Approved and investigational accommodation IOLs

Saturday, October 17th, 2009 at 7:14 pm Post in Eye Diseases

As we know, some people above 40 can not see clearly at multiple distances, which is caused by the lens’ natural aging and becoming rigid to move smoothly. Among all of the IOLs, accommodation IOL such as the Crystalens has a special design to treat the described presbyopia. An accommodation IOL provides sharp vision by shifting its position with the action of eye muscle and movement, rather than by simply replacing the natural lens. Accommodation IOLs belong to presbyopia-correcting IOLs, so that patients can get multiple distance vision from them.

Firstly approved in 2003, the Crystalens is the only IOL that uses accommodation technology. Bausch & Lomb now is marketing several versions of Crystalens. The newest version claims that it has better near vision and lower side effects.

Among the four types of presbyopia-correcting IOLs, Crystalens IOL is unlike the other three types, which are called multifocal IOLs. Multifocal IOLs perform just like multifocal lenses that the patient should look through an appropriate zone to get certain distance vision. However, IOLs are much smaller than contact lenses, so that these divided zones on IOL are too small to provide clear single vision. Using accommodation, Crystalens can always maintain one focusing zone for any distance vision. A disadvantage of Crystalens IOL is that it provides a narrowed range of focus.

Patients should be aware that neither monovision IOLs nor presbyopia-correcting IOLs can provide perfect vision. Even standard monofocal IOLs may bring night glare and halos. This situation is also true for Crystalens IOLs, which suit people with both presbyopia and cataract. In addition to common complications, Crystalens is reported to bring potential astigmatism and posterior capsule clouding.

Besides Crystalens, there are several types of accommodation IOLs that are still under tests. Approved in Europe, the Synchrony IOL is undergoing clinical trials in US. Synchrony has been proved to bring fewer visual distortion and better intermediate distance vision than ReSTOR. Another type is Tetraflex, which has a square-edged, acrylic optic.