chapter 10 prism Flashcards
light rays are deviated towards the ____ of the prism, the image is displaces towards the ___ of the prism
a. apex, base
b. base, apex
c. apex, apex
d. base, base
B
as apical angle increases, the angle of deviation and prismatic power _________
a. increase
b. decrease
c. stays the same
A
an apical angle of a prism is only considered a thin lens when the angle is _____
a. greater than 10 degrees
b. less than 10 degrees
c. equal to 10 degrees
d. greater than 15 degrees
e. less than 10 degrees
B
when considering lenses, a vergence change of incoming ray gives what type of power ?
a. prismatic
b. dioptric
A. dioptric
when considering lenses, a change in direction of incident light gives what type of power?
a. prismatic
b. dioptric
A. Prismatic
if a meridian has no lens power, what is the prism power ?
a. always 1
b. identical to the opposite meridian
c. always zero
C
which type of bifocal is more likely to experience bifocal jump ?
a. round bifocal
b. flat top bifocal
c. square bifocal
c. none of the above
A
what factors increase the chances of bifocal jump?
a. increasing distance from the ADDs optical center to the top of lens
b. decreasing distance from the ADDs optical center to the top of lens
c. both A and B
d. none of the above
A
does bifocal jump alone cause vertical imbalance when the add power is identical OU
a. yes
b. no
B
if an a plus lens moved down, the image you see through the lens would be
a. upwards
b. downwards
c. left
d. right
A. upwards
plus lenses undergo against motion
if a minus lens moved upwards, the image you see through the lens would be
a. upwards
b. downwards
c. left
d. right
A
if the rotation of the lens does not results in rotation of the cross view through the lens, what type of lens does this represent ?
a. spherocylindrical
b. prism
c. spherical
d. progressive
C
if the lens is rotated clockwise, the vertical line rotates in the direction of the lens, what type of lens does this represent ?
a. spherocylindrical
b. prism
c. spherical
d. progressive
A
if a clockwise rotation of the lens causes a limb of the cross seen through the lens to rotate in the same direction as the lens, the meridian of alignment is ____
a. spherical
b. Plus axis
c. Minus axis
C
if rotation of the lens causes a limb of the cross seen through the lens to rotate in the opposite direction, the meridian of alignment is the ____
a. spherical
b. Plus axis
c. Minus axis
B
