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Optical Dispensing year 2 > Unit 1 > Flashcards

Unit 1 Flashcards

1
Q

Lens types

A

-CR-39
-Trivex
-Polycarbonate
-Mid-index
-High-index
-Aspheric
-Glass

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2
Q

CR-39 index

A

1.498

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3
Q

Trivex index

A

1.530

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4
Q

Poly index

A

1.586

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5
Q

Mid-index index

A

1.6 or 1.57

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6
Q

High index index

A

1.67

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7
Q

Aspheric index

A

1.61 or 1.67 or 1.74

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8
Q

Glass index

A

1.523

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9
Q

Base curve formula

A

F1 + F2 = FT

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10
Q

Approximate formula

A

F0= Fsph + Fcyl (Sin 0) ^2

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11
Q

How do you know if there is prism in lens?

A

-When looking in lensometer the lines inside cannot be centered
-When PD and OC is off and doesnt match the order
-When you move the frame table in between OD and OS lens

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12
Q

How to measure verticle prism in lensometer?

A

-You need to know where the person is looking through and mark it
-Put the mark spot on the eye piece of lensometer
-Note down where the illuminated target is positioned, compare the two

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13
Q

How was the first bifocal made in early 20th century

A

-A cemented wafer was the first bifocal made
-The bifocal was a reading ADD cemented on to the distance power
-Introduced by AO (american optical) in the mid 1880s

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14
Q

When was cemented wafer made?

A

1880

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15
Q

When was ultex made?

A

1917 - semi circle (inside of lens not outside)

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16
Q

When was Tillyer ful vue made

A

1925 (round style bifocal , OC is at top)

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17
Q

When was panoptik made

A

1929 - (sold under licnesed, fused glass bifocal )

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18
Q

When was kyrptok made

A

1935

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19
Q

When was executive made

A

1952 (distance on top reading on bottom , 2 rounds lenses)

20
Q

When was blended made

A

1978 - bifocal with no line

21
Q

Aspheric lenses

A

-Thinner
-Lighter
-Flatter
-Be careful with minus lenses
-Less magnified eyes

22
Q

Atoric lenses

A

-Essentially it is an aspheric lens compensating for cylinder as well
-Atoric is flattening the cylinder curve
-Use an atoric if the cyl is more than -2.00

23
Q

Image jump can happen in what lenses?

A

Round bifocal
Flat top bifocal

24
Q

Calculating image jump

A

-You will be given width, depth and power
-Divide the width in half, take the half od the width and subtract it from the depth. Take whatever you get from the depth, divide that in 10 and multiply it by the rx given.

25
Q

Where is distortion in a PAL lens?

A

Peripheral vision because we dont look in those areas as much

26
Q

Hard design

A

Full width distance portion, very narrow intermeidate coridor and a wide reading area, wilder field of view

27
Q

Soft design

A

A wide intermediate portion at the expense of distance and near zones

28
Q

What measurments are taken for Individualized lenses (Free form)

A

Pantoscopic tilt
Frame wrap
Vertex distance
Optical Centre
Monocular PDS

29
Q

Miyosmart lenses

A

Slows the progression of myopia by allowing the px to see clearly through the centre and the outsides are blurry allowing for them to focus through one specific area

30
Q

Myodisc lens

A

A lenticular type of lens that corrects for a high minus astigmatism

31
Q

What happened in 1907

A

Owen patended a dual service progressive lens

32
Q

what happened in 1909

A

henry owford created another one but it failed

33
Q

what happened in 1911

A

george pollain and julian corne failed

34
Q

what happened in 1959

A

bernard first progressive lens that actually worked

35
Q

what happened in 1962

A

bought them patended - called it SL

36
Q

what happened in 1976

A

plastic came out

37
Q

what happened in 1981

A

gerhard further worked for carl zeiss and developed the free form progressive lensews

38
Q

A glass bifocal that was created by using a higher index of refraction for the add power.

A

fused bifocal

39
Q

A lens created to achieve the most natural transition between different distances.

A

freeform progressive lenses

40
Q

A bifocal that places the near optical centre at a comfortable position for close work, reducing the amount of image jump when moving between distance and near vision.

A

ful-vue bifocal

41
Q

A bifocal with the optical centre placed at the top of the segment.

A

executive bifocal

42
Q

A multifocal lens created by Benjamin Franklin.

A

exective bifocal

43
Q

All bifocals in this lens material are created by changing the front curve of the lens.

A

CR-39

44
Q

In 1978, a bifocal was created that was considered the start of progressive lenses for American Optical.

A

BLENDED BIFOCAL

45
Q

A multifocal lens created by Bernard Maintenanze.

A

Progressive add lens (pal)

46
Q

A bifocal with the segment attached to the concave side of the lens.

A

ultex

47
Q
A

Optical Dispensing year 2 (3 decks)

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