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Basic Optical Principles part 3

  1. When the optical centers of a pair of plus lenses are positioned narrower than the PD, it produces prism base __
    in
  2. When the optical centers of a pair of minus lenses are positioned narrower than the PD, it produces prism base __
    out
  3. When a patient looks through a plus lens above the optical center, it produces base __
    down
  4. When a patient looks through a minus lens below the optical center, it produces base __
    down
  5. How much prism is induced 5 mm away from the optical center of a +2.00 diopter lens?
    (5x2)/10 = 1.0 Δ
  6. How much prism is induced 10 mm away from the optical center of a -0.25 diopter lens?
    (10x0.25)/10 = 0.25 Δ
  7. How much prism is induced 2 mm away from the optical center of a +16.00 diopter lens?
    (2x16)/10 = 3.2 Δ
  8. In verifying a pair of spectacles which have been returned from the lab, you notice that the optical centers are positioned 61 mm apart. The work order indicates the patient's PD measures 64 mm and the Rx calls for -3.00 sph in each eye. How much total prism is induced & in which direction is the base?
    • OD: (3x1.5)/10 = 0.45 Δ
    • OS: (3x1.5)/10 = 0.45 Δ

    Minus lenses are positioned narrower than the PD

    total = 0.9 Δ base out
  9. A patient's Rx calls for OD: +4.75. OS: +2.50. The optical centers of the spectacles are found to be positioned 4 mm too wide. How much total prism is induced & in which direction is the base?
    • OD: (4.75x2)/10 = 0.95 Δ
    • OS: (2.50x2)/10 = 0.50 Δ

    Plus lenses are positioned wider than the PD

    total = 1.45 Δ base out
Author
sophathida
ID
337651
Card Set
Basic Optical Principles part 3
Description
ABO part 2
Updated

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