Alcon SEE BRILLIANTLY Refractive and Diffractive Principles in Presbyopia-Correcting IOLs is a user manual that discusses the evolution of multifocal optics utilized in intraocular lenses (IOLs). The manual explains that multifocal IOLs incorporate multiple powers within the same lens, enabling different focal points at different distances. The main distinction between the different optical approaches is the out-of-focus light in diffractive multifocal lenses being spread out uniformly, whereas zonal refractive multifocal lenses concentrate the out-of-focus light into rings.
The Human Eye
The human eye is a dynamic system, enabling good vision under a wide range of conditions. However, the aging process causes the magnitude of accommodation to progressively decrease, leading to presbyopia. This paper will discuss refractive and diffractive principles in presbyopia-correcting IOLs.
Multifocal IOLs
Alcon’s multifocal IOLs incorporate multiple powers within the same lens, enabling different focal points at different distances. The role of the visual-neural system is to filter out or ignore the blurred component and enhance the sharp component, providing acceptable vision for the distinct distances.
Refractive Multifocal IOLs
Refractive multifocal IOLs employ refractive principles to create multiple powers. These early lenses are known as zonal refractive lenses, which had distinct regions or annular zones that refracted light into different foci.
Diffractive Multifocal IOLs
Diffractive multifocal lenses use diffraction and interference to create their multifocality. These lenses take advantage of the wave nature of light, using constructive and destructive interference to create their multifocality.
Manual:
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