Training may improve reading performance. As mentioned above, prisms may facilitate the use of an extrafoveal PRL. Research is evaluating best practices.
Instruction and Training
It should be emphasized that for most patients, some instruction, training, and practice will be needed for them to be successful at accomplishing tasks with any of the devices or techniques described here. The use of computer accessibility features, video magnifiers, hand magnifiers, high-add spectacles, and adaptations for activities of daily living is not intuitive. Training with respect to nonoptical strategies, including safety measures, is equally important. Training sessions should be given to the patient, and preferably also to a family member or friend, who can later reinforce the training.
Chapter Exercises
Questions
7.1.The basic design of a slit-lamp biomicroscope includes all of the following except
a.a Galilean magnification changer
b.an astronomical telescope
c.a single monocular viewing system
d.an illumination system
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7.2. The corneal endothelium may be viewed using the slit-lamp biomicroscope by using which of the following techniques?
a.sclerotic scatter
b.direct illumination
c.proximal illumination
d.specular reflection
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7.3. In what way is the manual (von Helmholtz) keratometer inaccurate for determining corneal power in intraocular lens calculations following myopic laser vision correction?
a.The keratometer mire cannot be imaged at all following laser vision correction.
b.The assumed relationship between the anterior and posterior surfaces, which is the basis of the assumed index of refraction, is no longer accurate.
c.Significant irregular astigmatism is present in all corneas that have undergone keratorefractive surgery, and the keratometer is no longer accurate.
d.The keratometry measurement of the posterior surface does not change and is still accurate.
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7.4. You are planning cataract surgery to achieve emmetropia for a patient with the following measurements:
Refraction: –3.00 +2.00 × 120
K: 42.50 D/42.75 D @ 120°
Which of the following plans is the best option?
a.toric IOL with minus cylinder axis at 120 degrees
b.relaxing incision at 30 degrees
c.relaxing incision at 120 degrees
d.monofocal intraocular lens
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7.5.What is the size, in M notation, of the optotypes that are just visible to a patient with 20/20 visual acuity at the standard reading distance of 40 cm?
a.0.2 M
b.0.4 M
c.0.6 M
d.0.8 M
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7.6. According to the Kestenbaum rule, what is the appropriate reading add power for a patient with best-corrected visual acuity at a distance of 20/80 who wishes to read 1.0 M type?
a.2.0 D
b.3.0 D
c.4.0 D
d.5.0 D
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7.7. 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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7.8. The patient described in question 7.6 will read 1.0 M type at a distance of 25 cm, or approximately 10 inches, using his 4.0 D add spectacles. To alleviate the need to converge the eyes for extended periods when reading at such a close distance, what is the appropriate prism correction to incorporate into the high-add spectacles?
a.4Δ base-out OU
b.4Δ base-in OU
c.6Δ base-out OU
d.6Δ base-in OU
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7.9. When a binocular indirect ophthalmoscope is used with a patient with small pupils, binocular visualization can be improved by
a.moving the ophthalmoscope’s mirror closer to the observer
b.narrowing the observer’s effective interpupillary distance
c.moving the ophthalmoscope’s eyepieces farther apart
d.increasing the distance between the observer’s head and the patient
e.all of the above
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7.10.Which of the following statements is not true for how keratometers work?
a.They measure the radius of curvature of the central cornea.
b.They assume the cornea to be a convex mirror.
c.They directly measure the refractive power of the cornea.
d.They use a mathematical formula to convert radius of curvature to approximate refractive power.
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7.11.Which of the following devices is not an optical component of the slit-lamp biomicroscope?
a.field lens
b.astronomical telescope
c.inverting prism
d.Galilean magnification changer
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7.12. Proper distance visual acuity testing for a low vision patient includes all of the following except
a.a testing chart with an equal number of symbols on each line
b.nonstandardized room illumination
c.a Snellen visual acuity chart at 20 feet
d.a test distance of 10 feet
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7.13. A patient with moderately low vision (20/160 in each eye) requests a prescription to be able to read. Which of the following would be the best choice?
a. a +8.00 D single-vision reading spectacle