Download Vision Science II - Visual Optics Institute

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Vision Science II
Opto 5221
April 23, 2003
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 principal plane or ocular refractive
errors. Use Emsley’s reduced eye model for all calculations. RSM=relative spectacle
magnification; SM=spectacle magnification.
1. In comparison to a normal Gaussian distribution, the distribution of spherical equivalent refractive
errors for a random sample of the young adults in the USA is:
a. 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).
b. 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).
c. leptokurtic with fewer clinical emmetropes, more individuals with moderate refractive errors
(e.g., -3.0 D), and few individuals with larger refractive errors (>+6.0 D).
d. platykurtic with fewer clinical emmetropes, fewer individuals with moderate refractive errors
(e.g., -3.0 D), and more individuals with larger refractive errors (>+6.0 D).
e. 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).
2. At which of the following ages does the distribution of spherical equivalent refractive errors mostly
closely conform to a random distribution?
a. at birth (full-term infants)
b. 3 years
c. 8-10 years
d. 40 years
e. 60-70 years
3. With respect to spherical equivalent refractive errors, at which of the following ages would you
expect to find the smallest variance in the population of “normal” individuals?
a. at birth (full-term infants)
b. 3 years
c. 20 years
d. 40 years
e. 60 years
4. Which of the following age groups would include the greatest proportion of myopic individuals
(assume a US population)?
a. 8-10 years
b. 3-6 years
c. premature infants weighing less than 1500 grams
d. 20-30 years
e. 60-70 years
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5. What is the most common age for the onset of common axial myopia in the US population?
a. 3-6 years
b. 8-10 years
c. 14-18 years
d. 20-30 years
e. after 65-70 years
6. Which of the following parts of the eye reach adult-like dimensions at the earliest age?
a. axial length
b. vitreous chamber depth
c. crystalline lens
d. anterior chamber depth
e. cornea
7. Myopia is almost always associated with an increase in axial length. However, at which of the
following ages is the incidence of myopia or relative myopic shifts in refractive error likely to
be due to factors other than axial length?
a. full-term neonates and children 14-18 years old
b. full-term neonates and individuals 40-60 years of age
c. premature infants and individuals 40-60 years of age
d. premature infants and individuals >65 years of age
e. premature infants and individuals 2-30 years of age.
8. With respect to the development of myopia, which of the following statements is NOT correct?
a. In general, the earlier the onset of myopia, the faster the annual rate of progression.
b. In general, the earlier the onset of myopia, the higher the final degree of myopia.
c. For many individuals, myopic progression stops in late teenage years when axial growth
normally stops.
d. The annual rate of myopic progression in US children is typically about 0.25 D per year.
e. Children of two myopic parents are about 5 times more likely to become myopic than children
of non-myopic parents.
9. Which of the following factors are thought to contribute to the normal shift toward hyperopia (or less
myopia) that occurs beginning at about 40-45 years of age?
a. the onset of presbyopia, a flattening of the crystalline lens, an increase in the refractive index
of the crystalline lens cortex, and possibly a decrease in vitreous chamber depth.
b. a flattening of the crystalline lens, an increase in the refractive index of the crystalline lens
cortex, and possibly a decrease in vitreous chamber depth.
c. the onset of presbyopia, a flattening of the crystalline lens, a decrease in the refractive index
of the crystalline lens cortex, and possibly a decrease in vitreous chamber depth.
d. the onset of presbyopia, a flattening of the crystalline lens, and possibly a decrease in
vitreous chamber depth.
e. the onset of presbyopia, an increase in the refractive index of the crystalline lens cortex, and
possibly a decrease in vitreous chamber depth.
10. Which of the following statements concerning astigmatism is NOT correct?
a. In a young adult population, astigmatism is the most common ametropia.
b. During infancy the prevalence of astigmatism is highest at about 10 weeks of age.
c. The amount of astigmatism measured at 20 years of age is highly correlated with the amount
of astigmatism that an individual had during the first year of life.
d. The astigmatism found during infancy is associated with corneal toricity.
e. Although there has been some controversy concerning the axis of early astigmatism, the
more recent studies have indicated that infants typically exhibit with-the-rule astigmatism.
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11. Which of the following statements concerning the changes in astigmatism that occur in the average
individual after the age of about 40 years is correct? (ATR = against-the-Rule; WTR = withthe rule)
a. The astigmatic error shifts toward ATR and away from WTR because the vertical meridian of
the cornea gets flatter.
b. The astigmatic error shifts toward ATR and away from WTR because the horizontal meridian
steepens at a faster rate than the vertical meridian.
c. The astigmatic error shifts toward WTR and away from ATR because the vertical meridian
steepens at a faster rate than the horizontal meridian.
d. The astigmatic error shifts toward WTR and away from ATR because the horizontal meridian
of the cornea gets flatter.
e. The astigmatic error shifts toward ATR and away from WTR because the horizontal meridian
flattens at a faster rate than the vertical meridian.
12. Which of the following statements concerning the shape of emmetropic eyes of young adults is
correct?
a. Corneal power is usually positively correlated with crystalline lens power.
b. Corneal power is usually negatively correlated with axial length.
c. Crystalline lens power is usually negatively correlated with axial length.
d. Crystalline lens power is usually negatively correlated with corneal power.
e. There are no significant correlations between individual ocular components in emmetropic
eyes.
13. 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. Although the refractive errors of identical times are similar, the actual dimensions of their
eyes are usually no more similar than for those for any age-matched pair.
c. The between twin correlation for refractive errors is greater for identical twins than it is for
fraternal twins.
d. 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.
e. The data from identical twins probably provides the strongest evidence that genetic factors
have a substantial affect on refractive development.
14. Which of the following statements concerning the phenomenon of form-deprivation myopia (FDM)
is NOT correct?
a. The magnitude of FDM depends primarily on the age of onset and is not influenced by the
degree of image degradation.
b. FDM occurs in humans and the mechanisms responsible for FDM in human eyes are
probably very similar to those in the eyes of chickens.
c. The mechanisms that mediate FDM are largely independent in the two eyes.
d. FDM occurs primarily as a result of an increase in vitreous chamber depth.
e. Early in life animals can recover from FDM if unrestricted vision is restored.
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15. 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 eye uses visual feedback associated with the eye’s effective refractive status to guide
ocular growth toward emmetropia.
b. The emmetropization process has a limited operating range and refractive errors that fall
outside this range produce unpredictable growth.
c. Emmetropization comes about primarily as a result of vision-dependent control over axial
growth.
d. The mechanisms responsible for vision-dependent emmetropization are only active during
the rapid infantile phase of ocular growth.
e. Although animal experiments suggest that hyperopic defocus should produce axial myopia,
there is little evidence from clinical studies that “overminusing” children will result in faster
myopic progression rates.
16. 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.
17. What is the most likely explanation for the failure to see dramatic evidence that wearing spectacle
lenses can alter refractive development in young children?
a. The mechanisms that regulate eye growth in young children are qualitatively different from
the growth-regulating mechanisms in common laboratory animals.
b. The available clinical data are from children who are too old.
c. Brief daily interruptions in lens wear probably reduce the effects of the spectacle lenses on
eye growth.
d. a and c are correct
e. all of the above are correct
18. 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. A single daily period of unrestricted vision is probably more effective in preventing myopia in
response to form deprivation or hyperopic defocus than multiple daily periods of unrestricted
vision.
c. The ability of brief daily periods of unrestricted vision to prevent experimental myopia is
quantitatively similar in chickens and monkeys.
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.
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19. One of the most important clinical implications of the phenomenon of form-deprivation myopia is
that ______________.
a. the potential for a clear retinal image is essential for normal emmetropization.
b. all types of optical defocus produce myopia.
c. accommodation plays a critical role in late-onset or early adult onset myopia.
d. genetic factors have little impact on refractive development.
e. males are more susceptible to the effects of near work than females.
20. Which of the following conditions are least likely to be an ocular sequelae of axial myopia?
a. open-angle glaucoma
b. idiopathic retinal detachment
c. posterior supcapsular cataract
d. chorioretinal degeneration
e. presbyopia
21. With respect to the consequences of the many ocular complications associated myopia, which of
the following statements is NOT correct?
a. Myopia is the 7th leading cause of legal blindness in the US.
b. Myopia below -3.0 to -4.0 D is not a risk factor for ocular morbidity.
c. Refractive surgery for myopia does not reduce the risk of ocular morbidity.
d. Myopic retinal degeneration is the second highest cause of low vision in Asia.
e. Of the leading causes for legal blindness in the US, myopia falls just behind diabetes in
terms of putting one a risk for vision disability.
22. Which of the following statements concerning the role of near work in the genesis of myopia is
NOT correct?
a. Many traditional therapies for preventing myopia were based on the premise that something
about the physical act of doing near work promoted the development axial myopia.
b. Many early myopia therapies were based on the premise that near work resulted in an
increase in intraocular pressure, which caused axial myopia.
c. Some early myopia therapies were based on the notion that during convergence for near
objects, the extraocular muscles exerted physical forces on the eye that promoted axial
myopia.
d. It has been argued that reading with a face down posture produces myopia via the competing
actions of gravity pulling the eye down and the optic nerve holding the eye up.
e. Recent experiments have shown that progressing myopes actually accommodate more than
non-myopes when performing near work.
23. Which of the following statements concerning the effects of bifocals on the progression of myopia
is NOT correct?
a. In general, most studies have shown that bifocals produce a small, but statistically significant
reduction in the progression rate of myopia.
b. Bifocals are most effective in reducing the progression of myopia in individuals who are
exophoric at near.
c. The therapeutic effects of bifocals are associated with reductions in the axial growth rates.
d. In multi-year studies, it appears that the benefits of bifocals occur primarily in the first year of
treatment.
e. Progressive addition bifocals are not necessarily better than traditional bifocals in reducing
myopic progression rates.
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24. Studies in animals and humans have shown that topically applied timolol ______________.
a. can reduce IOP in both humans and animals but it does not slow the progression of myopia.
b. can reduce the IOP in humans but not in animals.
c. can slow the progression of form-deprivation myopia in birds but not in humans.
d. can eliminate accommodation in birds without reducing IOP.
e. can slow the progression of myopia without lowering IOP.
25. Topically applied atropine has been shown to ___________________.
a. have many short-term side effects, but there is no evidence that prolonged atropinzation can
have permanent effects on the developing eye.
b. reduce the progression of myopia via the drug’s action on pupil size.
c. reduce the progression of myopia in humans and to prevent form-deprivation myopia in
animals.
d. reduce the progression of myopia via the drug’s action on the pupil.
e. to increase the progression of myopia because chronic mydriasis reduces the quality of the
retinal image.
26. Which of the following manipulations have been shown to prevent the myopia produced by
monocular form-deprivation in laboratory animals?
a. surgically removing the primary visual cortex.
b. cutting the optic nerve of the deprived eye.
c. cutting the optic nerve of the non-treated eye.
d. surgically eliminating the primary sympathetic and parasympathetic inputs to the deprived
eye.
e. none of the above
27. Based on recent experiments involving laboratory animals, which of the following statements
concerning the vision-dependent mechanisms that mediate eye growth is NOT correct.
a. Selectively depriving a portion of the retina of a clear retinal image restricts the axial
elongation and myopia to the deprived area.
b. The mechanisms that mediate the effects of visual experience on eye growth are located
largely within the eye.
c. Although visual experience can alter choroidal blood flow, the thickness of the choroid is
unaffected by visual experience,
d. Accommodation, by its influence on retinal image quality, plays an indirect role in
emmetropization.
28. Pirenzepine is a __________________________.
a. relatively selective nicotinic, cholinergic receptor blocker that acts primarily at the M3
muscarinic receptor.
b. unselective muscarinic, cholindergic receptor blocker that acts equal on all muscarinic
receptors.
c. relatively selective muscarinic, cholinergic receptor blocker that acts primarily at the M1
muscarinic receptor.
d. relatively selective muscarinic, cholinergic receptor blocker that produces a mild cycloplegia
via its actions on the M4 muscarinic receptor.
e. relatively selective muscarinic, cholinergic receptor blocker that produces mild pupil dilation
primarily via its actions on the M1 muscarinic receptor.
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29. FDA approved clinical trials in humans suggest that ___________________.
a. 2% pirenzepine gel applied topically to the eye twice each day has no effects of pupil size.
b. 0.5% pirenzepine gel applied topically to the eye once each day reduces the myopic
progression rate in children by 70%.
c. topically applied 2% pirenzepine gel failed to reduce myopic progression in children in a
clinically significant manner.
d. 2% pirenzepine gel applied topically to the eye twice each day reduces the myopic
progression rates in children by about 50%.
e. 2% pirenzepine gel applied topically to the eye twice each day reduces the amplitude of
accommodation by about 50%.
30. Based on experiments involving form deprivation myopia in laboratory animals, which of the
following statements is NOT correct?
a. Form deprivation decreases the amount of dopamine in the retina.
b. Form deprivation myopia can be prevented by the topical application of the dopamine
agonist, apomorhine.
c. Form deprivation myopia can be prevented by topically applying antagonists to vasoactive
intestinal peptide.
d. Haloperidol is a selective D2 dopamine receptor blocker that when applied to the eye
prevents form-deprivation myopia.
e. Early gene expression in glucagon containing amacrine cells is influenced in a complimentary
way by hyperopic versus myopic defocus.
31. Which of the following substances has been implicated as a possible choroidal signal messenger in
the biochemical cascade that regulates eye growth?
a. ZENK
b. glucagon
c. acetylcholine
d. retinoic acid
e. matrix metalloproteinase
32. Which of the following changes does NOT take place in mammalian sclera during the development
of form-deprviation myopia?
a. There is a decrease in proteoglycan synthesis.
b. Gelatinolytic enzymes increase the amount catabolic acitivity in the sclera.
c. There is an increase in amount of MMP-2 activity in the sclera.
d. The extensibility or creep rate of the sclera increases
e. The sclera grows and gets thicker.
33. In a young adult population, the frequency distribution for _____________.
a. corneal power conforms to a normal Gaussian distribution.
b. anterior chamber depth is flatter than a normal Gaussian distribution.
c. crystalline lens power is more peaked than a normal Gaussian distribution.
d. axial length is flatter than a normal Gaussian distribution.
e. crystalline lens power is flatter than a normal Gaussian distribution.
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