2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Chapter 8: Optical Instruments
Chapter Exercises
Questions
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8.1. Slit-lamp biomicroscopy enables viewing of the corneal endothelium using which technique?
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retroillumination
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specular reflection
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direct focal illumination
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sclerotic scatter
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8.2. Which statement does not characterize how keratometers work?
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They measure the radius of curvature of the central cornea.
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They assume the cornea to be a convex mirror.
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They directly measure the refractive power of the cornea.
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They use a mathematical formula to convert radius of curvature to approximate refractive power.
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8.3. In what way is the manual keratometer inaccurate for determining corneal power in intraocular lens calculations following myopic laser vision correction?
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The keratometry measurement of the posterior surface does not change and is still accurate.
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The keratometer mire cannot be imaged at all following laser vision correction.
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The assumed relationship between the anterior and posterior surfaces, which is the basis of the assumed index of refraction, is no longer accurate.
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Significant irregular astigmatism is present in all corneas that have undergone keratorefractive surgery, and the keratometer is no longer accurate.
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8.4. The indirect ophthalmoscope employs one of the brightest light sources used in clinical ophthalmology. Why is such a bright light necessary?
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8.5. Which statement is inaccurate for fundus examination with the direct ophthalmoscope?
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The optic disc will appear larger in a myopic eye than a normal or hyperopic eye.
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The optic disc will appear smaller in a myopic eye than a normal or hyperopic eye.
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The optic disc will appear smaller in a hyperopic eye than a normal or myopic eye.
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Smaller details can be observed than with the indirect ophthalmoscope.
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8.6. When a binocular indirect ophthalmoscope is used with a patient with small pupils, binocular visualization can be improved by which technique?
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moving the ophthalmoscope’s mirrors or prisms closer to the observer
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narrowing the observer’s effective interpupillary distance
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moving the ophthalmoscope’s eyepieces farther apart
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increasing the distance between the observer’s head and the patient
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all of the above
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.