Position of Crystalens is further forward in the eye

when viewing a near object

Position of Crystalens is further back in the eye

when viewing a distant object

The Jules Stein Eye Institute nowoffers patients a mode of vision

correction available at only a handfulof Southern California centers—theaccommodative intraocular lens. SinceNovember 2003, when the Crystalens™(eyeonics, inc., Aliso Viejo, CA) wasapproved by the Food and DrugAdministration (FDA) for use in thiscountry, it has attracted much interestfrom clinicians and patients, reports D.Rex Hamilton, M.D., Assistant Professorof Ophthalmology at the Institute andDirector of the UCLA Laser RefractiveCenter. “It can simultaneously solvetwo problems of aging eyes: cataractand presbyopia. Unlike standard single-

focus lens implants, which correct dis-tance vision only, the Crystalens has aflexible, hinged design allowing move-ment backward and forward within theeye (see illustrations above). For selectpatients, Crystalens restores the mostnatural range of near, intermediate, anddistant focusing ability currently avail-able,” Dr. Hamilton says.

Greater ExpectationsAt present, the best candidates for

Crystalens have some lens yellowing (orother changes requiring cataract surgery)and are hyperopic, but have an other-wise healthy eye: a normal cornea, andno macular degeneration, significant

Jules Stein Eye InstituteU C L A

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September 2004Volume 13, Number 3

Accommodating Change: Intraocular Lenses

Clinical Update

Our web site address ishttp://www.jsei.org

Physician’s Direct Referral Line:

(310) 794-9770

glaucoma, or high astigmatism.Crystalens implantation will notrestore near vision to that of a 20-year old, Dr. Hamilton admits, but formost patients it will provide “practi-cal” vision for tasks such as readinglabels, cellphones, or menus.“Today’s lens model may be some-what limited for the mildly myopicpatient, especially one without muchof a cataract who could simplyremove his or her glasses to read.Future technical refinements will like-ly increase the amount of accommo-dation that can be restored, but fornow it’s important to set expectationsappropriately,” he notes.

Finer Biometry Patient expectations for largely

eyeglass-free vision mean thatCrystalens surgery must rely onpreoperative measurements of opticfeatures that are much moredetailed and precise than standardultrasound provides for the typicalcataract patient. Explains Dr.Hamilton, “The biometrist at theInstitute is incredibly experiencedin immersion A-scan ultrasound aswell as another state-of-the-artdevice called the IOL Master; thesedevices are essential to ensuringthe most accurate measurements ofthe length of the eye. In addition,we use the very latest cornealtopography system, known as theOrbscan, to generate a detailed ele-vation map of the cornea.Processing this data using special-ized software provides us with cal-culations for optimal correctionthrough precision lens selectionand placement of the Crystalenswithin the capsular bag.”

Intensive CareWhile the Crystalens surgery is

essentially as brief and straightfor-ward as typical cataract surgery,

the immediate postoperative peri-od differs in key ways. “The lenstakes several weeks to settle intoperfect position; to some degree,the capsular bag must heal intoplace against the lens before it canbegin to restore focusing power tothe eye. We educate patients notto expect near vision to be perfecton day one. As time goes by,however, near vision typicallyimproves dramatically in theimplanted eye and improves evenfurther once the second eye hasreceived the Crystalens,” Dr.Hamilton notes.

Postoperative care is also criti-cal because the Crystalens sits in avery different position than a nor-mal lens and must be closely mon-itored to ensure that it seats itselfproperly. Therefore, accuracy ofthe lens power selection and lensposition within the eye arechecked the day after Crystalensimplantation in the first eye, andremeasured two weeks later. If noadjustments are needed, the sec-ond eye can be implanted, thenassessed on day one, at week two,and again at one month.

Patient ViewpointDr. Hamilton describes the patient

experience of Crystalens surgery asalso distinctive from other remediesfor those with presbyopia. “ThoughLASIK and contact lenses can be veryeffective for patients who wish toavoid wearing glasses for distanceand reading, these techniques aresomewhat workarounds for the prob-lem of presbyopia. They do notrestore a dynamic focusing ability tothe eye as does the Crystalens, whichtakes advantage of the documentedfact that the ciliary muscle of the eyeis still capable of functioning wellinto one’s 80s. By replacing the aginglens of the eye with the Crystalens,

we can restore some of its dynamicfocusing capability,” he says.

Upcoming AttractionsDr. Hamilton continues to

scrutinize several other designs,some very different, for accom-modating intraocular lenses cur-rently in development or in clini-cal trials abroad. At this time, theyoffer too little near vision correc-tion, or have yet to resolve tech-nical issues related to implanta-tion, healing, and scarring. “Oncewe have more experience withthis technology and know moreabout its benefits and limitationson a large scale, an accommoda-tive lens could potentially besomething every cataract surgeonmight use,” he says.

Medicare currently disallowsCrystalens replacement for anyonewith a documented visually signif-icant cataract, so most patientsnow seen at the Institute forCrystalens replacement are under65 years of age. But Dr. Hamiltonthinks accommodative lenses offerpeople who already need surgeryfor cataract replacement theadded advantage of seeing thingsnear, far, and in between, “thusrestoring function to the eye in away like no other. From that per-spective, accommodating intraoc-ular lenses give us an opportunityto provide a huge benefit to the patient.”

CRYSTALENS REFERENCES: Doane JF. Accommodating intraocular lenses. Curr

Opin Ophthalmol 2004; 15(1):16-21.

Cumming JS, Slade SG, Chayet A. AT-45 Study

Group. Clinical evaluation of the model AT-45 sili-

cone accommodating intraocular lens: results of

feasibility and the initial phase of a Food and Drug

Administration clinical trial. Ophthalmology 2001;

108(11):2005-9.

2 JSEI Clinical Update September 2004

INTRAOCULAR LENSES (continued from page 1)

TreatmentAfter approval of the original retinal surgeon, the exposed scleral

buckle was removed through a nasal peritomy in one piece, recogniz-ing from preoperative MRI that the junction of the buckle ends waslocated temporally (Figure 2 bottom). Guided by the imaging, the leftmedial rectus muscle was recovered and reinserted on an adjustablesuture via a nasal conjunctional approach after scraping of the epithil-ialized bed of the exposed buckle. The right medial rectus muscle wasresected 4 mm, and the lateral rectus muscles recessed 7 - 8 mm. Afterthe second surgery, patient was orthotropic in all gaze positions(Figure 1 bottom).

High Resolution Magnetic Resonance Imaging inTreatment of Severe Exotropia Following ScleralBuckling for Retinal Detachment

33September 2004 JSEI Clinical Update

(continued on page 4)

The following case report was submitted by Joseph L. Demer, M.D., Ph.D., Professor of Ophthalmology in the Pediatric Ophthalmologyand Strabismus Division and Director of the Ocular Motility Laboratory in the Jules Stein Eye Institute.

Case 1A 61-year-old man presented to the Jules Stein Eye Institute with hor-

izontal, binocular diplopia following bilateral scleral buckling per-formed elsewhere for retinal detachments associated with high myopia.He had undergone scleral buckling on the left eye 4 years previously.Another retinal detachment occurred in the right eye 8 months beforepresentation, and was also corrected by scleral buckling. Corrected acu-ity was 20/20 in both eyes. On examination, there was 65 prism dioptersleft exotropia and 15 prism diopters left hypertropia (Figure 1 top). Thescleral buckle was exposed and extruding nasally from left eye. Forcedduction testing demonstrated mild restriction to full adduction of the lefteye, but force generation testing detected no left medial rectus force.High resolution magnetic resonance imaging (MRI) was performedusing high performance surface coils and optical fixation control inmultiple gaze positions. Axial views (Figure 2 top) showed disinsertion ofthe left medial rectus muscle behind a large silicone explant, with theterminal tendon apparently adherent to the connective tissue along theposterior border of the explant. The right medial rectus muscle was nor-mally inserted anterior to its buckle. By repeating the MRI scan in rightand left gaze positions, normal contractile thickening was demonstratedfor both medial rectus muscles in adduction.

DiscussionHigh resolution, multiposi-

tional MRI of the extraocularmuscles can be clinically valuablein guiding the management ofsevere or complex strabismus,particularly when disinserted, lost,or traumatized muscles are sus-pected. Through long-term sup-port of the National Eye Institute,Dr. Demer’s laboratory at theJules Stein Eye Institute hasdeveloped MRI hardware andclinical imaging protocols capableof achieving near microscopicresolution of the extraocular mus-cles and motor nerves. Thesemethods employ standard clinicalMRI scanners, surface coils thatare available in most centers, andmost importantly procedures opti-mized for extraocular muscleimaging. The techniques typicallyemployed for MRI of the brainare not adequate for extraocularmuscle imaging. In order to getMRI images of the quality illus-trated here, the ophthalmologistmust work very closely with theimaging facility.

Good quality orbital MRI inmultiple gaze positions offerstwo clinical insights. First, thecontractility of extraoclular mus-cle bellies can be assessed byobserving the degree of changein muscle size and shape in thedeep orbit during contraction andrelaxation. Contractile changesare easily evident even in mus-cles widely disinserted from theglobe and therefore unable toexert rotational force on the eye.

Figure 1. Clinical photos showing correction of severe exotropia.

Second, multipositional MRI can aidin determination of muscle attach-ment, since attached muscle inser-tions remain in constant spatialrelationship with the globe during

ductions, and disinserted musclesdo not. Reattachment of disinsertedextraocular muscles can have grati-fying clinical results. Even extraoc-ular muscles that have been disin-

serted for many years can functionwell after surgical recovery andreattachment. With modern orbitalimaging and surgical techniques,disinserted extraocular musclesshould no longer be regarded as“lost” when they are no longerinserted on the sclera. Extraocularmuscle imaging consultations forthis purpose can be arrangedthrough the Jules Stein EyeInstitute.

RECENT PUBLICATIONS Demer, JL. A 12 year, prospective study of extraoc-

ular muscle imaging in complex strabismus. J

AAPOS 2003; 6:337-47.

4 JSEI Clinical Update September 2004

CASE REPORT: TREATMENT OF SEVERE EXOTROPIA (continued from page 3)

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Figure 2. (Top) Axial MRI shows disinserted leftmedial rectus (MR) muscle. (Bottom) Coronal MRIrevealed the junction of the buckle ends waslocated temporally.