Assignment #5 (corresponds to Guyton pages 27-36)
Due: 2/6/12
Email to wingardjb@upmc.edu
- Review questions 16-20, 25-26, 36-37, 41, 43, and 45 from the Guyton book.
- A 6 diopter hyperope has 8 diopters of accommodative amplitude. What is the range of accommodation?
- A 10 diopter myope has 5 diopters of accommodation. What is the range of accommodation?
- A spherocylindrical lens has a power of +4 in the 90 degree meridian and +10 in the 180 degree meridian. With respect to the lens, where is the circle of least confusion located?
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A. Transpose +2.00 -1.25 x 75 into Plus cylinder form.
B. Transpose -7.00 +1.75 x 160 into Minus cylinder form.
C. What type of astigmatism would these two prescriptions correct (simple myopic, mixed, etc.)?
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Give the spherical equivalent of the following lenses:
A. +3.00 -4.00 x33
B. -2.00 +4.00 x75
C. -7.50 +0.50 x180
D. Plano +1.50 x90
- Determine the rigid contact lens power for K readings of 44.00 and 46.00, refraction +9.50 +1.50 x113 at a vertex of 15 mm. Fit contact 0.50 diopters steeper than the flat K.
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A. Use the SRK formula (not SRK II) to pick the IOL power for in-the-bag emmetropia for an MA60AC IOL (A constant 119.5), AL of 26 mm, and K readings of 44.50 @90 and 45.50 @180.
B. How would the selected IOL power change if you placed this IOL in the ciliary sulcus (instead of in-the-bag)?
C. How would you adjust the power if you were aiming for a little bit of post-operative myopia?