Spectacle Transmission

Question 1

1-4
A-D
to denote color density
as number ascends…_

Answer 1

transmission reduces

Question 2

high plus or minus lenses have different transmission throughout lens; darker where _

Answer 2

thicker

Question 3

visible spectrum:

Answer 3

380-760 nm

Question 4

much UV and IR light doesn’t reach retina; it’s absorbed by:

Answer 4

cornea, aqueous humor, lens, vitreous humor

Question 5

less than 400 nm is considered:

what end is most harmful:

Answer 5

UV radiation

shorter wavelengths

Question 6

ocular damage caused by UV:

Answer 6

high burst

Question 7

a single dose of high level UV radiation

Answer 7

Welders burn

Question 8

excessive exposure to UV causes:

Answer 8

photokeratitis (snow blindness)

Question 9

it takes _ hrs after a burn to feel pain

-heals in _ hrs

Answer 9

6

6 to 24

Question 10

long term low dose UV results in:

Answer 10

cataracts

Question 11

_ are at risk for retinal problems due to UV

Answer 11

aphakic (macular degeneration)

Question 12

IOLs are _

Answer 12

UV absorbing

Question 13

best method to reduce UV related eye disease is:

Answer 13

sunglasses early in life

Question 14

only lens materially that inherently does not come with UV filter?
can do what?

Answer 14

CR-39

UV dye

Question 15

good quality polarizing lenses filter _

Answer 15

UV radiation

Question 16

Do photochromic lenses protect against UV light?

Answer 16

yes - in their darkened state

Question 17

glare control lenses block _

Answer 17

short blue wavelengths

Question 18

_ measure UV absorption

Answer 18

photometers

Question 19

How to test if lens absorbs UV?

Answer 19

place test lens over an unedged plastic photochromic lens and expose to sunlight - if photochromic darkens, test lens does not absorb it all

Question 20

frame selection for UV:
_ lens area
fits _
_ style

Answer 20

large
close to face
wrap

Question 21

when UV radiation combines with blue light and IR, causes lens opacification called:

Answer 21

glass blower’s cataracts

Question 22

sources of IR radiation:

Answer 22

molten substance (glass, metal)
arc lamps
IR lamps

Question 23

lenses that block IR

Answer 23

NoIO

IREX

Question 24

transmission for sunglasses is:

Answer 24

15-30%

Question 25

sunglasses that transmit less than 15% may present problems because of _

Answer 25

reflected glare from back surface (back surface AR fixes this)

Question 26

according to ANSI standards, sunglasses used for driving should not be darker than:

Answer 26

8%

Question 27

special purpose 3% transmission may be used for:

Answer 27

rock climbing, beach, skiing

Question 28

single exposure to ordinary bright light for 2-3 hours caused dark adaptation to start _ minutes later caused normal night vision to be delayed by _

Answer 28

10 | several hours

Question 29

dark adaptation loss can be prevented with sunglasses that have transmission between:

Answer 29

10-15%

Question 30

``` normal 20/20 through glass windshield: _ through 82% transmission pink lenses: _ green tinted windshield: _ together: _ ```

Answer 30

20/32 20/40 20/46 20/60

Question 31

Does a light tint reduce glare at night? Use what?

Answer 31

no (they do reduce internal reflections) | AR - increase transmission, increase contrast sensitivity

Question 32

crown glass and plastic transmit _%

Answer 32

92

Question 33

pink lens benefit?

Answer 33

transmit light uniformly (no color distortion) | reduces glare because it reduces internal reflections

Question 34

yellow are advocated for _ driving because they enhance contrast

Answer 34

fog/haze, night driving

Question 35

most common color used in germany, higher absorption in shorter wavelengths like with yellow lenses

Answer 35

brown

Question 36

lens color that has a transmission curve close to color sensitivity of human eye, good UV and IR too

Answer 36

green

Question 37

green is a very _ tint

Answer 37

comfortable

Question 38

most popular color for sun protection

Answer 38

gray

Question 39

gray offers _ transmission

Answer 39

uniform

Question 40

best lens color for color vision deficient patients

Answer 40

gray

Question 41

4 categories for sunglasses

Answer 41

1. cosmetic 2. general purpose 3. very dark 4. strongly colored (selective filtration)

Question 42

color deficient individuals cannot discriminate red and green traffic signals through _ lens color

Answer 42

brown

Question 43

tinting plastic lenses: longer dip = _ _ color

Answer 43

darker | uniform

Question 44

lenses are darker in the upper portion of lens

Answer 44

gradient tinting

Question 45

_ does not tint at all, all tint is absorbed by scratch coating

Answer 45

polycarb

Question 46

advantage of color coating lenses:

Answer 46

uniform density regardless of thickness

Question 47

color coating lenses results in smoothness of its _

Answer 47

transmission curve

Question 48

Do internally tinted or color coating lenses allow more transmission?

Answer 48

color coating

Question 49

sunglass wearers can experience reflections on back surface from behind during the day, what would fix this?

Answer 49

back surface AR

Question 50

reflections on front surface from behind is noticeable at night from _, results in _

Answer 50

bright light source from behind, ghost images

Question 51

adjustments that can alleviate ghost images: (2)

Answer 51

pantoscopic faceform (neither eliminate)

Question 52

regardless of source, _ reduce ALL reflections

Answer 52

AR coatings

Question 53

mirrors are applied just like _

Answer 53

AR coatings

Question 54

mirror coatings _ transmission due to high amount of reflections, what %

Answer 54

reduce (by 15%)

Question 55

mirrors can be used in conjunction with _ to provide extra protection from intense sunlight

Answer 55

tints

Question 56

4 types of mirror lenses:

Answer 56

1. full mirrors 2. gradient mirrors 3. double mirrors 4. flash coatings (just a hint)