Designing half-eye binocular spectacle magnifiers.
The process of designing half-eye frames with a smaller than usual eye size and narrower distance between lenses (DBL) in order to produce additional base-in prism effect is described. This method enhances binocular function while the spectacle magnifier is used. The design also provides a lighter, thinner, and cosmetically more acceptable optical aid. Binocular half-eye spectacle magnifiers are useful optical aids, especially for patients with binocular vision, because they are produced in strong powers with strong prism effects incorporated in the lenses. The magnifiers range in power from +6.00 D [symbol: see text] 8 delta base-in to +14.00 D [symbol: see text] 18 delta base-in for vision ranging from 20/60 (6/18) to 20/320 (6/96). Binocular half-eye spectacle magnifiers are recommended for prolonged reading because the strong base-in prism effect relieves the convergence effort, also providing a large field of vision with both hands free.
Fonda
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Saint Barnabas Low Vision Center, West Orange, New Jersey.
D004867:Equipment Design; D005139:Eyeglasses; D006801:Humans; D055095:Optics and Photonics; D015348:Vision, Binocular; D014794:Visual Fields