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by Faith A. Hayden EyeWorld Staff Writer

Electronic IOLs: The future ofcataract surgery

Introducing the ELENZASapphire AutoFocal IOL, the world’s first implantable lens with artificial intelligence

Imagine offering a cataract pa-tient an IOL powered by itsown power cell and computerchip embedded inside. It’srechargeable and fully pro-

grammable, allowing the physicianto tweak its optical power as the pa-tient’s visual needs change. It’s anIOL that won’t just mimic naturalhuman accommodation, it’s de-signed to surpass it. This isn’t somelofty overpromise by a science fic-tion-obsessed surgeon; this is the fu-ture of IOL technology. And it’sstanding on our doorstep.

Rudy Mazzocchi is chief execu-tive officer of ELENZA (Roanoke,Va.), the developer of the IOL withthe same name. His voice elevateswith excitement when speaking ofthe IOL, calling it the type of inno-

vation that “comes along once in alifetime.”

“This will probably be thebiggest thing I’ll ever do,” he said.“It’s big not only for the ophthal-mology industry, but also representsa pioneering step in the develop-ment of active, programmablehuman implants.”

ELENZA combines nanotechnol-ogy, artificial intelligence (neuralnetworks-based memory), and ad-vanced electronics to seamlessly aut-ofocus an optic from far to nearwithout movement. Therefore, thelens doesn’t have to rely on precisecontact with ciliary muscles to moveand accommodate properly.

“You’ve seen windows whereyou flip a switch and it polarizes theglass and turns it dark. This is a simi-lar concept,” said Mr. Mazzocchi.“We’re changing the molecular con-figuration of the liquid crystal toalter the optical power of the lens.”

The IOL builds upon an existingtechnology from PixelOptics(Roanoke, Va.), which created theworld’s first electronically focusingprescription eyewear.

“Three or 4 years ago, I wouldhave described this as science fic-tion,” said Richard L. Lindstrom,M.D., founder and attending sur-geon, Minnesota Eye Consultants, aswell as a member of ELENZA’s boardof directors. “I am also involvedwith PixelOptics and thought thiswas science fiction even for glasses.Once that was achieved, the ques-tion became could [the technology]

be made small enough to be dupli-cated in an IOL? It turns out that itcan be duplicated and is being dupli-cated.”

ELENZA is an extraordinarilycomplicated system unlike anythingophthalmology has seen, relying onour individual pupillary response toautomatically trigger accommoda-tion between far and near.

“It’s been proven that the pupilresponds to accommodation by get-ting smaller,” Dr. Lindstrom ex-plained. “The IOL includes sensorsthat detect very small changes inpupil size. The pupillary response toaccommodation is different from thepupillary response to light in regardto amplitude and how rapidly it oc-curs in response to accommodation.”

The microscopic rechargeablelithium-ion battery poweringELENZA didn’t even exist at the be-ginning of the project, said AndrewMaxwell, M.D., Ph.D., chairman ofELENZA’s medical advisory board.Similar batteries have been used incochlear implants, but the batteriesELENZA uses are the smallest cur-rently known to man. Although Dr.Maxwell estimates the battery itselfwill have a 50-year cycle-life, it re-quires recharging every 3-4 days.

The company is conducting de-mographic studies with select pa-tient populations to create an ideal,noninvasive charging process. Themost promising idea is to charge theIOL while the patient sleeps, build-ing a system into a pillow or an eyemask.

As anyone with a computerknows, though, electronics fail. Batteries can clunk out. So whathappens to the IOL and, more im-portantly, the patient’s vision, ifsomething goes awry?

“The fail-safe system is the IOLfalling back to having only optimaldistance vision … defaulting to amonofocal IOL,” Dr. Maxwell said.“The patient goes back to needingreading glasses.”

ELENZA also has a back-up planfor the absentminded patient whomay forget the charger while on anextended vacation: a hibernationmode. If not recharged, the IOL de-faults to a monofocal lens and canbe rebooted up to 9 months later.

Furthermore, the lens is fullyprogrammable and customizable, al-lowing the physician to remotely ad-just the sensitivity and magnitude ofthe switching point of the addpower in the IOL by up to three-quarters of a diopter, based on theparticular needs of the patient.

“This is the most sophisticatedcomputer chip and algorithm everused in an implantable medical de-vice,” Mr. Mazzocchi said. “Withinthe first 300 seconds, this IOL isgoing to learn the specific pupil dy-namics of that patient and cus-tomize its own internal algorithm.As the patient’s needs change withtime, the physician during a visitcan reboot that algorithm and alterits program remotely and noninva-sively. It’s a patient-specific, adap-tive, programmable IOL.”

February 2011IOLs February 2012

Far vision—pupil dilation Near vision—pupil constriction Source: Eyemaginations/ELENZA

AT A GLANCE

• ELENZA is the world’s first IOL with artificial intelligence

• It uses advanced electronics toseamlessly autofocus an optic fromfar to near without movement

• The lens is fully programmable andcustomizable after implantation

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Lingering questionsEven with all of ELENZA’s promises,there are remaining safety and tech-nological issues the company mustovercome before the lens is ready forprime time. For example, what hap-pens to the electronic components ifthe lens is hit with a YAG laser? Areany of the materials toxic? What ifthere’s leakage?

“These sapphire-coated batteriesare sealed and encased in 24-caratgold,” Mr. Mazzocchi said. “We’vetested and proven the integrity ofthis casing and sealed the batteryand all the electronics in a thin glasswafer that’s hermetically sealed andthen encapsulated into a conven-tional monofocal IOL.”

“At this point, knowing whatthe chemists and engineers knowabout the [lens] material, we don’tthink [toxicity] will be a problem,but you never know until you testit,” Dr. Maxwell said.

Another concern is how to im-plant the lens through a conven-tional small incision withoutinducing astigmatism.

“We have a lens design that willfold and still maintain the integrityof all the internal electronic compo-nents,” Dr. Maxwell said. “We alsohave designed an injecting systemthat the IOL will fit into so it will gointo the small incision without anytrauma.”

Look for it in 2018ELENZA is taking all of 2012 toknock out these concerns and othersone-by-one and is not far from de-veloping a finished, clinical-gradeproduct. The hope is for in-manstudies beginning in Europe early in2013.

“ELENZA expects to obtain a CE mark in early 2014,” Dr. Lind-strom said. “FDA approval couldtake 4-5 years after the first implantin man,” he said, “bringing the lensto U.S. soil around 2018.”

“ELENZA is a very exciting project for me right now,” Dr. Lindstrom said. “While there are al-ways surprises along the way, we arepretty confident we can make thiswork.”

Although the IOL is years fromU.S. commercialization, Mr. Mazzocchi and Dr. Maxwell don’tbelieve physicians and patients willbe skittish about implanting a com-

puter chip and battery in the eye. “My philosophy is pretty sim-

ple,” said Mr. Mazzocchi. “As long asthis lens feels and looks like a con-ventional IOL and you can use thesame insertion procedure, we antici-

pate no major adoption issue.”“There will be a group that will

want the new technology immedi-ately and a group that will be moreconservative,” Dr. Maxwell said.

“Ophthalmology, in general, hasbeen a specialty that’s embraced newand advanced technology, especiallywith achieving our Holy Grail with-

February 2011February 2012 IOLs

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by Michelle Dalton EyeWorld Contributing Editor

Determining your surgically induced astigmatism

Experts weigh in on how to define, calculate,and minimize SIA

Inducing some astigmatism isto be expected during cataractsurgery, but with typicalcataract incisions becomingsmaller and smaller, there may

be a time when the discussion ismoot. Until then, how surgically in-duced astigmatism (SIA) is causedand how to minimize it remains rel-evant. The increased use of toricIOLs has thrust the entire issue ofSIA back into the limelight, expertssay.

The moment a keratome passesthrough the cornea, “the astigmaticcharacteristics of that cornea are dif-ferent,” said Warren Hill, M.D., EastValley Ophthalmology, Mesa, Ariz.“We’re treating the post-op astigma-tism by doing our best to predict it.”

Jack Holladay, M.D., clinicalprofessor, Baylor College of Medi-cine (BCM), Houston, said using refraction instead of post-op ker-atometry “can’t be done because thecrystalline lens could contribute tothe pre-op astigmatism.” Post-op Ks,however, “are the only measure-ments that tell you what you’vedone to change the cornea.”

Operating temporally or superi-orly “will give you very different re-sults,” said Douglas D. Koch, M.D.,professor and the Allen, Mosbacher,

and Law Chair in ophthalmology,Cullen Eye Institute, BCM, as willscleral vs. corneal incisions.

“Scleral incisions are going to bemore stable, but certainly very fewof us do them. It’s why using smallerincisions is so beneficial to minimizeSIA,” he said.

What is SIA?SIA is influenced by the incision’s“size, location, corneal radius andcorneal thickness, corneal rigidity,and the folded diameter of the lensas it passes through the eye,” Dr. Hillsaid. A 24 D lens inserted through a2.2 mm incision “will exert a differ-ent influence on the incision than a10 D lens,” he said. “Larger incisionswill induce more astigmatism thansmaller ones.”

SIA “is not consistent. Eyes willalways heal differently from eachother,” and that also affects SIA, said Guy Kezirian, M.D., founder, SurgiVision Consultants Inc., Scottsdale, Ariz., an ophthalmic consulting firm.

Corneal astigmatism differsfrom refractive astigmatism, and the“only way” to determine the SIA is“by running cross cylinder solu-tion—what you have pre-op andwhat you have post-op and the vec-tor difference between the two tellsyou what your SIA is,” Dr. Holladaysaid, adding the incisional lengthand incision location will be the twokey determinants of SIA.

“You’ll have more of an effect at90 degrees than at 180,” he said.

Moving incisions to be on-axisinstead of fixed would help alleviatethe majority of the issue, Dr.Kezirian said.

Operating on the steep axis“will always cause flattening, whichwill always reduce the amount ofastigmatism a person has,” Dr. Holladay said. “You get a bigger ef-fect vertically than horizontally, butyou’d still be reducing the astigma-tism if on the steep axis.”

Dr. Kezirian urges surgeons toadapt incision location to be on axis“because when you have to do a vec-tor addition, you need to know boththe amount and the placement ofthe astigmatism to add it to the pa-tient’s corneal astigmatism to de-velop a solution.”

Calculating your own SIAIn the post-LASIK patient, “we can’tfigure out the true corneal power soit’s next to impossible to determinethe exact IOL power to place,” saidRobert Brass, M.D., founder, BrassEye Center, Latham, N.Y. Using atoric IOL can help address some of

February 2011IOLs February 2012

About 37% of cataract incisions had a small Descemet’s detachment like this one post-op

Source: Douglas D. Koch, M.D., and Li Wang, M.D.

According to Dr. Kezirian: “Distribution of the Standard Deviations (SD) of the change inkeratometric absolute cylinder amounts, by surgeon. Data are from the SurgiVisionDataLink IOL Edition software. The graph is based on data from 2,264 eyes from 55 surgeons who had entered 20 eyes or more having both pre-operative and 3-monthpost-operative keratometry values. The data set excludes eyes that had LRIs or priorsurgery. The distribution plots the SD of the absolute change in keratometry cylinderamounts for each surgeon. One SD includes approximately 67% of eyes.

“Only 6% of surgeons have SIA values with a standard deviation of 0.1 D or less,and only 37% of surgeons have induced SIA values with standard deviations of 0.30 Dor less. The large variation in the induced astigmatism amounts may undermine thevalue of toric calculators, and speak toward the need for making surgical incisions on-axis or 90 degrees away from the pre-operative cylinder axis location.”

Source: Guy Kezirian, M.D.

AT A GLANCE

• SIA can be calculated by subtract-ing the pre-op K from the predictedpost-op K

• Moving incisions to be on axis instead of fixed will reduce SIA

• Larger incision sizes create moreSIA than smaller incisions

• Lower power IOLs create less SIAthan higher power IOLs

out any particular complications.We’ve learned to be more acceptingof advanced technology.” EW

Editors’ note: Drs. Lindstrom andMaxwell are medical consultants for

ELENZA. Mr. Mazzocchi has financialinterests with ELENZA.

Contact informationLindstrom: rllindstrom@mneye.comMaxwell: amaxwellmd@gmail.comMazzocchi: rudy@elenza.com

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