What Are Hard and Soft Designs of Progressive Lenses?

Changes in vision occur as a natural part of aging, beginning around the age of 40. This change is called presbyopia, or the loss of near vision. Bifocals and trifocals, previously the only available options to compensate for diminishing visual clarity, had visible lines separating the three viewing ranges -- near, intermediate and distance. Progressive lenses, also known as multifocal lenses, eliminate the lines of distinction and gradually blend the different prescription strengths into each other to eliminate distortion and provide a more natural viewing experience.
  1. Placement of Viewing Zones

    • An area extending vertically through the center of the lens is the location for the three visual zones of correction -- near, intermediate and distance. This area is known as the corridor. Accurate placement of the three sections along the corridor assures clarity of vision, ease of transition between the viewing areas and facilitates adjustment to progressive lenses, which can take up to two weeks. Vision is slightly distorted along the peripheral areas of the lens, the bottom, far right and far left. The width and length of the individual viewing zones are different for soft-design lenses and hard-design lenses.

    Soft Design Lenses

    • Soft-design progressive lenses provide clear, uninterrupted vision as you change focus from near to far objects. In the intermediate zone, soft-design lenses provide a wider viewing area and greater depth than hard-design lenses. The intermediate range for soft-design lenses is 18 to 30 inches. This additional width and length make soft-design lenses useful for doing computer work. If you are over age 50 or accustomed to wearing progressive lenses, soft-design lenses may be the best choice for you, according to MasterEyeAssociates.com.

    Hard Design Lenses

    • Hard-design lenses have a shorter corridor, which allows them to fit in smaller frames. They also provide a wider viewing area for near objects within a range of 14 to 18 inches, and slightly clearer and wider distance viewing without distortion. This feature makes hard-design lenses a better choice for people 40 to 48 years of age who require near and distance viewing correction with minimal or no intermediate vision correction.

    Pros and Cons

    • Soft lenses have less peripheral distortion than hard-design lenses. Soft-design lenses are larger because of the longer corridor needed to accommodate natural viewing throughout all ranges of vision. As a result of their greater size, soft-design lenses do not fit in small eyeglass frames. Although hard-design lenses fit into smaller frames, they still provide a large enough close up viewing zone for comfortable reading. The shorter corridor in hard-design lenses does not allow enough space to include a sufficient intermediate zone, which is required to use a computer.

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