Presbyopia and Multifocals Flashcards

1
Q

The ability of the eye to variably focus is known as what?

A

Accommodation

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2
Q

Which structure of the eye provides it with variable focusing capability?

A

Crystalline lens

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3
Q

How much accommodative ability does the average person have at birth?

A

15.00 D

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4
Q

What is the definition of presbyopia?

A

The inability to see near objects clearly and comfortably

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5
Q

As a person ages, their near point does what?

A

Recedes

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6
Q

What percentage of the US population was estimated to become presbyopic by the year 2020?

A

42%

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7
Q

According to US Census data projected to 2050, which is the only age group that will show an increase in number?

A

55+

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8
Q

What percentage of the current US population over 55 needs eyewear?

A

84%

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9
Q

As a practicing optician, your role with presbyopic patients will be to determine their lifestyle needs and wants in order to do what?

A

Match product features and benefits to them

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10
Q

What was the earliest form of presbyopic lens correction?

A

Single vision lenses - readers

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11
Q

Who is attributed with the concept of correcting presbyopia with bifocals?

A

Benjamin Franklin

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12
Q

What was the design of the first bifocal lens?

A

Two differently powered halves secured in the same eyewire

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13
Q

What was a problem that was not associated with August Morck’s cemented bifocal lenses?

A

The different indices between the distance lens and the wafer lens caused color aberration for the wearer

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14
Q

What was the name of the glass bifocal lens design that was the first to use a fusing process?

A

The Kryptok

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15
Q

Which bifocal lens exhibited color aberration for the wearer through the segment?

A

Kryptok

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16
Q

When was the first trifocal lens developed?

A

1936

17
Q

What is the furthest and closest a person will be able to see if he is looking through a plano distance, +2.50 add multifocal and has 4.00D of accommodative amplitude?

A

40cm to 15.4cm

18
Q

For a specified distance rx power, what happens to the ranges of clear vision through a segmented multifocal as add powers get high?

A

The zones shrink

19
Q

What is a significant indication of the “Ranges of Clear Vision Through Multifocals” chart?

A

Fixed power zone segmented lenses may not be the best way to correct presbyopia

20
Q

Why did progressives take so long to enter the marketplace from the time they were first theorized?

A

The technology needed to produce them was not available

21
Q

The blended region between the distance and near zones of a progressive addition is known as the _____ zone.

A

Intermediate

22
Q

When a lens has its surface astigmatism concentrated into smaller areas of the lens, it is classified as _____ design

A

hard

23
Q

Which progressive lens design classification do most manufacturers use?

A

A combination of hard and soft

24
Q

Who designed the first progressive addition lens?

A

Bernard Maitenaz

25
Q

How did the original Varilux lens use aspheric power?

A

It used all its progressive power in 12mm

26
Q

How did the Varilux II lens use aspheric power?

A

The lens was completely progressive from top to bottom

27
Q

Which progressive addition lens was the first to employ true right and left blanks?

A

Varilux

28
Q

What is the advantage of using multi-design for progressive addition lenses?

A

The lens design changes as add power increases based on the intended needs of the wearer as they age

29
Q

Define asymmetrical design in progressive lenses

A

There is more surface astigmatism in one side of the lens than then other and/or the areas of surface astigmatism are not equal

30
Q

What is the advantage of a short corridor progressive lens design?

A

It allows the use of a shallow B measurement frame

31
Q

What is the best method for assessing the potential success of a progressive addition lens?

A

Wearer trials

32
Q

All early progressive addition lenses were designed for what?

A

General use

33
Q

What is the name of the software files used by direct-to-surface (free-form) generators?

A

Point files

34
Q

Why should you have the lens markings on a progressive lens at the time of delivery adjustment?

A

So you can accurately align the fitting cross with the pupil center