Download VSII Final 2005-Smith section

Test A
Vision Science II
Opto 5221
April 27, 2005
Final Examination
Multiple choice - mark the most appropriate answer on the computer scoring sheet. If you have
concerns over a given question, write you concerns on your test and turn it in with your answer
sheet. Be sure to put your name on the test and indicate on the top of the front page which
questions I should examine.
Note: Unless otherwise specified all refractive errors are principle plane or ocular refractive
errors. Use Emsley’s reduced eye model for all calculations unless specified otherwise.
RSM=relative spectacle magnification; SM=spectacle magnification.
1. Which of the following statements concerning the refractive errors in newborn infants is NOT
correct?
a. The distribution of refractive errors is similar in shape to a random Gaussian
distribution.
b. In comparison to children 3-5 years of age, newborns exhibit a lower prevalence of
larger refractive errors.
c. Premature infant are generally more myopic than full-term infants.
d. The average refractive error is about +2.5 D of hyperopia.
e. The shape of the distribution of refractive errors is symmetric about the mean.
2. Which of the following statements best describes the refractive error distribution for the young
adult population?
a. The distribution is platykurtic because there are more clinical emmetropes than
predicted on the basis of chance.
b. The distribution conforms to a random Gaussian distribution, which suggests that
refractive error is determined primarily by chance.
c. The distribution is leptokurtic with more clinical emmetropes, fewer individuals with
moderate refractive errors (e.g., -3.0 D), and more individuals with larger refractive
errors (>+6.0 D) than predicted on the basis of chance.
d. The distribution is leptokurtic with more clinical emmetropes, fewer individuals with
moderate refractive errors (e.g., -3.0 D), and fewer individuals with larger refractive
errors (>+6.0 D) than predicted on the basis of chance.
e. The distribution is leptokurtic with more clinical emmetropes, more individuals with
moderate refractive errors (e.g., -3.0 D), and fewer individuals with larger refractive
errors (>+6.0 D) than predicted on the basis of chance.
3. Which of the following age groups would probably include the greatest proportion of myopic
individuals?
a. 3-4 years
b. 8-10 years
c. 25-30 years
d. 45-50 years
e. 55-65 years
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Test A
4. Emmetropization is typically complete by _____________.
a. 1 month of age
b. 9 months of age
c. 18 months of age
d. 6 years of age
e. 16 years of age
5. Approximately how much does the eye normally increase in axial length during the first 3
years of age?
a. 500-600 microns
b. 1-2 mm
c. 8-10 mm
d. 5-6 mm
e. 3500 microns
6. With respect to the interocular balance of refractive errors during early infancy (0-3 yrs),
which of the following statements is correct?
a. Only 1 out of every 100 infants will exhibit a detectable anisometropia.
b. Infants who exhibit more than 1 D of anisometropia during early infancy almost always
development myopia later in life.
c. If an infant is isometropic (i.e., no anisometropia) at 1 yrs, there is only about a 1 out
of 100 chance that the infant will ever develop a significant anisometropia (e.g., >1.0
D).
d. The prevalence of significant anisometropia (e.g., >1,0 D) increases systematically
from birth to 3 years of age.
e. Anisometropias of about 1-2 D are frequently transient during early development and
not very predictive of the balance of refractive errors later in life.
7. Which of the following ocular dimensions reaches adult-like values earliest in life?
a. corneal power
b. anterior chamber depth
c. lens thickness
d. lens power
e. vitreous chamber depth.
8. For the average individual, which of the following ocular properties are most likely to show
systematic changes between 5 and 10 years of age?
a. axial length and lens power
b. axial length and corneal power
c. vitreous chamber depth and corneal power
d. corneal power and lens power
e. refractive error and axial length.
9. During early infancy (0-3 yrs), the greatest reduction in the eye’s total refracting power comes
about because __________.
a. the cornea gets flatter.
b. the anterior chamber gets deeper.
c. the crystalline lens gets flatter
d. the crystalline lens index decreases
e. the cornea gets flatter and the anterior chamber gets deeper.
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Test A
10. Which of the following statements concerning juvenile onset myopia in the average US
population is NOT correct?
a. The average progression rate is about 0.5 D per year.
b. The onset of myopia is typically between about 8 and 10 years of age.
c. In general, the early the onset of myopia, the higher the rate of progression and the
higher the final degree of myopia.
d. The rate of myopic progression is highly correlated with the rate of axial elongation.
e. None of the above; all the statements are correct.
11. Which of the following predictive statements is NOT correct?
a. Infants who are emmetropic at birth are likely to be myopic at age 3 years.
b. Children who have hyperopic errors greater than +1.5 D at age 6 years will typically
stay hyperopic.
c. Children who have hyperopic error between +0.5 and +1.5 D at age 6 years will
typically become clinically emmetropic.
d. Children who have refractive errors less hyperopic/more myopic than +0.5 at age 6
years will typically become myopic in the next 5-6 years.
e. None of the above; all the statements are correct.
12. Which of the following changes is NOT thought to contribute to the slow refractive error shift
that occurs between the ages 40 and 65 years?
a. a decrease in vitreous chamber
b. an increase in anterior chamber depth
c. the onset of presbyopia
d. an increase in the radius of curvature of the anterior and posterior lens surfaces.
e. an increase in the refractive index of the lens cortex.
13. In a population of young adults, the distribution of ____________.
a. anterior chamber depths is leptokurtic.
b. lens powers is leptokurtic.
c. lens powers conforms to a normal Gaussian distribution.
d. lens powers is flatter than a normal Gaussian distribution.
e. corneal thickness is leptokurtic.
14. Which of the following ocular changes is responsible for the refractive changes in individuals
with early adult onset myopia?
a. an increase in axial length
b. a decrease in anterior chamber depth
c. a decrease in choroidal thickness
d. a decrease in corneal radius
e. an increase in lens power
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Test A
15. Which of the following statements concerning the normal changes in astigmatism that occur
during life is NOT correct?
a. The magnitude of astigmatism measured at 6 months of age is highly correlated with
the astigmatism measured at 6 years of age.
b. On average, the amount of astigmatism increases between birth and 6 months of age.
c. The total refractive astigmatism observed at 6 months of age is highly correlated with
the amount of corneal astigmatism.
d. The changes in astigmatism after 40 years of age occur because the horizontal
meridian of the cornea gets steeper with age at a faster rate than the vertical
meridian.
e. After 40 years of age, the eye develops more against-the-rule / less with-the-rule
astigmatism.
16. Which of the following statements concerning the eyes of identical twins is NOT correct?
a. The refractive errors of monozygotic twins are highly correlated.
b. The similarities between the refractive errors of twins are probably due, at least in
part, to the fact that they usually grow up in the same environment.
c. The between twin correlation for refractive errors is greater for identical twins than it is
for fraternal twins.
d. Although the refractive errors of identical twins are similar, the actual dimensions of
their eyes are usually no more similar than for those for any age-matched pair.
e. The data from identical twins probably provides the strongest evidence that genetic
factors have a substantial affect on refractive development.
17. Based on population statistics, if both parents are myopic, a normal full-term infant is
__________.
a. about 40 to 50 times more likely to become myopic than the offspring of emmetropic
parents.
b. about 4 to 5 times more likely to become myopic than the offspring of emmetropic
parents.
c. more likely show a higher degree of myopia at 4 years of age than at 14 years of age.
d. more likely to exhibit emmetropization during the first 12 months of life than the
offspring of emmetropic parents.
e. more likely to exhibit with-the-rule astigmatism than the offspring of emmetropic
parents.
18. Which of the following statements concerning the phenomenon of form-deprivation myopia
(FDM) is NOT correct?
a. FDM occurs in humans.
b. FDM does not depend on sympathetic input to the eye.
c. FDM occurs even when the optic nerve is surgically sectioned.
d. FDM can occur in both eyes simultaneously.
e. FDM is prevented by surgically eliminating the parasympathetic input to the eye.
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Test A
19. Which of the following statements concerning the effects of moderate powered spectacle
lenses on emmetropization in young monkeys is NOT correct?
a. Infant monkey can alter the relative axial growth rates of the 2 eyes to compensate for
small degrees of anisometropia.
b. Moderate powered lenses that provide clear vision in the unaccommodated state
appear to slow down axial growth.
c. Moderate powered negative lenses accelerate axial growth and promote the
development of myopia.
d. Infant monkeys typically recover from refractive errors produced by spectacle lenses if
unrestricted vision is restored early in life.
e. It is not possible to produce hyperopic refractive error with positive lenses in infant
monkeys.
20. Which of the following statements concerning the role of accommodation in emmetropization
and the development of refractive errors is correct?
a. Studies in monkeys have shown that prolonged accommodation during near work
produces axial myopia.
b. The fact that bifocals slow the progression of myopia demonstrates that
accommodation plays a key role in the genesis of myopia.
c. The fact that the average refractive error becomes more hyperopic with the onset of
presbyopia indicates that accommodation prevents hyperopia and promotes myopia.
d. Accommodation has an indirect effect on refractive development via its influence on
the eye’s retinal image quality.
e. Chronic stimulation of accommodation with pilocarpine results in axial myopia in
monkeys.
21. Which of the following neurotransmitter/neuromodulators analogs does not appear to be
directly involved in the signal cascade that mediates the effects of vision on refractive
development?
a. retinoic acid
b. norepinephrine.
c. dopamine
d. vasoactive intestinal peptide.
e. acetylcholine
22. Which of the following structures/pathways is essential for the development of formdeprivation myopia?
a. retina
b. ciliary body
c. visual cortex
d. Edinger-Westphal Nucleus
e. parasympathetic input to the eye
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Test A
23. Which of the following statements concerning the implications of lens-rearing experiments in
laboratory animals on the phenomenon of emmetropization is NOT correct?
a. The emmetropization process has a limited operating range and refractive errors that
fall outside this range produce unpredictable growth.
b. The eye uses visual feedback associated with the eye’s effective refractive status to
guide ocular growth toward emmetropia.
c. Brief daily periods of unrestricted or clear vision have a stronger effect on eye growth
in young animals than much longer daily periods of either form deprivation or
hyperopic defocus.
d. Emmetropization is dominated by visual signals originating from the fovea.
e. Emmetropization comes about primarily as a result of vision-dependent control over
axial growth.
24. Which of the following statements concerning the effects of visual experience on
emmetropization is NOT correct?
a. The potential for a clear retinal image is essential for normal emmetropization.
b. Form deprivation myopia can be prevented by the topical application of apomorhine.
c. Providing the fovea with clear vision while at the same time producing form
deprivation in the periphery causes the eye to become hyperopic.
d. Although LAISK procedures can correct the optical errors associated with myopia,
these surgical procedures do not reduce the extra risk for retinal detachment
associated with high degrees of myopia.
e. Viewing conditions that have been shown to produce hyperopic growth in young
animals can also produce an increase in the thickness of the choroids.
25. Which of the following statements concerning treatment strategies for myopia is NOT
correct?
a. In terms of reducing the progression of myopia, recent studies have shown that
progressive addition lenses produce larger effect in exophoric individuals.
b. Topically applied anti-glaucoma drugs that reduce intraocular pressure do not prevent
or slow down the progression of myopia.
c. Topically applied atropine slows the progression of myopia via a non-accommodative
mechanism.
d. Pirenzepine is a relatively selective cholinergic muscarinic antagonist that has been
shown to slow the progression of juvenile onset myopia in a dose dependent fashion.
e. There is little evidence that prescribing base-in prism for near work reduces the
progression of juvenile onset myopia.
26. Experiments in laboratory animals suggest that _____________.
a. form deprivation can produce myopia in adolescent animals but that hyperopic optical
defocus can only produce myopia during the rapid period of emmetropization.
b. once the eye has reached its adult axial length form deprivation can not produce
myopia.
c. both form deprivation and hyperopic optical defocus can produce myopia in
adolescent animals.
d. in adolescent animals myopic defocus can produce hyperopic shifts in refractive error.
e. hyperopic defocus can produce myopia in adolescent animals but form deprivation
does not affect refractive development.
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Test A
27. Which of the following statements concerning the temporal integration properties of the
mechanisms that mediate vision-dependent eye growth are NOT correct?
a. Brief daily periods of unrestricted vision can counteract the myopiagenic effects of
much longer daily periods of form deprivation.
b. As long as infants wear spectacle lenses for at least 50% of the daily lighting cycle,
positive lenses will predictably produce hyperopic shifts in refractive error.
c. Multiple daily periods of unrestricted vision are more effective in preventing myopia in
response to form deprivation or hyperopic defocus than a single daily period of
unrestricted vision
d. The way in which the mechanisms that mediate vision-dependent eye growth
integrate the effects visual experience normally reduces the likelihood that the eye will
become myopic.
e. Because the mechanisms that mediate vision dependent growth integrate visual
experience over time in a non-linear way, the use of “diopters-hours” to quantify the
amount of near work is probably not the optimal measure.
28. Which of the following ocular components are distributed randomly in a population of young
adults? (i.e., which components conform to a normal Gaussian distribution)
a. corneal power
b. lens power
c. anterior chamber depth
d. a and b
e. all of the above
29. The increase in the depth of the anterior chamber during the early school years (i.e, during
the slower juvenile phase of ocular growth) can be attributed ___________.
a. primarily to a decrease crystalline lens thickness
b. to a backward displacement of the lens into the vitreous chamber
c. to a steepening of the corneal curvature resulting in a forward displacement of the
corneal apex.
d. all of the above
e. none of the above.
30. In comparison to emmetropic eyes, typical myopic eyes are more likely to develop
___________.
a. nuclear cataracts
b. angle closure glaucoma
c. peripheral corneal dystrophies
d. chorioretinal degeneration
e. all of the above are correct.
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