28 - 197 - PHOTOPROTECTION

Question 1

peak UV hours

Answer 1

10:00 AM to 2:00 PM

Question 2

wavelength of UVB

Answer 2

290 - 320 nm

Question 3

wavelength of UVA2

Answer 3

320 - 340 nm

Question 4

wavelength of UVA1

Answer 4

340 - 400 nm

Question 5

accounts for 5% to approximately 10% of the UV light that reaches the surface of the earth

Answer 5

UVB

Question 6

accounts for **95% of the UV that reaches the surface of the earth **because it can penetrate through clouds and glass windows, and is not obstructed by the ozone layer

Answer 6

UVA1

Question 7

this UV is present all the time, regardless of cloud cover or other obstruction

Answer 7

UVA1

Question 8

it is more likely to cause pigmentation than any other wavelength

Answer 8

UVA1

Question 9

it induces reactive oxygen species (ROS), which cause damage to blood vessels, collagen fibers, and elastic fibers located deep under the skin, and are involved in skin aging

Answer 9

UVA1

Question 10

An ideal photoprotection method

Answer 10

avoid sunlight

Question 11

UV decreases by _% as the latitude increases by _°

Answer 11

UV decreases by** 3%** as the latitude increases by 1°

ecause atmosphere becomes thinner as altitude increases, UV increases by 4% every 300 meters from the horizon.

Snow, sand, and metal can reflect up to 90% of UV.

UV is reduced by 50% to approximately 95% under the shade; hence, one should stay in the shade if possible

Question 12

formula for SPF

Answer 12

SPF is the ratio of the minimal erythema dose (MED) of a subject’s sunscreen-protected skin over the MED of the unprotected skin.

Current FDA guidelines specifically require that products be tested using a solar simulator with emission spectrum covering the wavelength range of 290 nm to 400 nm, and that the sunscreen product be applied at a concentration of 2 mg/cm2 .

Question 13

what is the concentration of sunscreen specified for SPF testing

Answer 13

**2 mg/cm2 **- equivalent of 1 oz (30 mL) of sunscreen to cover the entire body surface

Question 14

SPF15 blocks how many percent of UVB

Answer 14

93.3%

Question 15

SPF30 blocks how many percent of UVB

Answer 15

96.7%

Question 16

SPF is accepted as the worldwide standard for the assessment of protection against the erythemogenic effects of what UV rays?

Answer 16

UVB and UVA2

Question 17

what method is used to evaluate protection against UVA?

Answer 17

persistent pigment darkening (PPD) method

Question 18

UVA protection factor formula

Answer 18

In the PPD method, the dose of UVA required to induce PPD observed 2 to 24 hours after exposure of s**unscreen-protected skin is compared to that of sunscreen-unprotected skin; **the ratio is then expressed as the UVA protection factor

Question 19

The European Union requires UVA protection factor to be at least ____ of the labeled SPF, with the PPD method as the assessment of the UVA protection.

Answer 19

one-third

Question 20

To label a sunscreen product as “broad spectrum,” it should have a critical wavelength of at least ____ nm.

Answer 20

370 nm

Question 20

wavelength at which the area-under-the-absorbance-curve represents 90% of the total area-under-the-curve in the UV region

Answer 20

critical wavelength

Question 21

the nomenclature used in the FDA Sunscreen Monograph

Answer 21

United States Adopted Name (USAN)

Question 22

2 catrgories of UV filters

Answer 22

1. Organic (chemical) Filters
2. Inorganic (physical) Filters

Question 23

The most widely used UVB filter worldwide

Answer 23

octinoxate (ethylhexyl methoxycinnamate)

Question 24

the most widely used **UVA** filter

Answer 24

**oxybenzone** (benzophenone-3)

Question 25

Question 26

Weak UVB absorbers; good substantivity—used in **water-resistant sunscreens and hair-care products**

Answer 26

Trolamine salicylate

Question 27

Water soluble; e**nhances sun protection factor** of the final product

Answer 27

Ensulizole

Question 28

Most commonly used UVA filter

Answer 28

Oxybenzone

Question 29

most common cause of photoallergic contact dermatitis to UV filters

Answer 29

Oxybenzone

Question 30

Photounstable; enhances the photodegradation of octinoxate

Answer 30

Avobenzone

Question 31

what are examples of inorganic filters?

Answer 31

1. Titanium dioxide 2. Zinc oxide

Question 32

has lower refractive index compared to microfine titanium dioxide and thus appears **less white**

Answer 32

**micronized zinc oxide**

Question 33

When the size of inorganic filter is larger than ____ nm, they can protect skin from all the wavelengths of UV

Answer 33

200 nm

Question 34

Give one advantage of inorganic filters

Answer 34

Inorganic filters are not allergenic and do not react with skin, and are thus recommended for children and adults with allergies. ## Footnote However, inorganic filters are not preferred and are restricted in use because they leave a white coating behind. If applied too often, they may be comedogenic.

Question 35

Give examples of UV filters that are unstable and degrades during UV exposure

Answer 35

* **avobenzone** (butyl methoxydibenzoylmethane; Parsol 1789) *** padimate O **(ethylhexyl dimethyl PABA) * **octinoxate** (ethylhexyl methoxycinnamate) ## Footnote It is possible to incorporate other agents to increase the photostability of the final product (Fig. 197-3). Most of these agents are photostable UV filters (eg, octocrylene, salicylates, oxybenzone) that absorb photons to minimize the effect on the photounstable UV filter; they also serve as receptor molecules for energy transfer from excited state photounstable filter, hence minimizing the photodegradation of the latter

Question 36

most common causes of UV filter photoallergy

Answer 36

**Octocrylene**, **oxybenzone** (benzophenonone-3), and **avobenzone** (butyl methoxydibenzoylmethane) ## Footnote No photoallergy has been reported with inorganic UV filters (titanium dioxide and zinc oxide).

Question 37

what will you advice regarding the use of sunscreens in children younger than age 6 months

Answer 37

For this group of patients, it is prudent to use other means of photoprotection, such as clothing

Question 38

what is the sunscreen option for children less than 2 years old

Answer 38

Children younger than 2 years old should use **inorganic** sunscreen rather than organic sunscreen.

Question 39

The peak action spectrum for previtamin D synthesis

Answer 39

300 ± 5 nm

Question 40

MED and frequency of sun exposure sufficient for humans to produce the daily needed Vitamin D

Answer 40

The amount of UVB required to produce daily needed vitamin D in humans is not so much; **exposure of 0.33 or 0.5 MED 2 or 3 times a week** to arms, hands, and face is sufficient. ## Footnote In other words, a person with skin type II who lives in Boston needs only 5 minutes at noon in July. According to another study, arms and legs can create 3000 IU by being exposed to 0.5 MED of UVB. Therefore, **lightskinned** people can produce sufficient vitamin D by staying under midday sunlight for **5 to approximately 30 minutes, twice a week.**

Question 41

For those individuals who are concerned or are at risk for vitamin D insufficiency, a balanced diet and a daily ____ IU vitamin D 3 supplement, along with __ g of calcium, is recommended

Answer 41

** 600 IU **vitamin D3 supplement, along with **1 g **of calcium

Question 42

Active Ingredients for Oral Photoprotection

Answer 42

Question 43

examples of flavonoids

Answer 43

■ Catechins ■ Isoflavones (genistein, silymarin) ■ Proanthocyanidins

Question 44

examples of Nonflavonoids

Answer 44

■ Phenolic acid (benzoic, gallic, and cinnamic [caffeic, ferulic, and p-coumaric] acids) ■ Resveratrol

Question 45

this flavonoid is mainly present in tea leaves

Answer 45

Catechins

Question 46

The major active component of silymarin

Answer 46

**silibinin**, which has been shown to protect against photocarcinogenesis in animals

Question 47

this is a group of substances widely present in **grape seeds**

Answer 47

Proanthocyanidins

Question 48

This nonflavonoid appear mostly in **red wine and tea**

Answer 48

Phenoic Acid

Question 49

stilbene found in grapes, red wine, and nuts, is also a potential polyphenolic antioxidant

Answer 49

Resveratrol

Question 50

examples of nonpolyphenolic phytochemicals

Answer 50

carotenoids and caffeine

Question 51

the in-vitro measurement used in many countries to quantify the ability of fabrics to protect against UV

Answer 51

UV protection factor (UPF)

Question 52

What UPF is classified as having "good protection"?

Answer 52

UPF**15** to UPF**24**

Question 52

What UPF is classified as having **"very good protection"**?

Answer 52

UPF**25** to UPF**39**

Question 52

best UV absorber garment

Answer 52

Polyester fibers

Question 52

poorest UV absorber garment

Answer 52

cotton and rayon

Question 52

What UPF is classified as having **"excellent protection"**?

Answer 52

UPF40 to UPF50+

Question 53

**Laundering** garments made from** cotton or rayon** _ _ _ _ _ the UPF because of shrinkage, causing a decrease in the porosity of the fabrics

Answer 53

increases

Question 54

Wetness _ _ _ _ _ the UV protection of a light-colored (especially white) garment

Answer 54

decreases ## Footnote This is because the protective effect of white cotton fabric is mainly from light-scattering at the fiber–air interface: when wet, the fabric no longer scatters light and the garment becomes more transparent to both UV and visible light In contrast, dark-colored garments absorb light and thus do not become see-through or provide less UV protection when wet.

Question 55

what UV ray is absorbed by the cornea?

Answer 55

UVB ## Footnote Mainly UVB is absorbed by the cornea to damage it; in addition, UVA, the longer UV wavelengths, damages the lens and further provokes cataracts.

Question 56

what UV ray damages the lens?

Answer 56

UVA ## Footnote Mainly UVB is absorbed by the cornea to damage it; in addition, UVA, the longer UV wavelengths, damages the lens and further provokes cataracts.

Question 57

What rays impair the retina?

Answer 57

Visible and infrared rays

Question 58

to protect the retina, what color of sunglasses should be worn?

Answer 58

Consequently to protect the retina, **yellow-colored or red-colored sunglasses,** which can block blue or purple light, are preferred.

Question 59

time of maximum UV exposure to the eye

Answer 59

8:00 and 10:00 AM and 2:00 and 4:00 PM, when solar radiation is parallel to the eye

Question 60

The amount of visible light transmitted through the lens

Answer 60

luminous transmittance ## Footnote a lens with 20% luminous transmittance would allow 20% of the visible light to pass through

Question 61

The standard requires that the UVB transmittance be __% of the luminous transmittance

Answer 61

5% ## Footnote Lenses are grouped into 5 categories (0 to 4), ranging from fashion sunglasses (lens category 0) to specialpurpose sunglasses for very high sun-glare reduction (lens category 4); category 4 lenses are not to be worn during driving. Category 0 lenses are allowed to have luminous transmission of 80% to 100%, whereas category 4 transmission is limited to 3% to 8%.

Question 62

The standard also mandates that the minimum vertical diameter for adult sunglasses is ___ mm, and for children, ___ mm.

Answer 62

adult - 28 mm children - 24 mm

Question 63

Dietary supplementation with at least ____IU/day of vitamin D 3 (cholecalciferol) is thus recommended for all patients with photosensitive disorders who avoid sun and use sunscreens

Answer 63

at least **400 IU/day** of vitamin D 3

Question 64

Question 65

provided safe and effective photoprotection through eumelanin synthesis in patients with erythropoietic protoporphyria

Answer 65

**Afamelanotide (analog of human α-melanocyte–stimulating hormone)**