How It Works

Facts about accommodation:

- Zonules are the gossamer thin fibers that are the sole connection between the ciliary body and the lens capsule.

- As the ciliary body constricts during accommodation, the zonules loosen.

- Zonules are 1 to 2 microns in diameter 1 (For comparison, red blood cells are about five microns in width.)

- Zonules cannot push

- Zonules can only pull

All proposed accommodating lens designs need to answer this one basic question:

How is force transmitted during accommodation from the loosening zonules to the capsular bag?



1 Bornfeld, Norbert; Spitznas, Manfred; Breipohl, Winrich; Bijvank, Gerhard J. (1974). “Scanning electron microscopy of the zonule of Zinn”. Albrecht von Graefes Archiv für klinische und experimentelle Ophthalmologie. 192 (2): 117–29.

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    When manufactured and molded out of silicone, the ActaLens is formed in its non-planar accommodating configuration with the optic anterior to the haptics.
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    Prior to implantation the ActaLens is restrained into a flattened configuration. The lens is delivered to the surgeon in this primed configuration.
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    Following standard phaco procedure, ActaLens is injected into the capsular bag through a 3 MM corneal incision.
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    Cycloplegia is maintained while the capsule attaches to the flattened IOL.
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    The restraint is released by YAG laser which allows the optic to move forward, recreating the natural tension that exists between the zonules and the lens.Forward movement is limited by this zonular tension, and the lens is maintained in a flattened, distance-focus position.
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    According to Helmholtz, accommodation initates a reduction in zonular tension which allows the optic portion of the ActaLens to move anteriorly. This forward movement increases the focusing power of the eye and contributes to accommodation.
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    Conversely, disaccommodation causes the ciliary body to relax and re-tighten the zonules, which flattens the lens and pulls the optic posteriorly to its disaccommodated position

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