| And trifocal contact lenses are placed a little bit higher in such a way that the area for intermediate zone is on the pupil of the eye. |
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| A bifocal lens corrects both far and near vision, while a trifocal also has an intermediate zone. |
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| In some occupations an intermediate distance is also required, and a third segment can be added, forming a trifocal lens. |
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| Another nonclassical optical system is the bifocal or trifocal spectacle lens. |
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| One analysis reports that neck pain experienced by middle-aged patients often coincides with their first prescription for bifocal or trifocal glasses. |
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| Do you offer prism and trifocal correction? |
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| If you've always worn glasses and you'd prefer to continue doing so, you can learn about bifocal and trifocal lenses and their attributes at All About Vision, a consumer guide to eye care and vision correction. |
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| They are replacing either bifocal and trifocal lenses as in the UK and the Nordic countries or unifocal close-vision lenses, which is the case in Austria, Germany, Belgium, Italy and Spain. |
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| In Europe and Japan, where single vision and progressive lenses are used to correct presbyopia, bifocal and trifocal lenses have virtually disappeared from the market. |
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| However, sales of bifocal and trifocal lenses are declining as they are gradually being replaced by progressive lenses, whose share of the total market has increased by 15 points in the past ten years. |
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| Like bifocal, trifocal, or progressive addition spectacles, multifocal contact lenses have separate powers for distance and near vision in each lens. |
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