The lens in the human eye can be removed for cataract surgery or for the correction of severe nearsightedness. When the lens is removed, it is generally replaced with a lens implant. For the past several years, the human lens was replaced with an implant that left the patient needing reading glasses. Today, there are five different options available for multifocal lens implants which allow the patient to see most things at distance and near with minimal dependence on glasses.
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Differences in Design Basics
According to Review of Optometry, there are two basic categories of multifocal lens implants. One category uses diffractive optics, or concentric zones of distance vision and near vision throughout the lens implant; the other uses a flexible attachment for the lens implant, known as a haptic, that allows the lens to focus on distant and near objects through relaxation and contraction of the focusing muscle in the eye.
Diffractive Optics Designs
Review of Optometry outlines the technical information concerning the diffractive multifocal lens implants. The AcrySoft Restor, Array, ReZoom, and Tecnis multifical lens implants represent the newest available technology in the diffractive optics category. They are what is currently being used on the market in this category. The data that Review of Optometry presented showed that 87 per cent of patients with the Tecnis multifocal lens implant did not require glasses. The AcrySoft Restor lens implant was a close second with 81 per cent of patients with that design remaining free of glasses. The ReZoom and Array lenses did not perform as well in that study. They had only 53.3 and 43.7 per cent of their patients, respectively, remaining free from glasses following the surgery. Of the diffractive optics category, the Tecnis and Acrysoft ReStor designs performed the best.
Adjustable Focus Design
The Crystalens HD is a new design of adjustable focus design that is an improvement on the original Crystalens design. The Crystalens HD is the most commonly used adjustable focus design. According to Review of Optometry, these lenses tend to provide great distance vision, but they do can make it difficult to read fine print at a comfortable reading distance. These designs are best used for someone who must have crystal clear distance vision. They will be able to read at near distances better than someone with a single vision lens implant, but they will still require reading glasses for fine print.
A multifocal lens implant is a great way to eliminate the need for glasses, whether they are distance glasses, reading glasses, or bifocals. The diffractive optics designs tend to cause a small amount of distance vision blur, most commonly described as shadow or ghost images. These usually disappear over time due to sensory adaptation. The diffractive optics designs, such as the Tecnis or AcrySoft Restor, have the best record of keeping patients completely glasses free. Always be sure to discuss these types of things at length with an optometrist or ophthalmologist prior to making a final decision.
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