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vision science 5 (Dr, Dre) > lect 1 UV radiation and non-rx sunglasses > Flashcards

lect 1 UV radiation and non-rx sunglasses Flashcards

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1
Q

(T or F) Polycarb lenses are required per California law for children under 18

A

False, they are not required by California state law

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2
Q

(T or F) Polycarb lenses are required per California law for police officers

A

False, however, the “standard of care” does require polycarb lenses for certain pt’s like those with dangerous occupations, amblyopes, and monoculars, etc

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3
Q

(T or F) According to ANSI, lenses for a myope must have a minimum thickness of 2mm

A

False, there is not a state or federal law regarding minimum thickness, but the lenses do have to pass a drop ball test.

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4
Q

Which of the following are in order from shorter wavelength to longer wavelength

A) IR-C, IR-B, IR-A, VISIBLE LIGHT, UV-A, UV-B, UV-C
B) IR-A, IR-B, IR-C, VISIBLE LIGHT, UV-C, UV-B, UV-A
C) UV-A, UV-B, UV-C, VISIBLE LIGHT, IR-C, IR-B, IR-A
D) UV-C, UV-B, UV-A, VISIBLE LIGHT, IR-A, IR-B, IR-C

A

D) UV-C, UV-B, UV-A, VISIBLE LIGHT, IR-A, IR-B, IR-C

UV-C=100-290NM
IR-C=3MICROMETERS-1MM

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5
Q

ultraviolet has a ______ effect, while infrared has a ______ effect

A) photochemical, thermal
B) thermal, photochemical

A

A) photochemical, thermal

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6
Q

Uv light would be more likely to cause _____, while infrared would likely cause _____. Both IR and UV can cause _____ and _____.

A) retinal lesions, corneal burns, cataracts and photokeratitis
B) photokeratitis, corneal burns, cataracts and retinal lesions
C) cataracts, glaucoma, retinal lesions and corneal burns
D) glaucoma, retinal lesions, cataracts, and corneal burns

A

B) photokeratitis, corneal burns, cataracts and retinal lesions

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7
Q

What is the reason why Pterygiums are found mostly on the nasal side?

A) because less light falls on the nasal conj and cornea
B) because of Steinberg’s principle
C) because of the peripheral light focusing principal
D) Pterygiums are usually only found on the temporal side

A

C) because of the peripheral light focusing principal….PLF says that oblique light is refracted from the periphery and concentrated on the nasal side and are implicated as factors for pterygiums and age-related cataracts.

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8
Q

intensity of light reaching the nasal limbus is _____ times higher than the intensity of the temporal incident light

A

20

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9
Q

Which of the following is not a major concern with regards to optical radiation since the ozone layer blocks most of this from entering our atmosphere

A) UV-A
B) UV-B
C) UV-C
D IR-A

A

C) UV-C

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10
Q

what can prevent damage from PLF (peripheral light focusing)?

A

wrap around sun glasses

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11
Q

Which two of these places would have the most UV?

A) top of a mountain
B) bottom of a valley (below sea level)
C) Mauna Loa, HI
D) Norfolk, VA

A

A) top of a mountain and C) Mauna Loa, HI (more UV=higher altitude and lower latitude)

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12
Q

Your pt comes in with an off-axis pterygium, which of the following is NOT advice you should give:

A) wear a hat with a brim
B) wear wrap around sun glasses
C) refer to ophthalmologist for removal before it enters patients visual axis
D) keep eyes moist

A

C) refer to ophthalmologist for removal before it enters patients visual axis. if it is not affecting vision, do not remove it. it will more than likely grow back anyway.

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13
Q

Studies show that corneal epithelium helps to block UV radiation. What case can you think of where a patient’s corneal epithelium is compromised and it would be important for you to educate that pt on UV exposure?

A

PRK/lasiks patients-cornea becomes de-epithealized. It takes a couple days for it to heal.

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14
Q

(T or F) The lens transmits more UV than the cornea

A

False, the cornea transmits light at the 300nm range and the lens doesn’t transmit light until 400nm (UV-A, B, and C are in the ranges 100nm to 400nm) therefore the cornea transmits more UV light than the lens)

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15
Q

(T or F) According to the World Health Organization, 80% of the lifetime UV radiation exposure occurs by 18 years of age

A

true, so educate parents on the importance of UV protection for their children

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16
Q

Every _____ feet increase in altitude is a ____% increase in UV

A) 400ft, 10%
B) 4000ft, 24%
C) 1000ft, 4%
D) 100ft, 6%

A

C) 1000ft, 4%

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17
Q

UV is the highest between:

A) 8am and 10am
B) 10am and 2 pm
C) 12pm and 4pm
D) 4pm and 6pm

A

B) 10am and 2 pm (also highest in the summer months)

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18
Q

which order is in highest to lowest UV exposure by season:

A) summer, autumn, spring, winter
B) summer, spring, autumn, winter
C) spring, autumn, summer, winter
D) winter, spring, summer, autumn

A

A) summer, autumn, spring, winter

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19
Q

Which is by far the largest reflector of UV:

A) asphalt
B) sand
C) snow
D) water

A

C) snow (important to educate your snowboarding/skiing pt’s on UV exposure from snow reflected light and higher UV levels at higher altitudes)

20
Q

Which one of the following does NOT reduce UV:

A) turbidity
B) increased air mass
C) increased zenith angle
D) decreased latitude

A

D) decreased latitude

21
Q

(Tor F) There is a clear association with UV-B exposure and cortical cataracts

A

true (from the chesapeake bay study)

22
Q

(T or F) there is no association between UV-A exposure and cortical or nuclear cataracts

A

true (from the chesapeake bay study)

23
Q

(T or F) there is no association between UV-B exposure and nuclear cataracts

A

true (from the chesapeake bay study)

24
Q

(T or F) UV-B exposure can be reduced by 50% by wearing a hat with a brim and reduced by 95% by wearing a hat with a brim and glasses with ordinary plastic lenses

A

true

25
Q

A grade 4 cortical cataract would show:

A) severe yellowing along with 20/100 vision or worse
B) bloodshot red, can no longer see white
C) all 4 quadrants of the lens contain spoke like features
D) on axis blocking no matter how many quadrants were affected

A

C) all 4 quadrants of the lens contain spoke like features

26
Q

What are 2 examples of photosensitizing medications

A

Accutane and tetracycline

27
Q

(T or F) children’s pupils are smaller, therefore they have less risk of UV exposure in their eyes

A

false, they are larger and are at higher risk for UV damage

28
Q

Which material transmits the most UV:

A) CR-39
B) hi-index plastic
C) polycarb
D) crown glass

A

D) crown glass

29
Q

(T or F) the amount of UV radiation absorbed by photochromatic lenses (like transitions) is not relative to how dark they get

A

true-it is the material of the lens that blocks UV, not the tint.

30
Q

(T or F) crown glass is not recommended as lenses for patient who work outdoors because crown glass allows UV light to pass thru

A

true

31
Q

Which lens is better at blocking UV

A) tint #3 (darkest)
B) tint #2 (medium)
C) tint #1 (lightest)
D) they are all the same in regards to how much UV they block or transmit

A

D) they are all the same in regards to how much UV they block or transmit (remember it is the lens material that determines UV protection)

32
Q

(T or F) The higher the index of refraction, the lower the UV transmission

A

true

33
Q

Ansi standards for street eyewear fall under _____, while ansi stds for safety glasses fall under _____

A) Z87.1, Z80.1
B) Z80.1, Z87.1
C) Z83.1, Z81.3
D) Z81.3, Z83.1

A

B) Z80.1, Z87.1

34
Q

Which 2 are true regarding Anzi Z80.3 std’s of non-RX sunglasses:

A) sphere: plano tolerance of +0.12 to -.025D, cyl: 0.12D
B) prism: less than ¼ prism
C) lenses are never tested at the geometric center by a lensometer
D) non-RX sunglasses do not have impact resistance standards

A

A) sphere: plano tolerance of +0.12 to -.025D, cyl: 0.12D

B) prism: less than ¼ prism

35
Q

E-SPF is….

A

irrandiance (no lens)/irradiance (lens)

36
Q

What is FUBI?

A

it is the eye protection factor based on 1) Frame coverage 2) UV protection 3) Blue light protection and 4) Infrared protection (The final EPF rating is a result of averaging the scores of these 4 factors known by the acronym FUBI) FUBI ranges from 70-100 and a mid to high 90’s rating is good.

37
Q

(T or F) thinner CL lenses do not block as much UV as thicker CL lenses of the same material

A

true

38
Q

Between FDA class 1 and class 2 CL’s, which are better at blocking UV?

A

FDA class 1

39
Q

Does the UV transmission in CL’s between unworn and worn differ?

A

no, not significantly

40
Q

In patients who wore UV-blocking CL’s, were the macular pigment density levels greater or less than pt’s who wore minimally UV-blocking CL’s? what could that mean?

A

Macular pigment density levels were significantly greater in eyes that wore UV-blocking. This suggests that UV-blocking CL’s are better at reducing risk of macular degeneration. A lower density of macular pigment would be bad.

41
Q

You notice a pair of sunglasses say UV400, what on earth could that mean? :)

A

They block wavelengths under 400, so basically they block UV-A and B and C (the cocoon’s are UV400)

42
Q

What is a cocoon?

A) an insect’s UV-protected house
B) a device to allow only the “good” UV rays into your RX specs
C) sunglasses you can put over your RX spectacles or CL’s
D) darkly tinted film that you can put on the back side of your RX specs

A

C) sunglasses you can put over your RX spectacles or CL’s

43
Q

UV-B is blocked by the cornea and UV-A is blocked by the lens up to ____nm

A

390nm

44
Q

(T or F) IOL’s (intraocular lenses) transmit about the same UV light as the natural lens

A

true

45
Q

According to the UV index scale, levels of 8 or higher require ______

A) no protection
B) protection
C) extra protection

A

C) extra protection

1,2=no protection
3-7=protection
8-11=extra protection

vision science 5 (Dr, Dre) (2 decks)

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