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Vision Science 4 Dr. Drescher > Lec.1 Ultraviolet Radiation & Nonprescription > Flashcards

Lec.1 Ultraviolet Radiation & Nonprescription Flashcards

1
Q

Based on the AOA 2013 American Eye-Q Survey:
___% of americans wear sunglasses to safeguard vision from sun damage.
___% used sunglasses for comfort and reduction of glare.
___% said UC protection is the most important factor when purchasing sunglasses.

A

40, 32, 28

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2
Q

Electromagnetic spectrum for ultraviolet is _____nm.

A

100-400

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3
Q

Electromagnetic spectrum for visible spectrum is _____nm.

A

400-700

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4
Q

Electromagnetic spectrum for infrared spectrum is ____.

A

760nm-1mm

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5
Q
  1. UV-A is ____nm.
  2. UV-B is ____nm.
  3. UV-C is ____nm.

a. 100 - 290
b. 290 - 320
c. 320 - 400

A
  1. c
  2. b
  3. a
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6
Q

Peripheral Light-focusing (PFL) can create areas of concentrated light in the ______ and _______.

A

nasal corneal limbus, lens cortex

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7
Q

T/F PLF may be implicated in pterygium and age-related cortical cataracts.

A

True

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8
Q

Intensity of light reaching the nasal limbus reaches levels __X higher than the intensity of temporally incident light.

A

20

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9
Q

Peak effect for UV-A and UV-B is about ___degrees behind the frontal plane.

A

120

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10
Q

According to the World health Organization, __% of the lifetime UV radiation exposure occurs by 18 years of age.

A

dd

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11
Q

Where do you see an increase of UV radiation?

A
  1. closer to the equator
  2. higher altitude (1000ft up increases UV by 4%)
  3. 10am-2pm (60% of the UV falling on Earth)
  4. During summer and autumn
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12
Q

Peak solar ultraviolet radiation intensities are typically experienced in which season?

A

summer

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13
Q

What reduces the UV radiation?

A

greater the path traveled (increase air mass)
the lower the sun is from its zenith (increase Zenith angle)
Turbidity (attenuation by atmospheric aerosols)

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14
Q

Exposure to UV-B can be reduced by __% by wearing a hat with a brim.
Exposure to UV-B can be reduced by __% by wearing a hate with a brim with glasses with ordinary plastic lenses.

A

50, 95

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15
Q

Transitions Optical National Survey (2002)
__% respondents knew UV can cause skin cancer
__% respondents knew that UV can harm the eyes
__% of the respondents wear sunglasses

A

79, 6, 18

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16
Q

Crown glass covers ___nm and below.

A

340

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17
Q

CR-39 covers ___nm and below.

A

400

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18
Q

Polycarbonate covers ___nm and below.

A

420

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19
Q

Is there an affect on the amount of UV being transmitted going from Tint #1 to #2 to #3?

A

No affect

20
Q

Crizal Sun places an AR coating on the front or back side of the lens to eliminate glare and reflections?

A

back-side

21
Q

ANSI Z80.3 requirements for ________, ________, ________, and ________ properties.

A

flammability, cosmetic, refractive, transmittance

22
Q

What is Eye-Sun Protection Factor (E-SPF)?

A

helps consumers determine how much total UV radiation is entering the eye. (UV through the lens and UV reflected from the back surface of the lens into the eye)

23
Q

What degrees has the maximum reflection of UV radiation into the eye with Eye-Sun Protection Factor?

A

140-155

24
Q

To have an E-SPE of 50, about __% of the incident UV would be entering the eye.

A

2

25
Q

Crizal sunshield UV has an E-SPF of __.

A

50+

26
Q

the EPF rating is based on what 4 protection criteria?

A
  1. frame coverage
  2. ultra-violet (UV) protection
  3. blue light protection
  4. infrared protection
27
Q

Which protections carry more weight?

A

UV protection > blue light protection > infrared light protection

28
Q

T/F Cocoons OVERx are sunglasses that can be worn over prescription eyewear or contact lenses.

A

True

29
Q

According to ANSI, how much UV-A and UV-B UV-blocking contact lenses must minimally absorb?

A

70% UV-A

95% UV-B

30
Q

What are the two classes of UC blocking contact lenses, according to FDA and ANSI?

A

FDA Class 1 blocking (block 90% UVA, 95% UVB) - for high exposures
FDA Class 2 blocking (block 70% UVA, 95% UVB) - for general purposes

31
Q

Between which months have the high UV index in LA?

A

march to october

32
Q

T/F The amount of UV radiation absorbed by photochromic lenses is relative to their darkness?

A

False. it’s relative to the material of the lense

33
Q

T/F The higher the index, the less UV transmission.

A

True

34
Q

Does putting a coating on the lenses block some of the UV?

A

Yes. CR-39 with LIte-Guard UV coating can move the UV block from 370nm to 420nm

35
Q

T/F AR coating in the back can reduce visible glare but it reflects UV radiation off the back-side of the lens into the eyes.

A

True

36
Q

Which ANSI standard is street eyewear?

a. ANSI Z87.1
b. ANSI Z90.1
c. ANSI Z80.1

A

c. ANSI Z80.1

37
Q

Which is the ANSI standard for nonprescription sunglasses?

A

ANSI Z80.3

38
Q

What is the tolerance of nonprescription sunglasses?

A

Sphere: +0.12D to -0.25D sphere; Cylinder 0.12D
Prism: less than 1/4 prism diopter

39
Q

According to ANSI, UV-blocking contact lenses must absorb a minimum of __% of UV-A and __% of UV-B.

A

70, 95

40
Q

Percentage of UV being blocked or transmitted is a function of the lens ________.

A

thickness

41
Q

With peripheral light focusing (PLF), at what degree does the most UV-A + UV-B going into the eyes?

A

120

42
Q

T/F UV-blocking CL can block out most of the UV-B radiations whereas sunglasses, clear CL and none won’t have any effects.

A

True

43
Q

Is there a significant differences in UV transmission with worn and unworn contact lenses?

A

NO

44
Q

People who have worn UV-blocking contact lenses will have a macular pigment density levels greater or less?

A

Greater. This will lessen the chance of developing macular degeneration.

45
Q

What is the yellow lens cocoons OVERx?

A

it blocks the high energy blue and letting most of the visible spectrum in.

46
Q

According to the Global Solar UV Index, the higher the value, the _______ the potential for damage.

A

greater

47
Q

What is the UV index range according to the Global Solar UV Index?

A

0-11+

Vision Science 4 Dr. Drescher (2 decks)

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