Crystalens® is currently the only accommodating intraocular lens (IOL) approved for lens replacement after cataract surgery. The only cure for cataracts is the removal of the natural lens which has become clouded. The lens is then replaced with an artificial lens.
In the past, monofocal intraocular lenses were the primary option to help people who are losing their vision to cataracts. This meant that most people would have acceptable vision for looking at distant objects, but would have to wear reading glasses, bifocals, or trifocals. Now, new intraocular lenses have been invented that allow you to see at multiple distances and often live life free of reading glasses, bifocals, or trifocals.
Most of the new intraocular lenses are known as multifocal lenses. ReZoom™, ReSTOR®, and Tecnis® Multifocal are examples of this type of lens. But Crystalens® is a new option known as an accommodating IOL.
Focusing on objects at different distances is controlled by the cilliary muscle which surrounds the lens. When you focus on distant objects the ciliary muscle relaxes, giving the lens steeper curvature. To see close-up things, the ciliary muscle contracts, making the lens flatter. This is what is known as accommodation.
Crystalens® allows the ciliary muscle to behave as it always has. Relaxing allows the Crystalens® to move slightly backwards, while contraction moves it forward. The effect is similar to changes in lens curvature. Moving the lens changes which light rays are focused precisely on the retina.
Crystalens® is made from solid silicone Biosil, a highly biocompatible material. But the genius of the lens is in its design: it features hinges. When Crystalens® is implanted in the space left after your natural, cloudy lens is removed, it is attached to the ciliary muscle Now the muscle can control the movement of your Crystalens®.
The not-yet-approved intraocular lens Synchrony, which may soon become the second accommodating IOL to be approved by the FDA, also features hinges. However, Verisyse features two lenses, with the ciliary muscle controlling the distance between them.
Although Crystalens® works great for most patients, there are some potential risks associated with its implantation. Most of the risks associated with Crystalens® are similar to those for other intraocular lenses. These include the possibility of infection, hemorrhage, and retinal detachment.
There are some specific risks related to Crystalens®, however. The manufacturer, Bausch & Lomb, reports that it is possible for the Crystalens® to get stuck either in the forward position (giving only good near vision and requiring glasses or contact lenses for far vision) or the backward position (giving only good distance vision and requiring glasses for near vision).
In addition, the manufacturers warn that unlike the natural lens and most intraocular lenses Crystalens® does not absorb any significant amount of ultraviolet light, which may increase the risk of retinal disorders. They recommend the use of protective sunglasses when out in sunlight.
Finally, some patients and doctors have reported that the results from implantation of Crystalens® is less predictable than the results from multifocal IOLs. Some proposed explanations for this include the increased difficulty in placing Crystalens®, interference from the capsule surrounding the lens preventing the free movement of Crystalens®, or interference from portions of the lens that were not completely removed. In some cases, a capsulotomy may correct these complications.
No procedure can be 100% guaranteed to be effective. It is important to talk to an ophthalmologist with extensive experience in the placement of intraocular lenses. Schedule a Crystalens® consultation today to learn whether this or a different intraocular lens is a better option for you following your cataract surgery.