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BOARDS2: Ophthalmic Optics > ANSI > Flashcards

ANSI Flashcards

1
Q

occupation and glasses

A

it is important to know the patients occupation when fitting them for glasses

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2
Q

normal pantoscopic tilt

A

7 degrees

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3
Q

how does panto change glasses Rx

A

its rotated around 180 degrees

  • induces minus cyl at 180
  • induced plus cyl at 180
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4
Q

how does faceform change glasses RX

A

lens tilted around the 90 axis

  • induces minus cyl at 90
  • induces plus cyl at 90
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5
Q

how does panto affect the sphere component of glassed

A

increase the plus and the minus sphere

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6
Q

panto and PALs

A

patients who wear PALs benefit from panto because it moves the reading portion of the lens closer to the eye, which increased the reading width of the lens

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7
Q

how much does the OC lower when there is added panto

A

for every 2 degrees of panto, the OC is lowered 1mm

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8
Q

panto and lens distortion

A

will typically increase and alter the cylindrical effect

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9
Q

how to induce panto

A

adjusting the angle of the temple

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10
Q

retroscopoc tilt

A

causes the top of the lens to be close to the face

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11
Q

pantoscopic tilt is helpful if the optical center of the lens is too ____

A

high

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12
Q

ANSI standard for horizontal prism

A

2/3 amount prism

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13
Q

ANSI standard for vertical prism

A

1/3 amount of the prism

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14
Q

ANSI : sphere -6.50 to +6.50

A

+/- 0.13

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15
Q

ANSI: sphere >+/-6.50

A

+/- 2% sphere power

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16
Q

ANSI: cyl <2.00D

A

+/-0.13

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17
Q

ANSI: cyl 2.00-4.50D

A

+/- 0.15

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18
Q

ANSI: cyl >4.50D

A

4% of cyl power

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19
Q

ANSI: cyl axis 0.25 or less

A

+/-14

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20
Q

ANSI: cyl axis >0/25-0.50

A

+/-7

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21
Q

ANSI: cyl axis >0.50-0.75

A

+/-5

22
Q

ANSI: cyl axis 0.75-1.50

A

+/-3

23
Q

ANSI: cyl; axis 1.50

A

+/-2

24
Q

how to lower the height of the bifocal segment

A

the glasses need to be lowered on the patients face

increase the distance between the nosepads
raise the vertical portion of the nosepads
widen the bridge of the frame

25
Q

glasses falling down face

A

pull in temple
bend down temple tips
pull in nosepads to tighten the fit

26
Q

one lens feels closer to the face than the other lens

A

straighten the temples

27
Q

glasses touching cheeks

A

reduce panto
narrow bridge or nosepads to raise frame
narrow bridge or nosepads to increase vertex distance

28
Q

glasses to close to face

A

narrow the nosepads, shrink the bridge, or decrease faceform to move lenses away from face

29
Q

frames sit sit too low on the face

A

narrow the bridge, add nosepads, or lower vertical position of pads to move frames up on face

30
Q

if the frame is too high on one side

A

bend temples toward the problem

31
Q

if the segment is too high

A 
increased panto
decrease the vertex distance 
spread the nosepads
move the nosepads up by adjusting the notepad arms 
stretch the bridge
32
Q

if the segment is too low

A 
narrow the nosepads
move the nosepads down by adjusting the notepad arms
increase the vertex distance
reduce panto tilt
shrink the bridge
33
Q

abbe value and aberration

A

increased abbe value=decreased aberration

34
Q

abbe value of diff lens materials

A 
crown:58.9
CR-39: 58
Trivex: 44
high index: 40
polycarbonate: 30
35
Q

pros of crown glass

A

does not scratch

36
Q

cons of crown glass

A

heavy, shatters

37
Q

pros of CR-39

A

light

38
Q

cons of CR39

A

scratches easily

39
Q

pros of polycarbonate

A

safety

40
Q

cons of polycarbonate

A

high chomratic aberration, scratches

41
Q

pros of high index

A

very thin and light

42
Q

cons of high index

A

high chromatic aberrations, scratches

43
Q

pros of trivex

A

safety, less chromatic aberration

44
Q

cons of trivex

A

thicker than poly, more expensive

45
Q

what powers need aspheric lenses

A

-23 and higher

+7 and higher

46
Q

best frames and lenses for high myopia

A
  • small eye and larger bridge
  • round shape frame
  • high index lenses
  • roll and polish lens edges
  • aspheric lenses
47
Q

best frames and lenses for high hyperopia/aphakia

A
  • small eye size (induced prism if too large)
  • round shape frmae
  • high index lenses
  • cable temples
  • apsheric lenses
48
Q

Best frame and lens options for PALs

A
  • adequate panto tilt
  • adequate vertical depth and nasal portion
  • minimal vertex distance
49
Q

best frames and lenses for kids

A
  • polycarb lenses for safety
  • sturdy frame
  • consider transitions
  • eye protection for sports
  • spring temples
  • no rimless frames
50
Q

safety regulations of lenses

A

Z87

  • 5/8 inch diameter steel ball dropped from 50”
  • safety glasses: the steel ball is increased to 1” diameter for testing from the same distance
  • the marking for safety lenses is Z87
  • RX lenses must have a minimum thickness of 3mm, except for plus lenses >3D
51
Q

who should get polycarbonate lenses

A

all children, monocular patients, and patients using glasses for safety or sports

52
Q

double D bifocal

A

lined bifocal at the bottom of the lens and at the top of the lens. it is an occupational lens that is most often RXed for patients who perform detailed work above their line of sight, such as electricians and auto mechanics

BOARDS2: Ophthalmic Optics (3 decks)

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