1. | Reflection is when light rays are redirected in a different direction, usually with a loss in amplitude |
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2. | What is refraction based on? |
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3. | As n _____, the speed of light _______. |
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4. | The slower the light passes through a lens, the ____ it gets refracted. |
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5. | A prism will bend light rays towards its ________. |
6. | A prism will shift an image towards its ______. |
7. | The prism diopter is the unite for prisms and it represents: |
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8. | An angle of 1 radian results in an arc with an equal length to the _______. |
9. | 1 radian = |
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10. | 1 prism diopter = ______ radians |
11. | 1 prism diopter = _____ degrees |
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12. | Describe in words what a prism diopter is. |
13. | How much power does a prism have if it is able to displace an image by 5cm at a viewing distance of 0.5m? |
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14. | A 20 pd BU prism will displace an image by what distance at a viewing distance of 5m? In what direction will the imave be displaced? |
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15. | A prism is able to displace an image by 4 degrees. What is the power of the prism? |
16. | What is the name of an instrument that is a tower of mini-prisms that are 1mm thick. |
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17. | Indicate the advantages of a Fresnel Prism. |
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18. | Indicate the disadvantages of Fresnel Prisms |
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19. | Indicate the clinical uses of prisms. |
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20. | One should orient the prism apex away from the deviating eye to place the image where the deviating eye is looking |
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21. | Your patient's right eye is misaligned with his left eye so that the right is higher than left. What is the direction of the prism base that you would prescibe for the right eye? |
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22. | What components are used to specify a prism? |
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23. | The coordinate system for prism is the same as with cylinder axis. |
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24. | Because the eye muscles are yoked, prism placed before one eye affects both eyes |
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25. | The full prism power must be placed on the eye that is deviated |
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26. | If a patient requires 4 BO total. Indicate what possible prisms they can use. |
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27. | Splitting prisms unequally can help to equalize lens thicknesses when lens powers between the 2 eyes are not equal |
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28. | With horizontal prisms, similar bases are _______. With vertical prisms, similar bases are ________. |
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29. | A patient is prescribed horizontal prisms. She is wearing 2 pd BO OD and 2 pd BO OS. what is the total prismatic effect? |
30. | A patient is prescribed horizontal prisms. She is wearing 2 pd BI OD and 3 pd BO OS. what is the total prismatic effect? |
31. | A patient is prescribed vertical prisms. He is wearing 3 pd BU OD and 3 pd BU OS. What is the total prismatic effect? |
32. | A patient is presribed vertical prisms. He is wearing 2 pd BU OD and 2 pd BD OS. What is the total prismatic effect? (2 answers possible) |
33. | How does one deterine the 'reference eye'? |
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34. | How can we ensure that there is no unwanted, induced prismatic effects? |
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35. | For a positive lens, it is essentialy like 2 prisms with their bases facing ____. |
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36. | For a negative lens, it is essentially like 2 prisms with their bases facing ____. |
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37. | Prentice's Rule depends solves for: |
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38. | The amount of prism induced requires knowledge of what factor(s)? |
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39. | How much prism is induced if a +6.50 lens before the right eye is decentered 3mm nasally? |
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40. | A +4.00D lens is ordered for the right eye. The Rx calls for 2 BI prism before the right eye. How should the lens be decentered? |
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41. | A +3.50D lens is decentered 4 mm in and 5 mm down. What is the resultant prismatic effect? |
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42. | If there is no prism prescribed for a patient, the PRP will be at the same location as the OC of the lens |
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43. | The distance between the optical center and the line of sight is the amount of: |
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44. | The major reference point (MRP) of the lens is where the prism amount is unequal to the amount that has been prescribed for the patient. |
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45. | What is the opticla difference between grinding in prisms and prism by decentration? |
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46. | Your optician finds that the PD and the DBOC is off by 10 mm. How much prism is induced and is it ok to dispense them? |
47. | Your patient complains of fatigue from wearing his new glasses. The DBOC is 64mm vs 60 mm as ordered. What is the induced prismatic effect from each eye if the Rx is -2.00-100x180 OU? |
48. | Your patient complains of vertical diplopia. Marking the glasses OCs the OD OC is 4 mm higher than the OS OC. The OS OC is centered over the pt's OS pupil. How much prism is induced and in what direction if the Rxis +4.50-200x180 OU? |
49. | Your patient needs 2 BO OD and 1.5 BO OS. You would rather manipulate the OCs to create the prism. How much decentration is necessary and in what direction to end up with the correct prism if the Rx in both eyes is -5.00 DS? |
50. | What is the different between compounding and cancellation? |
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51. | Your patient is complaning of vertical diplopia through her new glasses. The right OC is 3mm ABOVE her pupil while her left OC is 4mm BELOW her left pupil. Her Rx is -150-050X180 OU. What is the prismatic effect of the OD, OS and OU? |
52. | If a positive lens is shifted temporally what prismatic effect will that produce? |
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53. | If a negative lens is shifted inward what prismatic effect will that induce? |
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54. | If a +3.50 lens is deceneterd 4 mm in and 5mm down in front of the OD, what is the resultatnt prism? Express as vertical and horizontal componentw. |
55. | What factors affect the induced prism due to decentration? |
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56. | When is it apprpropriate to use Prentice's Rule? |
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57. | What is the primsmatic effect of a plo-2.00x180 lens when it is decentered 5mm nasally over the right eye? |
58. | What is the primsmatic effect of a plo-2.00x090 lens when it is decentered upward over the right eye? |
59. | When do we use the Sine-Squared Method? |
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60. | What is the equation to find the power in a oblique meridian? |
61. | What is the cyl power of the Rx -2.00-100X030 at the 180 meridian? |
62. | What is the cyl power in the horizontal meridian (180) of plo+200x030? F= 0 + (sin2(30)) = +0.50 |
63. | What is the cyl power in the vertical meridian (90) of -2.50-200x060? |
64. | How much prism is induced if the Rx is -4.00-1.50x045 if decentered nasally by 5mm over the OD? |
65. | What factors are important for measuring the prism power at the center? |
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66. | How much prism is present in the middle of a lens that has an index of 1.50, diameter of 50mm? The apex is 2mm and the base is 5mm. |
67. | A -6.50 DS polycar lens is fitted into an oval frame with a horizontal diameter of 48mm. The nasal edge thickenss is 4.2 mm and the temporal edge thickness is 5.8mm. What horizontal prismatic effect is found exactly in the center of the lens? |
68. | How much prism is induced if a lens with an Rx of -200-200x060 is decentered 3mm temporal over the OD? |
69. | The DBOC of your new glasses measures 68mm but your PD is 64 mm. How mch prism is induced in each eye and in what direction if your Rx is OD +200-400x060 OS +100-400x045. Assume the PD is equally off OD and OS. F180 = (+200) + (-400)(sin2(60)) = -100 --> (-100)(0.2) = 0.2 BI F90 = (+100) + (-400)(sin2(45)) = -100 --> (-100)(0.2) = 0.2 BI (0.2)+(0.2) = 0.4 BI (remeber that same bases will add in this case) |
70. | Because the add power will always be positive, the power that you measure through the near add will always measure: |
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71. | When neutralizing a pair of glasses you measure +200-075x180. The near add power is +200, the sphere and cyl target lines would read ____ and ____ when viewed through the segment. |
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72. | Indicate the incorrect match. |
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73. | Why do low myopic patients have the hardest time understanding presbyopia? |
74. | You are neutralizing a pair of bifocal glasses and you get -200-100x135 in the distance portion. If the power measured through the add is +0.50-100x135, what is the near add power? |
75. | What type of bifocals have no ledge? |
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76. | There are many different materials available for fused glasses designs. |
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77. | For a fused multifocal design, which area has the higher n? |
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78. | What type of materials are commonly used for One Piece MFs? |
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79. | Cement Seg MFs are cement segments that are glued onto the distance portion of lenses |
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80. | Segment Widtch is measured from: |
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81. | Segment Height is measured from: |
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82. | The Segment Depth is the: |
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83. | The Seg Inset is the distance between the distance OC and the near OC |
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84. | Describe how to measure a patient's seg height. |
85. | Round segments only come in fused form |
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86. | Describe the pros and cons for round segments |
87. | Which widths are available in round segments? |
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88. | In which occupations are round segments useful? |
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89. | What is the most preferred bifocal design due to less distortion? |
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90. | What seg widths do flat top/D segs come in? |
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91. | As the ledge sticks out more for a flat top, the seg narrows |
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92. | Curved top are usually ______ and executives are usually ______. |
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93. | Describe the difference between curved top and Panoptik segments |
94. | How many optical centers do Executive bifocals have? |
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95. | Select the material and available seg widths for Ultex series. |
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96. | What is the height of the intermediate portion for a trifocal lens usually? |
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97. | What was the Datum System used for? |
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98. | How did the Box System update the Datum System? |
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99. | In the Box System, the longest horizontal length is considered the _____ when referring to the frame and the _____ when referring to the lens |
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100. | Another term for the lens size is: |
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101. | The longest vertical height of the frame is called the: |
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102. | Describe how to measure the C. |
103. | C will always be greater than A |
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104. | What do we have to add to our A and B measurements to get the final measure? |
105. | The geometric center is another name for the optical center. |
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106. | The effective diameter is the distance from the geometric center to the furthest pont on the frame. |
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107. | What does DBL stand for? |
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108. | How does one calculate the Frame PD (FPD)? |
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109. | What 3 measurements are used in the Box System? |
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D. |
110. | The larger the lens blank, the thinner the lens will be |
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111. | The goal is to use the smallest lens blank possible that will still fit in the frame |
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112. | The Minimum Blank Size (MBS) equals: |
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C. |
113. | What would the MBS be for a single visin lens that is to be mounted in a frame having the following dimensions: A= 52mm DBL = 18 mm ED = 57 mm PD= 62mm |