When light is refraction by a prism it is:
a. Bent toward the apex
b, Bent toward the base
c. Not bent
d. Reflected - correct answer B. Bent toward
... [Show More] the base
A prism always bends light toward its base.
Prisms:
I. Always bend light toward the base
II. Always bend light toward the apex
III. Cause chromatic Dispersion
IV. Move the image toward the apex
V. Are sometimes prescribed for muscle problems - correct answer I. Always bend light toward base
III. Cause chromatic dispersion.
IV. Move the image toward the apex.
V. are sometimes prescribed for muscle problems
Plus lenses are:
I. are thicker in the center than at the edges
II. Are used to correct myopia
III. Are used by all presbyopes
IV. Must be surfaced individually in the laboratory - correct answer I. Are thicker in the center than at the edges.
Which of the following does not describe a minus lens
a, The image moves with motion
b. Thicker at the edge than in the center
c. Magnifies the image
d. Corrects for myopia - correct answer c. A minus lens minifies, not maginfies
The parts of the eye that refract light are:
a. Cornea, Aqueous humor, lens and vitreous humor
b. Cornea, Iris, and lens
c.Retina, choriod, lens, and aqueous humor
d. cornea, lens, and pupil - correct answer A. Cornea, Aqueous humor, lens and vitreous humor.
Where the sclera and the cornea meet is called the
a. Iris
b. Limbus
c. Ora serrata
d. conjunctiva - correct answer B. Limbus
A cataract is:
a. A film over the eye
b. a cloudiness of the crystalline lens
c. removal of the crystalline lens
d. an internal ptergium - correct answer b. A cloudiness of the crystalline lens
A cataract may also be referred to as opacification of the lens. removal or absence of the crystalline lens is aphakia
Near visual acuity is often abbreviated as:
a. 20/40
b. 10/10
c. N. 15
d. J.2 - correct answer D. J.2
Distance visual acuity usually has two numbers. It is a comparison of the distance a patient is from the target to what an average person can see at that distance. One of the most common tests for visual acuity is the Jaeger test Card. The results are signified by the letter J with a number.
Myopia can be attributed to
a. Loss of accommodation.
b a shorter than normal eyeball
c. a longer than normal eyeball
d. astigmatism - correct answer C. a longer than normal eyeball
Myopia is a condition of distance vision. It is caused by the refracting system of the eye having too much plus power for length, or the eye being too long for its power.
Eyeglasses can relieve or correct all of the following conditions except:
a. A scotoma
b. Presbyopia
c. Simple astigmatism
d. Mixed astigmatism - correct answer a. A scotoma
A scotoma is a "blind spot" of the retina. no glasses can correct it.
The condition known as second sight is often associated with:
a. increase in accommodation
b. incipient cataract
c. ocular rejuvenation
d. surgery - correct answer b. Incipient cataract.
Some presbyopes find they no longer need glasses to read. This so called "Second sight" is usually caused by an increase in myopia due to swelling of the crystalline lens caused by a developing cataract.
A aphakic patient is more sensitive to light because
a. the filtering action of the crystalline lens is no longer present
b. cataract surgery often results in ptosis
c. of the age of the patient
d. proper fitting reduces vertex power. - correct answer A. the filtering action of the crystalline lens is no longer present
A Crystalline lens is a very effect filter for ultraviolet light, and as the patient gets older visible light at the short end of the spectrum (especially blue). When the lens is removed (cataract surgery) the person is often very sensitive to light. A ptosis or drooping of the lid is often present after surgery, but this will only reduce the amount of light entering the eye.
With new glasses, a patient complains that things appear smaller. this could be caused by
a. increase in plus power
b. increase in minus power
c. decrease in minus power
d. astigmatism is uncorrected - correct answer b. Increase in minus power
minus lenses minify the image (make things smaller)
A person with diplopia:
a. sees only one half of an object
b. sees two objects
c. sees objects divided
d. has low visual acuity - correct answer b. Sees two objects
Di=two; diplopia= double vision
OD +2.00 +.50 x 90
OS +0.50 +0.25 x85
The above prescription illustrates a case of:
a. Presbyopia
b. anisometropia
c. antimetropia
d. simple myopic astigmatism - correct answer B. Anisometropia [Show Less]