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Refractive Surgery | Oct 2010

Accommodating IOL Designs

In a feature starting on page 53, a panel of anterior segment surgeons from around the world answers a questionnaire on the following lenses.

AKKOMMODATIVE 1CU
HumanOptics AG
(Erlangen, Germany)

This one-piece hydrophilic acrylic IOL features an ultraviolet (UV)-light inhibitor and four haptics that act as elements of fixation. According to the company, these haptics use the focus-shift principle to enhance reading comfort. The Akkommodative 1CU is a foldable monobloc posterior chamber lens, available in 0.50 D steps from 16.00 to 35.00 D. The biconvex design is 9.8 mm in overall diameter, and the optic diameter is 5.5 mm. The IOL is intended for insertion through a small incision (1.8 mm).

Status: The 1CU has the Conformité Européene (CE) Mark and is available in Europe. The lens is not available in the United States.

CRYSTALENS AO
Bausch + Lomb
(Rochester, New York

The AO is the fifth-generation Crystalens, combining Bausch + Lomb's accommodating IOL technology with the company's aberration-free aspheric lens design. Designed to deliver premium vision at all distances, the accommodating features of the lens include a 360º square edge and an enhanced accommodating biconvex optic (5.0 mm). This optic reportedly increases accommodative arching compared with previous Crystalens models. The aspheric aspects of the lens provide better vision quality relative to standard spherical IOLs, according to the company, and more predictable and repeatable refractive outcomes.

Available from 10.00 to 33.00 D in 0.50 D steps, this biconvex lens has a 5.0-mm overall diameter and is made from the company's Biosil material. The overall length is 11.5 mm from 17.00 to 33.00 D and 12.0 mm from 10.00 to 16.75 D.

Status: The Crystalens AO has the CE Mark and is sold in countries monitored by the European Medicines Agency (EMEA). The Crystalens was the first US Food and Drug Administration (FDA)-approved accommodating lens in the US market; the AO design also has FDA approval.

FLUIDVISION
PowerVision, Inc.
(Belmont, California

The preliminary product design of the FluidVision reportedly creates more than 5.00 D of accommodation, according to the company's clinical data. This lens uses hydraulic actuators (ie, fluid movement) to change the shape of the lens, paralleling the Helmholtz theory. As the ciliary muscles constrict and the zonules relax, the FluidVision lens thickens, and when the muscles relax and the zonules tighten, the lens thins.

Status: The FluidVision lens does not have the CE Mark, nor is it FDA-approved. The company has begun clinical trials outside the United States.

NULENS DYNACURVE
NuLens, Ltd.
(Herzliya Pituach, Israel)

Intended to provide more than 10.00 D of accommodative power, the two-piece NuLens DynaCurve generates its power from ciliary muscle responses to the naturally occurring blur stimulus for accommodation. Of the two lens pieces, one is a HEMA plate placed on top of the collapsed capsular bag after cataract removal, and the other is a rigid haptic system with a silicone gel center. The latter piece of the NuLens DynaCurve is held in place on top of the HEMA plate with patented sulcus-fixation haptics. According to company literature, an effective reference plane created by the rigid haptics deforms the silicone gel as capsular diaphragm movement presses the HEMA plate anteriorly. The anterior and posterior pressures displace the silicone forward, mimicking the accommodative effect.

Status: NuLens has started its first human trials, and more than 20 lenses have been implanted in cataract patients. Six-month results are promising, and the company says it is on the path to initiate regulatory processes during 2010.

SMARTIOL
Medennium, Inc.
(Irvine, California)

The SmartIOL fills the entire capsular bag so that the ciliary muscle may resume control of lens-shape alteration, according to company literature. The IOL is a hydrophobic acrylic material with customizable optical specifications such as power and anterior and posterior curvatures. Unique thermoplastic properties allow the lens to be reconfigured into a thin rod. After implantation through a phaco incision, the SmartIOL warms to body temperature and transforms into its originally designed configuration. The material modulus is similar to that of the natural lens, reportedly allowing the natural accommodative system to alter its shape and power.

Status: Development of the lens has been completed and the company awaits funding for clinical trials.

SYNCHRONY
Abbott Medical Optics Inc.
(Santa Ana, California)

This one-piece, dual-optic accommodating IOL features two optics that are connected by a spring-like haptic design. The springs link a 5.5-mm high power anterior optic and a 6.0-mm negative power posterior optic; according to the company, the spring action is designed to allow the front optic to move forward, changing the eye's focus from near to far. To maintain emmetropia, this combination of positive- and negativepowered optics is customized for each patient. The entire system is preloaded in an injector ready for use.

Status: The Synchrony has the CE Mark, and Abbott Medical Optics has completed premarket approval submission to the FDA.

TEK-CLEAR
Tekia, Inc.
(Irvine, California)

The lens haptic-optic design of the Tek-Clear features a bending beam to optimize IOL movement anteriorly and posteriorly as the ciliary muscle contracts and relaxes. According to the company, this design takes advantage of the natural accommodative process. The 360° full-bag haptic design incorporates a precision square edge, creating flexibility for the capsular bag and responsiveness to the natural accommodative process. The lens is made of a hydrophilic acrylic material and has a 5.5-mm square-edged optic. Available from 17.00 to 30.00 D in 0.50 D steps, the Tek-Clear has customizable haptic sizes from 10.0 to 11.0 mm overall legth, in 0.2-mm steps. It can be implanted through a 2.8-mm incision.

Status: The Tek-Clear received the CE Mark in 2006 and is currently available in Europe, Latin America, and Asia.

TETRAFLEX ACTIVE LIFE STYLE
Lenstec
(St. Petersburg, Florida)

The Tetraflex Active Life Style IOL, with deformable optic, is intended to provide enhanced spectacle independence for cataract patients, according to the company. The deformable optic induces higher-order aberrations during near fixation and demonstrates enhanced spectacle independence, according to the company. The haptic design of the Tetraflex is contoured with 5° anterior angulation to optimize the equiconvex optic for near and far vision. During accommodating, as vitreous is displaced and the involuntary mechanism of convergence demands the extraocular muscles to apply additional forces on the globe, the capsular bag- IOL complex moves and the vaulted anterior optic deforms. During IOL implantation, a tab on the periphery of the acrylic optic identifies that the correct side faces up. The 5.75-mm optic reportedly reduces the risk of halos and glare, and the square-edge design reduces posterior capsular opacification. The overall diameter of the IOL, which is available in 1.00 D steps from 31.00 to 36.00 D and 0.50 D steps from 5.00 to 18.00 and from 25.00 to 30.00 D, is 11.50 mm. The lens is also available in 0.20 D steps from 18.00 to 25.00 D.

Status: The Tetraflex received the CE Mark in 2004 and is commercially sold in Europe. The lens is also sold in China, Australia, Taiwan, Canada, and countries in the Middle East and Eastern Europe. The Tetraflex FDA clinical trial has been truncated, and the company anticipates approval in late 2010.

Editor's Note: Information gathered from company sources

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