Worksheet 6:

Cylinders, compound lenses, characteristics of sphero-cylindrical lenses

  1. Define: spherical surface, cylindrical surface, toric surface.


  2. Define: lens meridian. What are the lowest and highest meridians (or axis) that we deal with for lens power?

    3. Optical cross

    What are the power/major meridian combinations for the following Rx's:
    (For example, the Rx +1.00 -1.00 x 180 is
    at , and at ) [These are the power/meridian combinations that you would put on the two legs of the optical cross.]

  3. -2.50 -1.50 x 045

    4. at , and at
  4. +2.50 -1.50 x 145

    5. at , and at
  5. +2.50 +1.50 x 020

    6. at , and at
  6. +2.50 -3.50 x 175

    7. at , and at
  7. pl -2.50 x 100

    8. at , and at

    For the rest of this worksheet I expect the answers to follow the rules on page (51, 65), so, if you have not gotten that far yet, go ahead and review those rules.

    Remove from the optical cross in minus cylinder form:







    11. Remove from the optical cross in plus cylinder form:








    14. Flat transposition



    Flat transpose:

  14. +1.50 -0.50 x 180


  15. +2.50 +0.50 x 080


  16. -5.75 -0.50 x 095


  17. -0.50 +0.75 x 005


  18. pl +0.50 x 132


  19. +1.50 -1.50 x 079




    20. Prescription Notation



    Rewrite using correct Rx notation: (Do not transpose. Just rewrite.)

  20. +1.50 -.50 x 180


  21. 3.50 -0.50 x 110


  22. +1.00 -1.50 x 280


  23. -1.55 +0.55 x 80


  24. +1.50 -0.00 x 180


  25. Last, but not least, what type of motion does a cylindrical lens show?

I guess by now you know what to do here!

Close the window (click the little x in the upper right-hand corner) if you came here directly from the assignment page.


Textbooks:
Brooks & Borish, Systems for Ophthalmic Dispensing, 2nd Ed, Butterworth-Heinemann, 1996
Stoner, Optical Formulas Tutorial, Butterworth-Heinemann, 1997

Copyright 1998 - 2001, Ellen Stoner, MALS, ABOM, NCLC
Registered students may print one copy for study purposes.