What is a non-diffractive IOL?
What is a non-diffractive IOL?
Alcon’s proprietary non-diffractive technology uses all available light to create a continuous, extended range of vision. Other diffractive multifocal lenses split the wavefront into multiple separate focal points. The X-Wave technology offers protection against damaging UV rays and filters blue light rays.
What is refractive and diffractive?
Refraction is the change in direction of waves that occurs when waves travel from one medium to another. Diffraction is the bending of waves around obstacles and openings. The amount of diffraction increases with increasing wavelength.
Is a Fresnel lens diffractive?
A Fresnel lens is the diffractive equivalent of a refractive lens.
How does the diffractive nature of bifocal IOLs work?
Bifocal IOLs function by utilizing the diffractive nature of light. As a reminder, when different light waves propagate and coincide at one location, they interfere. This interference may be destructive or constructive (or a partial variation of either), and is a function of the optical path lengths of the individual light waves.
Can a refractive IOL be used for near vision?
Refractive, monofocal IOLs provide patients with corrected vision for either distance vision or near vision. The issue with this design, however, is the inability to correct for both simultaneously. For this reason, modern IOL designs have provided an alternative approach: multifocal IOLs.
How does the extended foci effect the IOL?
While still a diffractive optic, the extended foci allows for nearly all light to be transmitted through the IOL, with the reduction of chromatic aberrations. Both multifocal and EDOF lenses have been shown to increase levels of spectacle independence, however both lens types may be associated with unwanted photic phenomena such as glare and halos.
Which is the first FDA approved IOL lens?
As of July 15th 2016, the TECNIS Symfony IOL (Abbott Medical Optics, Inc. of Santa Ana, California) is the first FDA approved lens of its class. The IOL has a biconvex wavefront-designed anterior aspheric surface and a posterior achromatic diffractive surface with an echelette design (Figure 1).