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| 1. Which of the following is not a cause of astigmatism? |
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A.
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astigmatism due to the cornea |
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B.
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astigmatism due to the crystalline lens |
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C.
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irregularities in the surface of the retina |
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D.
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the portion of the anterior corneal surface that is not neutralized by the tear lens. |
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| 2. What percentage of the patients has astigmatism .50 and 1.00 diopters? |
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A.
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20 percent |
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B.
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35 percent |
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C.
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45 percent |
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D.
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3 percent |
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| 3. Total astigmatism does not consist of which type of astigmatism? |
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A.
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corneal astigmatism |
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B.
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internal astigmatism |
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C.
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residual astigmatism |
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D.
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refractive astigmatism |
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| 4. What is the total astigmatism in the following example? Rx -75 -.75 x 180 |
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A.
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-4.75 sphere |
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B.
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-.75 x 180 |
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C.
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-.75 x 90 |
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D.
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-.75 x 145 |
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| 5. What is the amount of lenticular astigmatism in the following example? Rx +3.00 -1.75 x 180. “K” 44.00@180/44.75@90 |
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A.
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-.75 x 180 |
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B.
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-.75 x 90 |
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C.
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-1.00 x 180 |
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D.
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-1.00 x 90 |
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| 6. Which of the following K readings corresponds to “with-the-rule” astigmatism? |
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A.
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46.00@180/45.00@90 |
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B.
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44.00@180/44.00@90 |
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C.
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46.00 @180/45.75@90 |
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D.
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44.00@180/44.75@90 |
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| 7. In order to calculate residual astigmatism, the following is needed? |
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A.
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spectacle prescription |
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B.
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keratometer readings |
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C.
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corneal topography |
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D.
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a and b |
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| 8. Astigmatism that manifests itself after a contact lens is placed on the cornea is referred to as: |
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A.
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corneal astigmatism |
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B.
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lenticular astigmatism |
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C.
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residual astigmatism |
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D.
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total astigmatism |
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| 9. Which of the following may cause residual astigmatism? |
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A.
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titlted lenticular surface |
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B.
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anterior toric corneal surface not neutralized by the tear lens |
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C.
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an eccentric position of the fovea in relation to the visual axis |
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D.
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all of the above |
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| 10. Which type of astigmatism is more common in relation to keratometry readings? |
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A.
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with-the-rule astigmatism |
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B.
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against-the-rule astigmatism |
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C.
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irregular astigmatism |
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D.
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oblique astigmatism |
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| 11. The amount of astigmatism revealed by a sphero-cylinder refraction over a spherical contact lens is considered the amount of: |
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A.
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lenticular astigmatism |
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B.
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corneal astigmatism |
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C.
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residual astigmatism |
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D.
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irregular astigmatism |
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| 12. If a patient has one diopter of WTR corneal astigmatism and wears spectacles that correct for one diopter of WTR astigmatism, which contact lens would provide the best visual acuity? |
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A.
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soft lens |
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B.
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rigid lens |
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C.
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rigid front toric |
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D.
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bitoric lens |
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| 13. A patient has the following Rx -2.75 -100 x 90. What is the expected spherical equilvalent for this Rx? |
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A.
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-2.75 |
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B.
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-3.25 |
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C.
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-3.75 |
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D.
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-4.25 |
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| 14. A patient has a -5.25 spectacle Rx, “K” reading 42.00/43.00@90. With which contact lens should this patient be fit with? |
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A.
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rigid lens |
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B.
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soft toric lens |
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C.
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soft lens |
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D.
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rigid toric lens |
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| 15. A patient has a spherical cornea, but wears a 1.75 cylinder in spectacles to fully correct their ametropia. What type of lens would be indicated for this patient? |
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A.
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spherical rigid lens |
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B.
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front cylinder lens |
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C.
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bitoric lens |
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D.
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toric back curve |
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| 16. A patient has a “K” reading of 43.00@180/43.75@90. The spectacle Rx is -4.00 -.50 x 90. What is the anticipated residual astigmatism if a rigid lens is fit on this patient? |
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A.
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-.75 x 180 |
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B.
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-.50 x 90 |
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C.
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-1.25 x 180 |
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D.
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-1.25 x 90 |
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| 17. Using the information in the above example, what is the anticipated residual astigmatism with a soft lens? |
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A.
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-.75 x 180 |
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B.
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-.50 x 90 |
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C.
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-1.25 x 90 |
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D.
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none |
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| 18. Which of the following “K” readings will correspond with “against-the-rule” astigmatism? |
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A.
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46.00@180/47.00@90 |
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B.
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41.00@180/40.00@90 |
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C.
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41.00@135/41.00@45 |
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D.
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40.00@180/41.00@90 |
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| 19. Eyeglasses will not accurately correct what type of astigmatism? |
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A.
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ATR astigmatism |
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B.
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WTR astigmatism |
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C.
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Oblique astigmatism |
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D.
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Irregular astigmatism |
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| 20. Residual astigmatism with spherical soft lenses is usually equal to: |
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A.
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corneal astigmatism |
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B.
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lenticular astigmatism |
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C.
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refractive astigmatism |
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D.
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irregular astigmatism |
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