The natural lens of the eye is flexible and capable of changing shape in young persons.
The lens is held in place within the eye by fibrous strands, or zonules, which attach the outer capsule of the lens to the focusing muscle (called the ciliary muscle) that surrounds the lens.
Accomodating intraocular lenses
A realistic expectation is that you will be less dependent on reading glasses after accommodating IOL surgery, and that you will be able to read and see many things up close better than you could prior to surgery without bifocals or reading glasses.
In some cases, an accommodating IOL may be properly implanted, but the ciliary muscle or the zonules attaching the lens capsule to the muscle may no longer function properly.
As the IOL moves forward during focusing effort, the optic may also flex slightly, adding to the eye's magnifying power for reading.
Candidacy for accommodating IOL surgery is determined using the same criteria used to determine candidacy for either refractive cataract surgery or refractive lens exchange.
It also increases pressure exerted by the vitreous body the clear, gel-like material filling the back of the eyeball, behind the lens capsule.
These two actions allow the accommodating IOL to move slightly forward, increasing the magnifying power of the eye and providing for better reading vision.
If you choose to have an accommodating IOL implanted during cataract surgery, you typically will have to pay the difference between the cost of the accommodating IOL and the amount your insurance plan allows for the cost of a conventional IOL. Currently, only one brand of accommodating IOL is FDA-approved for use in the United States the Crystalens accommodating IOL produced by Bausch & Lomb (Rochester, NY).
However, other brands are currently being clinically tested and may be available soon.
To see clearly up close, the ciliary muscle contracts and the lens becomes more curved.
Because the central optical portion of an accommodating IOLs typically is less flexible than the eye's natural lens, these intraocular lenses must work in a different way.
Instead of changing shape, an accommodative IOL moves slightly forward within the eye in response to focusing effort.