NCLE exam prep
1. -1.50 -1.50 x 180 - ANS-what is -3.00 +1.50 x 90 in minus cylinder form?
2. -1.75 -1.25 x 180 - ANS-consider the following information and determine the lens power
the lens power to be ordered
3. RX -3.00 +1.25 x 90
4. diagnostic lens -3.00 -1.25 x 170
5. lens does not rotate
6. -2.50 D - ANS-if a GP lens is fit 1.00 D flatter than flat K and the RX is
7. -3.50 -0.25 x 180, what would be the power of the lens?
8. -3.00 -1.25 x 05 - ANS-consider the following information and determine the lens power
to be ordered
9. RX: -3.00 -1.25 x 180
10. diagnostic lens -3.00 -1.25 x 170
11. lens rotates 5 degrees to the viewer's left
12. -3.00 -1.25 x 10 - ANS-consider the following information and determine the lens power
to be ordered
13. RX: -3.00 -1.25 x 180
14. diagnostic lens -3.00 -1.25 x 180
15. lens rotates 10 degrees to the viewer's left
16. -3.00 -1.25 x 170 - ANS-consider the following information and determine the lens power
to be ordered.
17. RX: -3.00 -1.25 x 180
18. diagnostic lens -3.00 -1.25 x 170
19. lens rotates 10 degrees to the viewer's right
20. -3.00 D - ANS-RX -2.50 +0.25 x 90
21. vertex distance = 12 mm
22. if a contact lens is to be fit 0.75 diopters steeper than the flattest corneal meridian, what
would the power be? assume all the astigmatism is in the cornea
23. -3.00 D - ANS-RX -4.00 + 1.00 x 90
24. K: 42.50 @ 180/ 43.50 @ 90
25. a rigid contact lens fit " on K " would require the following power:
26. -3.00 D - ANS-what is the spherical equivalent of the RX -2.75 -0.50 x 180
27. -3.25 D - ANS-if a GP lens is fit 0.50 D steeper than flat K and the RX is
28. -2.75 -0.50 x 180, what would be the power of the lens?
29. -3.50 D - ANS-RX -3.00 -0.50 x 90
30. vertex distance = 11 mm
31. what is the power of a rigid contact lens fit 0.50 D steeper than the flattest corneal
meridian? assume all the astigmatism is in the cornea
32. -3.50 D - ANS-what is the spherical equivalent of the RX -3.75 +0.50 x 90
,33. -3.75` - ANS-your patient is wearing a rigid contact lens with a base curve of 42.50 and
power of -3.25 D. the doctor over refracts -0.75 over this lens. if the final lens to be
ordered will have a base curve of 42.25, what will its power have to be?
34. -4.00 D - ANS-a -3.50 D lens with a base curve of 44.50 provides excellent visual acuity.
if the CPC were changed to 45.00 D what power would be needed?
35. -5.00 D - ANS-what is the spherical equivalent of the RX -5.00 -0.50 x 180
36. -9.00 D - ANS-a spectacle lens is prescribed at -10.00 D provided that the lens is fit at a
vertex distance of 10 mm. a rigid contact lens fit " on K " for this patient would require a
power of:
37. + 14.00 D - ANS-RX + 11.00 + 1.00 x 20
38. vertex distance= 12 mm
39. what would be the power of a rigid contact lens fit " on K? "
40. +/- 0.02 RGP
41. SOFT HYDROGEL +/- 0.03 - ANS-ANSI for center thickness mm
42. +/- 0.05 mm - ANS-the BC of a RGP lens must be verified to be within _______ of that
specified
43. +/- 0.12 RGP
44. SOFT HYDROGEL +/- 0.25 - ANS-ANSI for power 0.00 D to 5.00 D
45. +/- 0.18 RGP
46. SOFT HYDROGEL +/- 0.25 - ANS-ANSI for power 5.12 D to 10.00 D
47. +/- 0.25 - ANS-ANSI for cylinder 0.00 D 2.00 D
48. +/- 0.25 D - ANS-ANSI for bifocal power
49. +/- 0.25 RGP
50. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power 10.12 D to 15.00 D
51. +/- 0.37 D - ANS-ANSI for cylinder 2.12 D to 4.00 D
52. +/- 0.37 RGP
53. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power 15.12 D to 20.00 D
54. +/- 0.50 D - ANS-a PMMA rigid lens wearer returns to the office for a follow up
keratometry. the readings obtained at this time should be within ___ of the original
readings.
55. +/- 0.50 RGP
56. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power over 20.00 D
57. +/- 4.00 D - ANS-at what point do contact lens powers need to be vertexed?
58. +/- 5 degrees - ANS-ANSI for axis over 1.50 D
59. +/- 8 degrees - ANS-ANSI for axis 0.50 D to 1.50 D
60. +1.25 - ANS-it is possible to extend the range of a keratometer to 61.00 diopters through
the use of an auxiliary trial lens with a power of:
61. +1.50 -3.50 x 164 - ANS-what is -2.00 +3.50 x 164 in minus cylinder form?
62. +11.00 D - ANS-spectacle RX = + 10.00 D
63. vertex distance = 10 mm
64. a rigid contact lens fit " on K " would require the following power:
65. +13.62 D - ANS-the CPC of a trial contact lens is 44.00 diopters and contains a power
equal to +14.87 D. the over refraction is equal to -1.62 D. what final lens power is
required if the CPC to be ordered is 43.62 diopter
, 66. +2.75 D - ANS-your patient is wearing a rigid contact lens in her right eye. it has a power
of +3.00 D and a base curve of 43.25. if the doctor refracts -0.50 sphere over this lens
and a new lens is to be ordered with a base curve of 43.00, what will the new power
need to be?
67. +6.50 D - ANS-what would be the soft contact lens power needed for a +6.00 D
spectacle lens?
68. 0.05 mm - ANS-when converting diopters to mm of radius, every 0.25 D equals
approximately:
69. 0.10 mm or 0.05 mm - ANS-when the power of a curve changes by a 0.50 or 0.25, the
radius of curvature changes be approximately:
70. 0.25 D - ANS-+/- 4.00 D to 5.75 D vertex
71. 0.25 D steeper than the lens ordered - ANS-a contact lens was ordered with a base
curve of 7.85 mm but was received back from the laboratory with a base curve
measuring 7.80 mm. the base curve of the actual lens is:
72. 0.50 D - ANS-+/- 6.00 D to 7.75 D vertex
73. 0.50 D - ANS-when moved 5 mm from its original position the effective power of a 10.00
diopter lens will change:
74. 0.50 D flatter than flat K - ANS-to achieve with a cornea, a good place to start is with a
base curve:
75. 0.50 D flatter` - ANS-the base curve of a rigid lens was ordered at 7.85 mm and was
received measuring 7.95 mm. this lens is ____________ than ordered
76. 0.50 D to 1.50 D - ANS-how much corneal astigmatism is ideal for an apical alignment
GP lens fit?
77. 0.75 D - ANS-+/- 8.00 D to 9.75 D vertex
78. 0.75 D - ANS-with how much refractive astigmatism should a soft toric lens design be
considered instead of a soft spherical lens
79. 0.75 D of refractive astigmatism - ANS-at what point should a toric lens be considered
for a soft lens candidate?
80. 020 - ANS-Rx: -7.00 -2.75 x 170
81. K: 43..00
82. when using a trial lens and slit lamp to evaluate the fit of a soft toric lens, you notice the
reference marking is positioned at 7 o clock. what is the cylinder axis of the lens to be
ordered?
83. 1 mm - ANS-how much overlap onto the sclera should there be in every direction for a
well fit soft lens?
84. 1 year - ANS-according to the FCLCA, how long is an RX valid if it is not specifically
noted?
85. 1-3 months - ANS-how often should a contact lens case be replaced?
86. 1.00 D - ANS-+/- 10.00 D
87. 11.7 mm - ANS-the average horizontal corneal diameter is:
88. 13 to 38 - ANS-prospective patients who fall within the following age group generally
provide the best prognosis for successful contact lens fitting:
89. 15.00D to 16.00D - ANS-the crystalline lens is responsible for approximately how much
refractive power
1. -1.50 -1.50 x 180 - ANS-what is -3.00 +1.50 x 90 in minus cylinder form?
2. -1.75 -1.25 x 180 - ANS-consider the following information and determine the lens power
the lens power to be ordered
3. RX -3.00 +1.25 x 90
4. diagnostic lens -3.00 -1.25 x 170
5. lens does not rotate
6. -2.50 D - ANS-if a GP lens is fit 1.00 D flatter than flat K and the RX is
7. -3.50 -0.25 x 180, what would be the power of the lens?
8. -3.00 -1.25 x 05 - ANS-consider the following information and determine the lens power
to be ordered
9. RX: -3.00 -1.25 x 180
10. diagnostic lens -3.00 -1.25 x 170
11. lens rotates 5 degrees to the viewer's left
12. -3.00 -1.25 x 10 - ANS-consider the following information and determine the lens power
to be ordered
13. RX: -3.00 -1.25 x 180
14. diagnostic lens -3.00 -1.25 x 180
15. lens rotates 10 degrees to the viewer's left
16. -3.00 -1.25 x 170 - ANS-consider the following information and determine the lens power
to be ordered.
17. RX: -3.00 -1.25 x 180
18. diagnostic lens -3.00 -1.25 x 170
19. lens rotates 10 degrees to the viewer's right
20. -3.00 D - ANS-RX -2.50 +0.25 x 90
21. vertex distance = 12 mm
22. if a contact lens is to be fit 0.75 diopters steeper than the flattest corneal meridian, what
would the power be? assume all the astigmatism is in the cornea
23. -3.00 D - ANS-RX -4.00 + 1.00 x 90
24. K: 42.50 @ 180/ 43.50 @ 90
25. a rigid contact lens fit " on K " would require the following power:
26. -3.00 D - ANS-what is the spherical equivalent of the RX -2.75 -0.50 x 180
27. -3.25 D - ANS-if a GP lens is fit 0.50 D steeper than flat K and the RX is
28. -2.75 -0.50 x 180, what would be the power of the lens?
29. -3.50 D - ANS-RX -3.00 -0.50 x 90
30. vertex distance = 11 mm
31. what is the power of a rigid contact lens fit 0.50 D steeper than the flattest corneal
meridian? assume all the astigmatism is in the cornea
32. -3.50 D - ANS-what is the spherical equivalent of the RX -3.75 +0.50 x 90
,33. -3.75` - ANS-your patient is wearing a rigid contact lens with a base curve of 42.50 and
power of -3.25 D. the doctor over refracts -0.75 over this lens. if the final lens to be
ordered will have a base curve of 42.25, what will its power have to be?
34. -4.00 D - ANS-a -3.50 D lens with a base curve of 44.50 provides excellent visual acuity.
if the CPC were changed to 45.00 D what power would be needed?
35. -5.00 D - ANS-what is the spherical equivalent of the RX -5.00 -0.50 x 180
36. -9.00 D - ANS-a spectacle lens is prescribed at -10.00 D provided that the lens is fit at a
vertex distance of 10 mm. a rigid contact lens fit " on K " for this patient would require a
power of:
37. + 14.00 D - ANS-RX + 11.00 + 1.00 x 20
38. vertex distance= 12 mm
39. what would be the power of a rigid contact lens fit " on K? "
40. +/- 0.02 RGP
41. SOFT HYDROGEL +/- 0.03 - ANS-ANSI for center thickness mm
42. +/- 0.05 mm - ANS-the BC of a RGP lens must be verified to be within _______ of that
specified
43. +/- 0.12 RGP
44. SOFT HYDROGEL +/- 0.25 - ANS-ANSI for power 0.00 D to 5.00 D
45. +/- 0.18 RGP
46. SOFT HYDROGEL +/- 0.25 - ANS-ANSI for power 5.12 D to 10.00 D
47. +/- 0.25 - ANS-ANSI for cylinder 0.00 D 2.00 D
48. +/- 0.25 D - ANS-ANSI for bifocal power
49. +/- 0.25 RGP
50. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power 10.12 D to 15.00 D
51. +/- 0.37 D - ANS-ANSI for cylinder 2.12 D to 4.00 D
52. +/- 0.37 RGP
53. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power 15.12 D to 20.00 D
54. +/- 0.50 D - ANS-a PMMA rigid lens wearer returns to the office for a follow up
keratometry. the readings obtained at this time should be within ___ of the original
readings.
55. +/- 0.50 RGP
56. SOFT HYDROGEL +/- 0.50 - ANS-ANSI for power over 20.00 D
57. +/- 4.00 D - ANS-at what point do contact lens powers need to be vertexed?
58. +/- 5 degrees - ANS-ANSI for axis over 1.50 D
59. +/- 8 degrees - ANS-ANSI for axis 0.50 D to 1.50 D
60. +1.25 - ANS-it is possible to extend the range of a keratometer to 61.00 diopters through
the use of an auxiliary trial lens with a power of:
61. +1.50 -3.50 x 164 - ANS-what is -2.00 +3.50 x 164 in minus cylinder form?
62. +11.00 D - ANS-spectacle RX = + 10.00 D
63. vertex distance = 10 mm
64. a rigid contact lens fit " on K " would require the following power:
65. +13.62 D - ANS-the CPC of a trial contact lens is 44.00 diopters and contains a power
equal to +14.87 D. the over refraction is equal to -1.62 D. what final lens power is
required if the CPC to be ordered is 43.62 diopter
, 66. +2.75 D - ANS-your patient is wearing a rigid contact lens in her right eye. it has a power
of +3.00 D and a base curve of 43.25. if the doctor refracts -0.50 sphere over this lens
and a new lens is to be ordered with a base curve of 43.00, what will the new power
need to be?
67. +6.50 D - ANS-what would be the soft contact lens power needed for a +6.00 D
spectacle lens?
68. 0.05 mm - ANS-when converting diopters to mm of radius, every 0.25 D equals
approximately:
69. 0.10 mm or 0.05 mm - ANS-when the power of a curve changes by a 0.50 or 0.25, the
radius of curvature changes be approximately:
70. 0.25 D - ANS-+/- 4.00 D to 5.75 D vertex
71. 0.25 D steeper than the lens ordered - ANS-a contact lens was ordered with a base
curve of 7.85 mm but was received back from the laboratory with a base curve
measuring 7.80 mm. the base curve of the actual lens is:
72. 0.50 D - ANS-+/- 6.00 D to 7.75 D vertex
73. 0.50 D - ANS-when moved 5 mm from its original position the effective power of a 10.00
diopter lens will change:
74. 0.50 D flatter than flat K - ANS-to achieve with a cornea, a good place to start is with a
base curve:
75. 0.50 D flatter` - ANS-the base curve of a rigid lens was ordered at 7.85 mm and was
received measuring 7.95 mm. this lens is ____________ than ordered
76. 0.50 D to 1.50 D - ANS-how much corneal astigmatism is ideal for an apical alignment
GP lens fit?
77. 0.75 D - ANS-+/- 8.00 D to 9.75 D vertex
78. 0.75 D - ANS-with how much refractive astigmatism should a soft toric lens design be
considered instead of a soft spherical lens
79. 0.75 D of refractive astigmatism - ANS-at what point should a toric lens be considered
for a soft lens candidate?
80. 020 - ANS-Rx: -7.00 -2.75 x 170
81. K: 43..00
82. when using a trial lens and slit lamp to evaluate the fit of a soft toric lens, you notice the
reference marking is positioned at 7 o clock. what is the cylinder axis of the lens to be
ordered?
83. 1 mm - ANS-how much overlap onto the sclera should there be in every direction for a
well fit soft lens?
84. 1 year - ANS-according to the FCLCA, how long is an RX valid if it is not specifically
noted?
85. 1-3 months - ANS-how often should a contact lens case be replaced?
86. 1.00 D - ANS-+/- 10.00 D
87. 11.7 mm - ANS-the average horizontal corneal diameter is:
88. 13 to 38 - ANS-prospective patients who fall within the following age group generally
provide the best prognosis for successful contact lens fitting:
89. 15.00D to 16.00D - ANS-the crystalline lens is responsible for approximately how much
refractive power
