmic Products Industry, May 1984
● An Assessment of Competitive Soft Lens Tinting Technologies, June 1984
● Current Trends in the U.S. Contact Lens Industry, September 1984
● Survey of Practitioner Attitudes Toward Cosmetic Extended Wear, November 1984

1985
● Comparison of Estimated Soft Lens Manufacturing Costs, February 1985
● An Update of Near Term Trends in the U.S. Contact Lens Industry, May 1985
● Contact Lens Manufacturing Techniques, August 1985
● The Offering of a New Soft Bifocal Contact Lens for Licensing, September 1985
● Entry Strategy to the U.S. Contact Lens Market, October 1985
● Update of the U.S. Ophthalmic Industry, November 1985
● Technology Assessment of the Green YAG Laser, November 1985

1986
● The Outlook for Refractive Surgery: The Impact of the LRK Technique, March 1986
● The Valuation of an IOL and a Surgical Instrument Companies, June 1986
● The Valuation of an Ophthalmic Products Company, November 1986
● A Brief Study of the CL Market in Japan, November 1986
● The Valuation of an Ophthalmic Instrument Company, December 1986

1987
● Ophthalmology Technical Alert Service, 1987
● An Overview of the Presbyopic Market Place: The Prospects for a New Viable Bifocal Contact Lens Design, February 1987
● A Detailed Survey of the CL Market in Japan, February 1987
● The Outlook for Viscoelastic Substances in Ophthalmology, May 1987
● An International Overview of Contact Lenses, June 1987
● The Nature and Evolution of the Soft Contact Lens Industry in the United States, August 1987 (B&L vs. the IRS)

1988
● The Current and Theoretical Production Capacity of the U.S. Contact Lens Industry, April 1988
● Evaluation of CooperVision, June 1988
● Medical Laser Overview, August, 1988
● Technical and Market Analysis of -- --, July 1988
● Ophthalmic Market Overview, September 1988
● Technology Overview: Ultrasound Catheter Market, December 1988

1989
● Ophthalmic Surgical Equipment Overview, March 1989
● U.S. Market for Soft Contact Lens Lubricant/Rewetting Drops, March 1989
● Contact Lens and Care Product Market Overview, May 1989
● Update: The Outlook for Laser Refractive Surgery, August 1989

1990
● Development of a Manufacturing Plan for Medical Lasers: Product Selection, January 1990
● Technology Overview: Phoenix Laser Systems, March 1990
● Current Developments in Laser Refractive Surgery, July 1990
● Opportunities for Collaboration, September, 1990
● An Evaluation of a New Eyeglass Lens Molding Process, Phase I: Technology Overview, September 1990
● Overview of High-Index Plastic Eyeglass Lens Materials, November 1990
● Background Information on the Contact Lens Industry, December, 1990
● Profitability in the Ophthalmic Industry, December, 1990

1991
● Contact Lens and Care Product Overview, January, 1991
● Current Developments in Laser Refractive Surgery, March 1991
● An Overview of the U.S. IOL Industry, April 1991
● Ophthalmic Industry Overview, August 1991
● Overview of Current Developments in Refractive Surgery, August 1991
● Technology Overview: Phoenix Laser Systems, October 1991
● Overview of the IOL Industry, September 1991

1992
● Excimer Lasers in Surgery, February 1992
● Current Developments in Laser Refractive Surgery, March 1992, updated July 1992
● New Ophthalmic Laser Technologies, June 1992
● Historical Overview of Ophthalmic Lasers in the Mid-1980s (legal case), July 1992
● Medical Laser Technology Alert Reports, monthly, July 1992 - April 1993

1993
● Technology Overview and Strategic Partnering for Unique Medical Laser Product Company, September 1993
● The Outlook for Refractive Surgery Centers, September 1993
● A Cost Comparison of Refractive Surgery vs. Eyeglasses and Contact Lenses, October 1993
● An Overview of Current Developments in Refractive Surgery, December 1993

1994
● An Assessment of a Laser-based Method to Alleviate Heart Attacks, February 1994
● The Outlook for a Laser-based Technique to Cure Psoriasis, March 1994
● Current Developments in Laser Refractive Surgery, August 1994, updated April 1995
● An Assessment of an Unique Laser-based Technique to Diagnose Severe Burns, August 1994

1995
● Estimated Market for a New Mid-IR Laser Delivery Fiber, February 1995
● The Outlook for Refractive Surgery, March 1995
● An Analysis of the Hawaii PRK Market, May 1995

1996
● Potential Laser (and non-laser) Sources for Activating Photofrin, March 1996
● Search for a Diode Laser Source for Activating Photofrin, April 1996
● A White Paper -- Laser Hair Removal: An Application Whose Time has Come, October 1996
● Worldwide Market Overview of Ophthalmic and Dermatologic Lasers, December 1996

1997
● U.S. Market Opportunities for ICON Centers for Cosmetic Surgery, March 1997
● Refractive & Cosmetic Surgery -- Any Synergies?, November 1997
● An Overview of the Medical Laser Industry, December 1997

1998
● Worldwide Medical Laser Marketplace, May 1998
● An Investigation into the Use of "Bermuda Cards", July 1998
● Review of Photodynamic Therapy for Treating ARMD, December 1998

1999
● Update: Trends in Refractive and Cosmetic Laser Surgery, November 1999
● An Evaluation of ThermoLase's Technologies, December 1999

2000
● A Look at the Future of Refractive Surgery, February 2000

2001
● A Brief Overview of the Opportunities for a 3 micron Medical Laser System, July 2001
● Adoption Rates of Soft Contact Lenses, IOLs, and Refractive Surgery, September 2001

Cast-Molded Eye Glass Lenses

I recently heard from a couple of old friends back from my contact lens days. They are starting a new company to produce ophthalmic lenses in an eye care professional’s office. I had done some consulting work on in-office plastic lens molding in the early 1990s and had also studied the high-index plastic lens business. I wrote about one of the innovative in-office lens molding companies in an OSN Technical Update column in 1993, and my friend was wondering if I still had a copy of the column.

I managed to find the column I had written on my old computer, and since my friends were developing a new company based on this type of process, I decided to reproduce the original column as it relates the history of in-office lens casting.

As a salute to my old friends Tim Rogers and Steve Martin, and their new company QSpex Technologies and its Lens Transformation Process, here is what I wrote about Innotech and its Excaliber lens molding system back in the March 15, 1993 issue of Ocular Surgery News.


TECHNOLOGY UPDATE

The Excalibur SurfaceCasting System from Innotech: "He who has the sword shall be King!"

Irving J. Arons
Ophthalmic Consulting Group
Arthur D. Little

Over the years, several groups of innovative people have attempted to bring techniques for making "instant" ophthalmic lenses in the office or dispensary to market. These attempts reached their peak about five years ago with the advent of LensCrafters' advertisements for "1 Hour Service".

Since the LensCrafter claims to make most Rxs in about an hour were based on having an in-store processing lab, to stay competitive both independent dispensers and other chain retailers explored the options for making "fast" lenses offered by the likes of Vision Sciences and Technavision, the then (barely) surviving in-the-office lens casters.

Technavision, originally known as Orplex, was born in 1982, while Vision Sciences came along a few years later. And then there is Henry Earle, the grandpappy of lens casting, with his Duralens process, which was started in the early 1950s. Later on in 1988 Larry Joel developed his "Fast Cast" system, which he sold to Pearle Vision allegedly for $25 million. Pearle is still working to get the bugs out of the system before releasing it to its retail outlets.

Along the way, both Henry Earle (in about 1985) and Norman Rips, perhaps a year or so later, each developed wafer bonding methods -- the gluing of a thin lens carrying the Rx and/or bifocal correction onto a base stock lens. The Rips' system, originally called the Krom-X process, is now known as the Dicon Instalens process and is still being sold, now by Dicon/Visimed (San Diego). And other wafer systems are being developed by such as Tandem Optics (Rochester, NY), Pentax (Japan) and Sola Optical (Petaluma, CA).

Now, a new company, Innotech (Roanoke, VA), founded by Ron Blum and a group of people formerly associated with Vision Sciences, have come up with a hybrid technology, half way between the old thermal cast molding technique and the newer UV adhesive wafer technology. It is called SurfaceCasting using the Excalibur Office-Based Lens Fabrication System.

This patented process involves a single glass mold -- with either a progressive or flat-top 28 design, a proprietary, thin CR-39-based backup wafer (single vision lens) or Power Plate as the company calls it, a specially formulated CR-39 liquid monomer containing UV curing initiators, and a UV curing apparatus.

In use, two flat-top or progressive molds are placed into a holding tray, about a teaspoonful of the monomer is added to each mold, and the appropriate power plates positioned on top. No gaskets or pressure holding devices are used. The sandwiches are placed into a small UV curing chamber polymerizing the resin which bonds to the power plate backup wafer (back surface of the lens), and assumes the shape (and power) of the mold surface (front lens surface). This resin polymerization process takes about 27 minutes. The cured sandwiches are then placed into a demolding apparatus which separates the finished lenses from the molds in about two minutes. The whole process to produce a pair of bifocal or progressive lenses, including selection of the appropriate molds and wafers, assembly, curing, and demolding, takes about 35 minutes.

According to industry experts from LensCrafters and Texas State Optical who have observed the process close up, operating the system at three beta sites each, the system produced first quality, thin lenses (that the company claims exceed ANSI lens standards) at affordable prices. Innotech claims that the new UV processed lens is about 20% harder than conventional CR-39 lenses and therefore may not require a scratch-resistant coating. Innotech further claims that lenses made using the technique can save a dispenser an average of about 65% of the cost of buying progressive lenses from a lab, and about 35-40% of the cost of typical flat tops. (In the company's calculations, this worked out to about $15 per pair versus $45 for unfinished 75mm progressives and $12 versus $18 for the 75mm flat tops.) Further, the finished lenses can be hard coated, tinted, and anti-reflection coated similarly to standard CR-39 lenses.

For now, a series of 108 core molds can be obtained to make either flat-top 28s (54 molds) or their proprietary progressive design lenses (another 54 molds), with spherical powers from -4.00D to +4.00D, cylinder powers of -0.25 to -2.00D, and add powers of +1.00 to +3.00D. The progressive lens design is a "semi-soft" style according to company executives.

As noted, the system has been beta tested for a minimum of three months at seven sites, including three LensCrafters and three Texas State Optical retail locations. It will sell for approximately $32,000, plus an additional $3000 for an initial supply of monomer and a customized inventory of power plates depending on the practice size and lens type usage. The price includes two days training, service and a one-year warranty. The company claims the system is capable of producing up to 12 pairs of multifocal lenses per day, and that a typical dispenser using the Excalibur SurfaceCast System to produce 6-8 pairs of multifocals per day would pay for it in less than 2 years.

The Excalibur is self-contained with a microprocessor control unit, built in resin dispenser (and reservoir), curing chamber, and mold and wafer inventory holding drawers.

For those interested in seeing the system up close and personal, it will have its first public demonstration at Vision Expo in New York city at the end of March.


A number of question remain to be answered:

● Will high-index resin material and back up wafers be available any time soon to produce high-index lenses?

● The company claims to be able to produce "thin" lenses. How thin is thin?

● What is the life time of the molds? For how many cycles can they be used? What is the cost of replacement molds?

● What is the real cost per lens pair when labor, mold replacement, cleanup and other miscellaneous costs are included?

● What is the yield of high quality lenses? How much breakage/spoilage can be expected over a years usage?

● What skills are required to run the system? Can a lab tech run it, or is special training/education required?

● Will proprietary progressive lens designs such as Varilux be made available in the future?


The company's R&D plans are to extend the SurfaceCasting technology to include production of IOLs, bifocal and toric contact lenses, and consumer and aerospace optics in the future.

Although our initial impression of the system is that it appears promising, perhaps even "revolutionary", as with all things new, only time will tell if this "better mousetrap" will conquer the world (i.e., "He who holds the sword", etc.). But, with the announced initial sales of over 135 systems to LensCrafters and TSO, the company is off to an auspicious start!

THERMAL KERATOPLASTY REVISITED

I recently read about news coming out of the 2009 ASCRS Meeting that John Marshall and his colleagues at King’s College in London were trying to use microwave energy to flatten the corneal curvature in a form of refractive correction.

Marshall reported that his group had hypothesized that the use of microwave energy could be targeted to “shrink” stromal collagen fibrils, both superficially and centrally within the cornea to correct myopia. This use of targeted microwaves could also be used in a peripheral ring to induce steepening of the cornea to correct hyperopia.

As I read the report, I was reminded that I had written about this very same thing nearly 20 years ago, in a “Technology Update” column written for Ophthalmology Management in October 1990. That column was titled, “The Rebirth of Thermal Keratoplasty (TKP)”, and told the story of Dr. Bruce Sands and his company Laser BioTech (which later licensed the technology to Sunrise Technology) trying to use targeted holmium laser energy to shrink collagen fibers, without thermal trauma, to flatten the cornea.

As background to this story, I also wrote about earlier attempts to use microwave energy to do the same thing, by a group that included Ralph Crump of Frigitronics (developer of the Softcon Lens – later licensed to American Optical) and Stuart Trembly of Dartmouth College. They were issued a patent that disclosed the use of microwave energy to shrink collagen tissue.

Nothing came from the microwave effort, and Sunrise Technology’s laser was marketed for a short time but the lack of precision in the shrinkage of collagen and a loss of effect lead to its demise.

The only company to take advantage of precise collagen shrinkage has been Refractec, with its Viewpoint CK conductive keratoplasty technique. This technique uses short pulses of radio-frequency energy introduced into short metal probes inserted into the cornea in a tight pattern for the correction of hyperopia.

Well, apparently there is a new company, founded by David Muller, the former CEO of Summit Technology and the above mentioned Stuart Trembly, called Avedro Inc. that is using microwave technology to successfully change the cornea's shape for correcting vision.

According to a recent filing with the U.S. Securities and Exchange Commission, the firm has raised an additional $10 million of equity venture capital funding to go along with its initial financing of $8 million.

Avedro's technology, called Keraflex, uses focused energy to reshape the front surface of the cornea. Avoiding the creation of a flap in the cornea or the need for the removal of any corneal tissue. Clinical trials will start shortly, followed by product launch in Europe.

As I learn more about this effort, I will report it in this space.



This column was published in the October 1990 issue of Ophthalmology Management.


TECHNOLOGY UPDATE


THE REBIRTH OF THERMAL KERATOPLASTY (TKP)

Irving J. Arons

There is an old adage that says, "What goes around, comes around". And it looks like it will hold true again in the case of trying to change vision by applying heat energy to the cornea.

Over the years, there have been several attempts to change the shape of the cornea without surgery, by acting on the collagen lamellar that makes up the bulk of the stromal layer beneath the epithelium. The earliest attempts that I'm aware of were the application of a radio-frequency heating device to the surface of the cornea -- the Los Alamos Keratoplasty Technique(1) in the late 1970s. There have also been mechanical and chemical/mechanical means tried as well. In the mid 1970s, Charles Neefe of Midland, TX was issued a series of patents that disclosed the use of drugs to soften the collagen, followed by the application of rigid contact lenses to reshape the softened tissue(2). Then of course, there is the application of a series of ever tighter rigid contact lenses to correct high myopia (orthokeratology).

More recently, two newer methods of shrinking collagen have surfaced. The first, discussed at the 1988 AAO meeting in Las Vegas, involves equipment and a technique developed by Dr. Svyatoslov Fyodorov, of the Moscow Research Institute of Eye Microsurgery. A special handpiece is applied to the corneal surface and rapidly heated to 60°C and held at temperature for 0.3 seconds. By applying an RK type pattern to the cornea, Dr. Fydorov claims to obtain changes of 2-4 diopters with his thermocoagulating unit for thermokeratoplasty (TKP). Several US ophthalmologists have been trained in the technique and reportedly, Alcon Labs has obtained a license to develop the instrument(3).

This past July, a Business Week article(4) drew attention to a patent obtained last November by Ralph Crump (formerly President of Frigitronics) and Stuart Trembly)a professor of engineering science at Dartmouth College). The patent discloses the use of microwave energy to shrink collagen tissue in the mid-stroma. This device is reportedly in early stage development, with testing proceeding on removed animal eyes.

The most recent technology disclosure, and perhaps the most interesting, is the use of lasers to selectively shrink targeted collagen sectors in the mid-stroma, by raising the collagen's temperature by about 23°C above ambient with microbursts of energy. According to Dr. Bruce Sand(5), CEO of this yet little known company, Laser BioTech, Beverly Hills, CA, the laser energy is used to cause shrinkage of the collagen fibers to about one third their length, without causing thermal trauma to trigger a wound response and thereby negate the shrinkage. Animal experiments have shown that with a controlled burst of energy, myopia, hyperopia, and astigmatism can be corrected without effecting either the epithelium or endothelium. True intrastromal shrinkage without thermal trauma and subsequent collagen coagulation has been accomplished using bursts of 3-10 millisecond pulses with relaxation intervals of 50-200 milliseconds, from a 2.1 micron holmium-doped pulsed YAG laser. The total energy density is up to 100 joules/sq.cm. According to Dr. Sand, their patent application covering the technique has been allowed and will issue later this summer or by early Fall.

Laser BioTech was incorporated in 1986, and in conjunction with Medical Optics, Inc., a subsidiary of Kaiser Electro-Optics and Kaiser Aerospace and Electronics, has built and tested the prototype design of the solid state laser. The privately held company is currently seeking corporate sponsorship to expand the animal trials and further develop this unique concept into a clinical instrument.

Look out Phoenix Laser, ISL, Summit, Taunton and Visx, there's another company with interesting new technology looking in through the crack in the door!

NOTE: In my July/August column, "Report from ARVO", I also noted that work on laser thermokeratoplasty was being investigated with a Ho:YAG laser by a research group in West Germany, headed by Theo Seiler.


Footnotes:

1. Rowsey et al, "Los Alamos Keratoplasty Techniques", Contact Lens Medical Jnl, Jan/Mar 1980.

2. A series of US Patents issued to Charles Neefe from 1973-1976.

3. "Hyperopic Surgery Kindles Heated Debate", Review of Optometry, January 1989.

4. Developments to Watch, "Clearing up Cloudy Vision -- with Microwaves", Business Week, July 2, 1990.

5. Private correspondence with Dr. Sand, August 1990.

INDEX/SEARCH

INDEX/SEARCH

For your convenience, and because only the last ten posts are shown on the opening page, here is a means for finding all of my posts in an easy-to-use fashion.

Use the Blog Search box in the upper left-hand corner of the header above, enter in "Menu" and click on "search this blog" and menus for all of my 120 or so postings will come up in an easy to search/find method (including short descriptions and live links.)