NCLE Advanced Certification Exam Questions With Correct Answers Latest 2024 (GRADED)

NCLE Advanced Certification Exam Questions With Correct Answers Latest 2024 (GRADED) The posterior optical zone will directly affect the lens to cornea relationship of a rigid 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 the sagittal depth of the lens, nor will changing its edge design. - Answer 1. The sagittal depth of a rigid gas permeable contact lens can be altered without changing the diameter by: A. Changing the power 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 The answer is A. A lens is truncated by removing a segment of the lower edge of a contact lens. This 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. - Answer 2. A truncation is used on a rigid gas permeable contact lens to help enhance the performance of which type of design? A. Bifocal B. Aphakic C. Bitoric D. Keratoconus The answer is B. A lenticular or myoflange design will decrease the mass of an aphakic lens as well as increase the edge profile, which allows it to interact more with the upper lid and aid in positioning of the lens. - Answer 3. The mass of an aphakic rigid gas permeable contact lens can be reduced by making the lens design: A. Spherical B. Lenticular C. Tricurve D. Aspheric The answer is B. Increasing the optical zone diameter and increasing the overall lens diameter will both tighten and steepen the relationship of the lens to the cornea. Decreasing the 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 it relates to sagittal depth. - Answer 4. In order to tighten the fit of a rigid gas permeable lens you can: I. Increase the optical zone diameter 2. Decrease the optical zone diameter 3. Increase the overall lens diameter 4. Use a prism ballasted lens design A. 3 only B. 1&3 C. 2 only D. 2&3 The answer is D. A hyperflange will decrease edge thickness as well as lens awareness . Aspheric 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 lenses not high minus lenses. - Answer 5. A high minus rigid gas permeable lens will be thin centrally with relatively thick edges. To reduce the edge thickness, and increase overall comfort, use: A. Aspheric peripheral curves B. A myoflange C. A higher Dk material D. A hyperflange The answer is C. 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 anterior surface would add plus power. Applying polishing pressure to the central anterior surface would add minus power. - Answer 6. To add minus power to a rigid contact lens with a rotating modifying spindle, one would: A. Polish the posterior surface of the rigid lens B. Polish the mid peripheral anterior surface C. Polish the central anterior surface D. Polish the peripheral anterior surface The answer is A. The keratometer readings indicate the need for a spherical back surface, which would rule out the use of a bitoric lens. A soft spherical lens would not correct the 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 would correct the residual astigmatism. - Answer 7. Which lens design would provide the best visual acuity for a patient with the following information? K's 42.00@ 180/ 42.50@90 Rx -6.75 +1.75 cx 90 A. Front surface toric rigid gas permeable B. Spherical rigid gas permeable C. Soft sphere D. Bitoric rigid gas permeable The answer is A. The wetting angle of a rigid gas permeable material describes how a fluid spreads 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 wetting angle of the material is no longer important. - Answer 8. Which of the following describes the angle that the edge of a bead of water makes with the surface of a plastic? A. Wetting angle B. Surface angle C. Bead angle D. Reflection angle The answer is B. The back surface of a rigid lens will usually correct only the astigmatism that is 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. - Answer 9. If a patient has 1.50 D of refractive cylinder and keratometer readings of 44.00@ 180/ 44 .50 @ 90, a spherical rigid gas permeable lens will: A. Give the patient their best correctable vision B. Usually result in residual astigmatism C. Fit poorly D. Be uncomfortable The answer is C. Lenticular astigmatism usually exists when the amount of refractive cylinder is greater than the amount of corneal cylinder. It is assumed that the additional astigmatism originates in the crystalline lens. - Answer 10. If a patient has spherical K readings of 43.50 and an Rx of -4.00 +1.75 cx 90, the patient has: A. Corneal astigmatism B. Against the rule astigmatism C. Lenticular astigmatism NCLE Advanced Certification Exam With Correct Answers D. Mixed astigmatism The answer is B. 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 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 contour and not mask the irregularity. - Answer 11. In which of the following situations is a rigid gas permeable lens always preferred over a soft lens? A. Regular astigmatism B. Irregular astigmatism C. Aphakia D. Presbyopia The answer is A. Decreasing the optical zone diameter while steepening the base curve of a rigid gas 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 diameter also tightens the fit and will only exaggerate the change made to the lens 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. - Answer 12. In order to steepen the base curve of a rigid gas permeable lens without changing the lens to cornea relationship, you would also need to: A. Decrease the optical zone diameter B. Decrease the center thickness C. Increase the overall lens diameter D. Increase the lens power The answer is B. Increasing the overall lens diameter or increasing the optical zone diameter will steepen the lens to cornea relationship. Conversely, decreasing the optical zone 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 another is made that loosens it, the changes will cancel each other out. - Answer 13. To steepen the lens to cornea relationship of a rigid gas permeable lens you could : A. Increase overall diameter and decrease optical zone diameter 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 The answer is D. NCLE Advanced Certification Exam With Correct Answers 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 improve the positioning of a lens, reduce discomfort for the patient and eliminate corneal staining. - Answer 14. Which is not an indication for modifying a rigid gas permeable lens? A. Corneal staining B. Poor lens position C. Discomfort D. Surface Wettability The answer is D. 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, adding plus power, polishing the edges, polishing the anterior and posterior surfaces, as well as reducing lens diameter are all examples of modifications that can be performed in the office. - Answer 15. Which of the following modifications can be made to a rigid gas permeable lens in the office? A. Blending B. Changing the power C. Polishing the edge D. Changing the base curve The answer is A. Lenses that position temporally or inferiorly are not typically indicated and should be avoided. Lenses that position superiorly are often lenses that have been designed 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 fit intrapalpebrally or centrally. - Answer 16. To achieve a lens to cornea relationship that exhibits apical clearance, the lens is designed steeper than the flattest corneal measurement. This lens will most often position: A. Centrally B. Temporally C. Superiorly D. Inferiorly The answer is C. The two visual systems utilized by rigid gas permeable bifocals are simultaneous and alternating. With simultaneous vision systems, both near and far images are received by the retina at the same time. Concentric and aspheric bifocal lens designs utilize simulta- neous vision principles. With alternating vision systems, the lens will NCLE Advanced Certification Exam With Correct Answers move on the eye, delivering the focal length that is in front of the pupil as the lens translates . Segmented bifocal lens designs fall into this category. - Answer 17. Which of the following are visual systems used by rigid gas permeable bifocal lenses? A. Translating and hyperopic B. Simultaneous and instantaneous C. Simultaneous and alternating D. Truncated and prism ballasted The answer is D. Most translating or alternating rigid gas permeable bifocal lenses must be stabilized 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, the bottom portion of the lens is removed, producing a straight edge that interacts ·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 principles as prism ballasting of a soft toric lens, the thicker portion of the lens will be forced from under the upper lid to an inferior position. - Answer 18. Which of the following are methods for stabilizing the rotation of rigid bifocal contact lenses? A. Back surface toric and front surface toric B. Edge roll and polish C. Alternating and translating D. Truncation and prism ballast The answer is D. Flattening the base curve of the lens and decreasing the overall diameter will each decrease the sagittal depth of the contact lens. By combining both factors, the impact will be magnified. Steepening the base curve and increasing the overall diameter will both increase the sagittal depth. - Answer 19. To decrease the sagittal depth of a rigid gas permeable contact lens you can: 1. Steepen the base curve 2. Flatten the base curve 3. Increasetheoveralldiameter 4. Decrease the overall diameter A. 1and4 B. 1and3 C. 2and3 D. 2and4 The answer is B. NCLE Advanced Certification Exam With Correct Answers Dimple veil staining is not traditional staining but is rather a pooling of fluorescein in depressions or "dimples" on the surface of the cornea. These dimples are caused 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 the base curve is too steep and peripherally if the base curve or peripheral curves are too flat. - Answer 20. Dimple veil staining on the cornea is caused by: A. Poor polishing of peripheral curves B. Air bubbles trapped under a rigid lens C. Debris trapped under a rigid lens D. A cracked contact lens