Lec.1 Ultraviolet Radiation & Nonprescription

Question 1

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.

Answer 1

40, 32, 28

Question 2

Electromagnetic spectrum for ultraviolet is _____nm.

Answer 2

100-400

Question 3

Electromagnetic spectrum for visible spectrum is _____nm.

Answer 3

400-700

Question 4

Electromagnetic spectrum for infrared spectrum is ____.

Answer 4

760nm-1mm

Question 5

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

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

Answer 5

1. c
2. b
3. a

Question 6

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

Answer 6

nasal corneal limbus, lens cortex

Question 7

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

Answer 7

True

Question 8

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

Answer 8

20

Question 9

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

Answer 9

120

Question 10

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

Answer 10

dd

Question 11

Where do you see an increase of UV radiation?

Answer 11

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

Question 12

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

Answer 12

summer

Question 13

What reduces the UV radiation?

Answer 13

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

Question 14

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.

Answer 14

50, 95

Question 15

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

Answer 15

79, 6, 18

Question 16

Crown glass covers ___nm and below.

Answer 16

340

Question 17

CR-39 covers ___nm and below.

Answer 17

400

Question 18

Polycarbonate covers ___nm and below.

Answer 18

420

Question 19

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

Answer 19

No affect

Question 20

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

Answer 20

back-side

Question 21

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

Answer 21

flammability, cosmetic, refractive, transmittance

Question 22

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

Answer 22

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)

Question 23

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

Answer 23

140-155

Question 24

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

Answer 24

2

Question 25

Crizal sunshield UV has an E-SPF of __.

Answer 25

50+

Question 26

the EPF rating is based on what 4 protection criteria?

Answer 26

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

Question 27

Which protections carry more weight?

Answer 27

UV protection > blue light protection > infrared light protection

Question 28

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

Answer 28

True

Question 29

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

Answer 29

70% UV-A | 95% UV-B

Question 30

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

Answer 30

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

Question 31

Between which months have the high UV index in LA?

Answer 31

march to october

Question 32

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

Answer 32

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

Question 33

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

Answer 33

True

Question 34

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

Answer 34

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

Question 35

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.

Answer 35

True

Question 36

Which ANSI standard is street eyewear? a. ANSI Z87.1 b. ANSI Z90.1 c. ANSI Z80.1

Answer 36

c. ANSI Z80.1

Question 37

Which is the ANSI standard for nonprescription sunglasses?

Answer 37

ANSI Z80.3

Question 38

What is the tolerance of nonprescription sunglasses?

Answer 38

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

Question 39

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

Answer 39

70, 95

Question 40

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

Answer 40

thickness

Question 41

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

Answer 41

120

Question 42

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.

Answer 42

True

Question 43

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

Answer 43

NO

Question 44

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

Answer 44

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

Question 45

What is the yellow lens cocoons OVERx?

Answer 45

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

Question 46

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

Answer 46

greater

Question 47

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

Answer 47

0-11+