NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
1. The sagittal depth of a rigid gas permeable contact The answer is D.
lens can be altered without changing the diameter The posterior optical zone will directly affect the lens to cornea relationship of a rigid
by: gas permeable lens. If the posterior optical zone is steepened, it will increase the
sagittal depth. If it is flattened, it will decrease the sagittal depth. Changing the
power, which is accomplished by changing the anterior optical zone, will not affect
A. Changing the power the sagittal depth of the lens, nor will changing its edge design.
B. Changing the edge design
C. Changing the radius of curvature of the anterior
optical zone
D. Changing the radius of curvature of the posterior
optical zone
2. A truncation is used on a rigid gas permeable The answer is A.
contact lens to help enhance the performance of A lens is truncated by removing a segment of the lower edge of a contact lens. This
which type of design? creates a straight edge that interacts with the lower lid and aids in lens positioning.
Of the lens designs listed in the question, the only one that requires precise
positioning of its optical portions is a translating bifocal lens.
A. Bifocal
B. Aphakic
C. Bitoric
D. Keratoconus
3. The mass of an aphakic rigid gas permeable The answer is B.
contact lens can be reduced by making the lens A lenticular or myoflange design will decrease the mass of an aphakic lens as well
design: as increase the edge profile, which allows it to interact more with the upper lid and
aid in positioning of the lens.
A. Spherical
B. Lenticular
C. Tricurve
D. Aspheric
4. In order to tighten the fit of a rigid gas permeable The answer is B.
lens you can: Increasing the optical zone diameter and increasing the overall lens diameter will
I. Increase the optical zone diameter both tighten and steepen the relationship of the lens to the cornea. Decreasing the
2. Decrease the optical zone diameter optic zone diameter will serve to flatten and loosen the lens to cornea relationship.
Using a prism-ballasted lens design will not affect the lens to cornea relationship as
3. Increase the overall lens diameter it relates to sagittal depth.
4. Use a prism ballasted lens design
A. 3 only
B. 1&3
C. 2 only
D. 2&3
5. A high minus rigid gas permeable lens will be thin The answer is D.
centrally with relatively thick edges. To reduce the A hyperflange will decrease edge thickness as well as lens awareness . Aspheric
edge thickness, and increase overall comfort, use: peripheral curves change the posterior design of the lens but do not reduce edge
thickness. A higher Dk material will not change the overall lens edge thickness. A
myoflange will actually add thickness to the lens edge and is used for high plus
A. Aspheric peripheral curves lenses not high minus lenses.
B. A myoflange
C. A higher Dk material
D. A hyperflange
,NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
6. To add minus power to a rigid contact lens with a The answer is C.
rotating modifying spindle, one would: One would rarely polish or attempt to manipulate the central posterior surface of a
rigid lens. Applying polishing pressure to the mid-peripheral and the peripheral
A. Polish the posterior surface of the rigid lens anterior surface would add plus power. Applying polishing pressure to the central
anterior surface would add minus power.
B. Polish the mid peripheral anterior surface
C. Polish the central anterior surface
D. Polish the peripheral anterior surface
7. Which lens design would provide the best visual The answer is A.
acuity for a patient with the following information? The keratometer readings indicate the need for a spherical back surface, which
K's 42.00@ 180/ 42.50@90 would rule out the use of a bitoric lens. A soft spherical lens would not correct the
Rx -6.75 +1.75 cx 90 moderate amount of refractive astigmatism that is present, nor would the spherical
rigid gas permeable lens. A front surface toric RGP would best meet this patient's
needs since it has a spherical back surface, but has a toric front surface which
A. Front surface toric rigid gas permeable would correct the residual astigmatism.
B. Spherical rigid gas permeable
C. Soft sphere
D. Bitoric rigid gas permeable
8. Which of the following describes the angle that the The answer is A.
edge of a bead of water makes with the surface of a The wetting angle of a rigid gas permeable material describes how a fluid spreads
plastic? over the surface. It is important to remember, however, that wetting angle is a
description of the material outside of the patient's natural ocular environment. Within
minutes of insertion, a rigid lens is encapsulated in the natural tear mucin and the
A. Wetting angle wetting angle of the material is no longer important.
B. Surface angle
C. Bead angle
D. Reflection angle
9. If a patient has 1.50 D of refractive cylinder and The answer is B.
keratometer readings of 44.00@ 180/ 44 .50 @ 90, a The back surface of a rigid lens will usually correct only the astigmatism that is
spherical rigid gas permeable lens will: found on the surface of the cornea. Therefore, when there is significantly more
astigmatism in the refraction than on the surface of the cornea, residual astigmatism
is anticipated.
A. Give the patient their best correctable vision
B. Usually result in residual astigmatism
C. Fit poorly
D. Be uncomfortable
10. If a patient has spherical K readings of 43.50 and The answer is C.
an Rx of -4.00 +1.75 cx 90, the patient has: Lenticular astigmatism usually exists when the amount of refractive cylinder is
greater than the amount of corneal cylinder. It is assumed that the additional
A. Corneal astigmatism astigmatism originates in the crystalline lens.
B. Against the rule astigmatism
C. Lenticular astigmatism
D. Mixed astigmatism
11. In which of the following situations is a rigid gas The answer is B.
permeable lens always preferred over a soft lens? With regular astigmatism, even high degrees, a soft toric lens can work quite
effectively. Presbyopic and aphakic patients can also be successfully fit with soft
A. Regular astigmatism lenses. However, patients with irregular astigmatism will achieve their best visual
acuity only with rigid gas permeable lenses since soft lenses will mold to the corneal
B. Irregular astigmatism contour and not mask the irregularity.
C. Aphakia
D. Presbyopia
,NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
12. In order to steepen the base curve of a rigid gas The answer is A.
permeable lens without changing the lens to cornea Decreasing the optical zone diameter while steepening the base curve of a rigid gas
relationship, you would also need to: permeable lens will allow the lens to cornea relationship to remain the same, since
decreasing the optical zone diameter loosens the lens to cornea relationship and
steepen- ing the base curve tightens the relationship. Increasing the overall lens
A. Decrease the optical zone diameter diameter also tightens the fit and will only exaggerate the change made to the lens
B. Decrease the center thickness to cornea relationship. Decreasing the center thickness or increasing the lens power
will have no significant effect on the relationship of the lens to the cornea.
C. Increase the overall lens diameter
D. Increase the lens power
13. To steepen the lens to cornea relationship of a The answer is B.
rigid gas permeable lens you could : Increasing the overall lens diameter or increasing the optical zone diameter will
steepen the lens to cornea relationship. Conversely, decreasing the optical zone
A. Increase overall diameter and decrease optical diameter, decreasing the overall lens diameter or flattening the base curve will
loosen the relationship. If one change is made that tightens the relationship and
zone diameter another is made that loosens it, the changes will cancel each other out.
B. Increase overall diameter and increase optical zone
diameter
C. Increase optical zone diameter and decrease
overall diameter
D. Increase optical zone diameter and flatten base
curve
14. Which is not an indication for modifying a rigid The answer is D.
gas permeable lens? Modification of rigid gas permeable lenses is a valuable skill and can increase a
practitioner's success at RGP fitting. Many in-office modifications can be utilized to
A. Corneal staining improve the positioning of a lens, reduce discomfort for the patient and eliminate
corneal staining.
B. Poor lens position
C. Discomfort
D. Surface Wettability
15. Which of the following modifications can be The answer is D.
made to a rigid gas permeable lens in the office? Many modifi~ations to rigid gas permeable lenses can be done in the office, saving
time and improving service. Blending peripheral curves, adding minus power,
A. Blending adding plus power, polishing the edges, polishing the anterior and posterior
surfaces, as well as reducing lens diameter are all examples of modifications that
B. Changing the power can be performed in the office.
C. Polishing the edge
D. Changing the base curve
16. To achieve a lens to cornea relationship that The answer is A.
exhibits apical clearance, the lens is designed Lenses that position temporally or inferiorly are not typically indicated and should be
steeper than the flattest corneal measurement. This avoided. Lenses that position superiorly are often lenses that have been designed
lens will most often position: with the apical alignment philosophy and have been fit flatter than the flattest
keratometer reading in order to achieve this alignment. Lenses that are fit with
apical clearance are fit steeper than the flattest corneal measurement and often will
A. Centrally fit intrapalpebrally or centrally.
B. Temporally
C. Superiorly
D. Inferiorly
, NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
17. Which of the following are visual systems used by The answer is C.
rigid gas permeable bifocal lenses? The two visual systems utilized by rigid gas permeable bifocals are simultaneous
and alternating. With simultaneous vision systems, both near and far images are
A. Translating and hyperopic received by the retina at the same time. Concentric and aspheric bifocal lens
designs utilize simulta- neous vision principles. With alternating vision systems, the
B. Simultaneous and instantaneous lens will move on the eye, delivering the focal length that is in front of the pupil as
C. Simultaneous and alternating the lens translates . Segmented bifocal lens designs fall into this category.
D. Truncated and prism ballasted
18. Which of the following are methods for The answer is D.
stabilizing the rotation of rigid bifocal contact Most translating or alternating rigid gas permeable bifocal lenses must be stabilized
lenses? in
order for the proper segment to align correctly with the pupil. Two methods of
accomplishing this are by truncating and/ or prism ballasting the lens. In truncation,
A. Back surface toric and front surface toric the bottom portion of the lens is removed, producing a straight edge that interacts
B. Edge roll and polish ·with the lid and aligns the lens in its proper position. With prism ballasting, the
bottom portion of the lens is made thicker than the top portion. Following the same
C. Alternating and translating principles as prism ballasting of a soft toric lens, the thicker portion of the lens will
D. Truncation and prism ballast be forced from under the upper lid to an inferior position.
19. To decrease the sagittal depth of a rigid gas The answer is D.
permeable contact lens you can: Flattening the base curve of the lens and decreasing the overall diameter will each
1. Steepen the base curve decrease the sagittal depth of the contact lens. By combining both factors, the
2. Flatten the base curve impact will be magnified. Steepening the base curve and increasing the overall
diameter will both increase the sagittal depth.
3. Increasetheoveralldiameter
4. Decrease the overall diameter
A. 1and4
B. 1and3
C. 2and3
D. 2and4
20. Dimple veil staining on the cornea is caused by: The answer is B.
Dimple veil staining is not traditional staining but is rather a pooling of fluorescein in
A. Poor polishing of peripheral curves depressions or "dimples" on the surface of the cornea. These dimples are caused
B. Air bubbles trapped under a rigid lens by air bubbles that become trapped behind a rigid lens in an area where the
distance between the lens and cornea is too great. Dimples will be found centrally if
C. Debris trapped under a rigid lens the base curve is too steep and peripherally if the base curve or peripheral curves
D. A cracked contact lens are too flat.
21. The GP multifocal design that relies on the use of The answer is B.
a variable rate of curvature across the lens surface to The parameters listed in C and D will flatten the lens to cornea relationship. While
achieve a change in power is known as: answer A does steepen the lens' relationship, it does not take into account the
change in the power that is necessary when the base curve of the lens is altered.
A. Concentric
B. Translating
C. Aspheric
D. Truncated
1. The sagittal depth of a rigid gas permeable contact The answer is D.
lens can be altered without changing the diameter The posterior optical zone will directly affect the lens to cornea relationship of a rigid
by: gas permeable lens. If the posterior optical zone is steepened, it will increase the
sagittal depth. If it is flattened, it will decrease the sagittal depth. Changing the
power, which is accomplished by changing the anterior optical zone, will not affect
A. Changing the power the sagittal depth of the lens, nor will changing its edge design.
B. Changing the edge design
C. Changing the radius of curvature of the anterior
optical zone
D. Changing the radius of curvature of the posterior
optical zone
2. A truncation is used on a rigid gas permeable The answer is A.
contact lens to help enhance the performance of A lens is truncated by removing a segment of the lower edge of a contact lens. This
which type of design? creates a straight edge that interacts with the lower lid and aids in lens positioning.
Of the lens designs listed in the question, the only one that requires precise
positioning of its optical portions is a translating bifocal lens.
A. Bifocal
B. Aphakic
C. Bitoric
D. Keratoconus
3. The mass of an aphakic rigid gas permeable The answer is B.
contact lens can be reduced by making the lens A lenticular or myoflange design will decrease the mass of an aphakic lens as well
design: as increase the edge profile, which allows it to interact more with the upper lid and
aid in positioning of the lens.
A. Spherical
B. Lenticular
C. Tricurve
D. Aspheric
4. In order to tighten the fit of a rigid gas permeable The answer is B.
lens you can: Increasing the optical zone diameter and increasing the overall lens diameter will
I. Increase the optical zone diameter both tighten and steepen the relationship of the lens to the cornea. Decreasing the
2. Decrease the optical zone diameter optic zone diameter will serve to flatten and loosen the lens to cornea relationship.
Using a prism-ballasted lens design will not affect the lens to cornea relationship as
3. Increase the overall lens diameter it relates to sagittal depth.
4. Use a prism ballasted lens design
A. 3 only
B. 1&3
C. 2 only
D. 2&3
5. A high minus rigid gas permeable lens will be thin The answer is D.
centrally with relatively thick edges. To reduce the A hyperflange will decrease edge thickness as well as lens awareness . Aspheric
edge thickness, and increase overall comfort, use: peripheral curves change the posterior design of the lens but do not reduce edge
thickness. A higher Dk material will not change the overall lens edge thickness. A
myoflange will actually add thickness to the lens edge and is used for high plus
A. Aspheric peripheral curves lenses not high minus lenses.
B. A myoflange
C. A higher Dk material
D. A hyperflange
,NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
6. To add minus power to a rigid contact lens with a The answer is C.
rotating modifying spindle, one would: One would rarely polish or attempt to manipulate the central posterior surface of a
rigid lens. Applying polishing pressure to the mid-peripheral and the peripheral
A. Polish the posterior surface of the rigid lens anterior surface would add plus power. Applying polishing pressure to the central
anterior surface would add minus power.
B. Polish the mid peripheral anterior surface
C. Polish the central anterior surface
D. Polish the peripheral anterior surface
7. Which lens design would provide the best visual The answer is A.
acuity for a patient with the following information? The keratometer readings indicate the need for a spherical back surface, which
K's 42.00@ 180/ 42.50@90 would rule out the use of a bitoric lens. A soft spherical lens would not correct the
Rx -6.75 +1.75 cx 90 moderate amount of refractive astigmatism that is present, nor would the spherical
rigid gas permeable lens. A front surface toric RGP would best meet this patient's
needs since it has a spherical back surface, but has a toric front surface which
A. Front surface toric rigid gas permeable would correct the residual astigmatism.
B. Spherical rigid gas permeable
C. Soft sphere
D. Bitoric rigid gas permeable
8. Which of the following describes the angle that the The answer is A.
edge of a bead of water makes with the surface of a The wetting angle of a rigid gas permeable material describes how a fluid spreads
plastic? over the surface. It is important to remember, however, that wetting angle is a
description of the material outside of the patient's natural ocular environment. Within
minutes of insertion, a rigid lens is encapsulated in the natural tear mucin and the
A. Wetting angle wetting angle of the material is no longer important.
B. Surface angle
C. Bead angle
D. Reflection angle
9. If a patient has 1.50 D of refractive cylinder and The answer is B.
keratometer readings of 44.00@ 180/ 44 .50 @ 90, a The back surface of a rigid lens will usually correct only the astigmatism that is
spherical rigid gas permeable lens will: found on the surface of the cornea. Therefore, when there is significantly more
astigmatism in the refraction than on the surface of the cornea, residual astigmatism
is anticipated.
A. Give the patient their best correctable vision
B. Usually result in residual astigmatism
C. Fit poorly
D. Be uncomfortable
10. If a patient has spherical K readings of 43.50 and The answer is C.
an Rx of -4.00 +1.75 cx 90, the patient has: Lenticular astigmatism usually exists when the amount of refractive cylinder is
greater than the amount of corneal cylinder. It is assumed that the additional
A. Corneal astigmatism astigmatism originates in the crystalline lens.
B. Against the rule astigmatism
C. Lenticular astigmatism
D. Mixed astigmatism
11. In which of the following situations is a rigid gas The answer is B.
permeable lens always preferred over a soft lens? With regular astigmatism, even high degrees, a soft toric lens can work quite
effectively. Presbyopic and aphakic patients can also be successfully fit with soft
A. Regular astigmatism lenses. However, patients with irregular astigmatism will achieve their best visual
acuity only with rigid gas permeable lenses since soft lenses will mold to the corneal
B. Irregular astigmatism contour and not mask the irregularity.
C. Aphakia
D. Presbyopia
,NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
12. In order to steepen the base curve of a rigid gas The answer is A.
permeable lens without changing the lens to cornea Decreasing the optical zone diameter while steepening the base curve of a rigid gas
relationship, you would also need to: permeable lens will allow the lens to cornea relationship to remain the same, since
decreasing the optical zone diameter loosens the lens to cornea relationship and
steepen- ing the base curve tightens the relationship. Increasing the overall lens
A. Decrease the optical zone diameter diameter also tightens the fit and will only exaggerate the change made to the lens
B. Decrease the center thickness to cornea relationship. Decreasing the center thickness or increasing the lens power
will have no significant effect on the relationship of the lens to the cornea.
C. Increase the overall lens diameter
D. Increase the lens power
13. To steepen the lens to cornea relationship of a The answer is B.
rigid gas permeable lens you could : Increasing the overall lens diameter or increasing the optical zone diameter will
steepen the lens to cornea relationship. Conversely, decreasing the optical zone
A. Increase overall diameter and decrease optical diameter, decreasing the overall lens diameter or flattening the base curve will
loosen the relationship. If one change is made that tightens the relationship and
zone diameter another is made that loosens it, the changes will cancel each other out.
B. Increase overall diameter and increase optical zone
diameter
C. Increase optical zone diameter and decrease
overall diameter
D. Increase optical zone diameter and flatten base
curve
14. Which is not an indication for modifying a rigid The answer is D.
gas permeable lens? Modification of rigid gas permeable lenses is a valuable skill and can increase a
practitioner's success at RGP fitting. Many in-office modifications can be utilized to
A. Corneal staining improve the positioning of a lens, reduce discomfort for the patient and eliminate
corneal staining.
B. Poor lens position
C. Discomfort
D. Surface Wettability
15. Which of the following modifications can be The answer is D.
made to a rigid gas permeable lens in the office? Many modifi~ations to rigid gas permeable lenses can be done in the office, saving
time and improving service. Blending peripheral curves, adding minus power,
A. Blending adding plus power, polishing the edges, polishing the anterior and posterior
surfaces, as well as reducing lens diameter are all examples of modifications that
B. Changing the power can be performed in the office.
C. Polishing the edge
D. Changing the base curve
16. To achieve a lens to cornea relationship that The answer is A.
exhibits apical clearance, the lens is designed Lenses that position temporally or inferiorly are not typically indicated and should be
steeper than the flattest corneal measurement. This avoided. Lenses that position superiorly are often lenses that have been designed
lens will most often position: with the apical alignment philosophy and have been fit flatter than the flattest
keratometer reading in order to achieve this alignment. Lenses that are fit with
apical clearance are fit steeper than the flattest corneal measurement and often will
A. Centrally fit intrapalpebrally or centrally.
B. Temporally
C. Superiorly
D. Inferiorly
, NCLE Advanced Certification Exam | Comprehensive Exam Review & Practice Questions | 2025-2026
17. Which of the following are visual systems used by The answer is C.
rigid gas permeable bifocal lenses? The two visual systems utilized by rigid gas permeable bifocals are simultaneous
and alternating. With simultaneous vision systems, both near and far images are
A. Translating and hyperopic received by the retina at the same time. Concentric and aspheric bifocal lens
designs utilize simulta- neous vision principles. With alternating vision systems, the
B. Simultaneous and instantaneous lens will move on the eye, delivering the focal length that is in front of the pupil as
C. Simultaneous and alternating the lens translates . Segmented bifocal lens designs fall into this category.
D. Truncated and prism ballasted
18. Which of the following are methods for The answer is D.
stabilizing the rotation of rigid bifocal contact Most translating or alternating rigid gas permeable bifocal lenses must be stabilized
lenses? in
order for the proper segment to align correctly with the pupil. Two methods of
accomplishing this are by truncating and/ or prism ballasting the lens. In truncation,
A. Back surface toric and front surface toric the bottom portion of the lens is removed, producing a straight edge that interacts
B. Edge roll and polish ·with the lid and aligns the lens in its proper position. With prism ballasting, the
bottom portion of the lens is made thicker than the top portion. Following the same
C. Alternating and translating principles as prism ballasting of a soft toric lens, the thicker portion of the lens will
D. Truncation and prism ballast be forced from under the upper lid to an inferior position.
19. To decrease the sagittal depth of a rigid gas The answer is D.
permeable contact lens you can: Flattening the base curve of the lens and decreasing the overall diameter will each
1. Steepen the base curve decrease the sagittal depth of the contact lens. By combining both factors, the
2. Flatten the base curve impact will be magnified. Steepening the base curve and increasing the overall
diameter will both increase the sagittal depth.
3. Increasetheoveralldiameter
4. Decrease the overall diameter
A. 1and4
B. 1and3
C. 2and3
D. 2and4
20. Dimple veil staining on the cornea is caused by: The answer is B.
Dimple veil staining is not traditional staining but is rather a pooling of fluorescein in
A. Poor polishing of peripheral curves depressions or "dimples" on the surface of the cornea. These dimples are caused
B. Air bubbles trapped under a rigid lens by air bubbles that become trapped behind a rigid lens in an area where the
distance between the lens and cornea is too great. Dimples will be found centrally if
C. Debris trapped under a rigid lens the base curve is too steep and peripherally if the base curve or peripheral curves
D. A cracked contact lens are too flat.
21. The GP multifocal design that relies on the use of The answer is B.
a variable rate of curvature across the lens surface to The parameters listed in C and D will flatten the lens to cornea relationship. While
achieve a change in power is known as: answer A does steepen the lens' relationship, it does not take into account the
change in the power that is necessary when the base curve of the lens is altered.
A. Concentric
B. Translating
C. Aspheric
D. Truncated
