subject: Experimental Lenses for RLE [print this page] Experimental Lenses for RLE Experimental Lenses for RLE
Refractive Lens Exchange (RLE) is essentially cataract surgery, but is used primarily for refractive purposes. An alternative to LASIK surgery for patients who are presbyopic (farsighted), RLE replaces your eye's clear natural lens with an artificial lens that is hidden behind your iris.
The same refractive intraocular lenses (IOLs) used for cataract surgery can be used for RLE, including accommodating IOLs and multifocal IOLs.
Accommodating IOLs
To date, the only accommodating IOL approved by the Food and Drug Administration (FDA) is the Crystalens. This single-focus accommodating lens works naturally with your eye's muscles to give you the quality of vision that you had in your younger years.
There are several types of experimental accommodating lenses undergoing clinical trials, such as:
Accommodative 1CU (HumanOptics, Erlangen, Germany): In 2000, the 1 CU was implanted for the first time at the University Eye Hospital of Erlangen-Nuremberg University. Since then, more than 200 patients throughout Europe have received the lens and reported satisfactory results, according to Human Optics.
Smartlens (Medennium, Irvine, CA): Currently under development, this IOL utilizes a "SmartMaterial" that will behave similarly to the natural lens and allow your eye to focus from far to near. The mechanism is based on the classic Helmholtz theory for replacing the aged, rigid lens with a full-sized, gel-like flexible lens to restore accommodation.
Sarfarazi accommodative IOL (Bausch and Lomb, Rochester, NY): Now undergoing clinical studies, this single-continuous silicone accommodative lens mimics the action of your natural lens by using the contraction and relaxation of ciliary muscles.
Multifocal IOLs
There are three multifocal IOLs that have been approved by the FDA: ReZoom, ReSTOR, and Tecnis.
New designs of multifocal IOLs that are undergoing clinical studies include various versions of Acri.Tec IOLs, which emphasize different zones for near, intermediate and distance vision. This ultra-thin IOL has a standard edge thickness and is designed so that all the rays meet exactly at one focus. The optic is aspherical, which contributes to the perfect optical performance of this new lens.
Future versions of existing, approved multifocal IOLs may have toric designs (with two different optical powers at right angles) for also correcting astigmatism.
