197: Photoprotection Flashcards
1
Q
What are the different types of UV radiation and their characteristics?
A
UVB: 290 nm - 320 nm, accounts for 5% - 10% of UV light, high energy, induces erythema.
UVA2: 320 nm - 340 nm, longer wavelength, less energy than UVB.
UVA1: 340 nm - 400 nm, low energy, penetrates clouds and glass, induces ROS, may cause pigmentation, present all the time.
2
Q
What factors influence UV radiation exposure?
A
UV radiation is strongest between 10:00 AM and 2:00 PM.
UV decreases by 3% for every degree of latitude increase.
UV increases by 4% for every 300 meters of altitude.
Snow, sand, and metal can reflect up to 90% of UV.
UV is reduced by 50% to approximately 95% under shade.
3
Q
What is the significance of SPF in sunscreen?
A
SPF (Sun Protection Factor) is the ratio of the minimal erythema dose (MED) of sunscreen-protected skin to that of unprotected skin.
SPF15 blocks 93.3% of UVB, while SPF30 blocks 96.7%.
The actual in-use SPF is often lower than the labeled SPF due to insufficient application (typically 0.5 to 0.8 mg/cm² used instead of the recommended 2 mg/cm²).
4
Q
How does the ozone layer affect UV radiation exposure?
A
The ozone (O3) layer absorbs all UVC, most UVB, and barely any UVA.
When the sun is highest, UV penetration is shorter, leading to more UV reaching the earth’s surface.
5
Q
What are the historical developments in sunscreen ingredients?
A
PABA (para-aminobenzoic acid) was the first UVB filter.
Benzophenone was the first UVA filter.
6
Q
What is the effective SPF when applying SPF30 sunscreen at 0.5 mg/cm²?
A
The effective SPF would be significantly lower, approximately SPF3, when applied at 0.5 mg/cm² instead of the recommended 2 mg/cm².
7
Q
How does altitude affect UV exposure?
A
UV exposure increases by 4% for every 300 meters of altitude above the horizon.
8
Q
How much UVB does SPF15 sunscreen block, and how much is absorbed into the skin?
A
SPF15 blocks 93.3% of UVB, and 6.7% is absorbed into the skin.
9
Q
How much UVB does SPF30 sunscreen block, and how much is absorbed into the skin?
A
SPF30 blocks 96.7% of UVB, and 3.3% is absorbed into the skin.
10
Q
How does the cumulative UV damage compare between SPF15 and SPF30?
A
The added protection from SPF30 halves the cumulative UV damage compared to SPF15, even though both prevent sunburn.
11
Q
How does SPF15 sunscreen affect the amount of radiation required to cause erythema?
A
The amount of radiation required to cause erythema increases by 15 times after the use of SPF15 sunscreen.
12
Q
What MED would a 30-minute exposure with SPF15 sunscreen result in?
A
A 30-minute exposure with SPF15 sunscreen would result in only 20% of an MED.
13
Q
How does SPF15 compare to SPF30 in blocking UVB?
A
SPF15 blocks 93.3% of UVB, while SPF30 blocks 96.7% of UVB.
14
Q
What is the effective SPF if SPF30 is applied unevenly?
A
The effective SPF would be approximately SPF3 if only half the recommended amount is applied.
15
Q
How does chronic exposure to SPF15 compare to SPF30?
A
With chronic exposure, SPF30 provides significantly better protection, halving the cumulative UV damage compared to SPF15.
16
Q
How much UVB is absorbed into the skin when using SPF15 sunscreen?
A
6.7% of UVB is absorbed into the skin when using SPF15 sunscreen.
17
Q
How much UVB is absorbed into the skin when using SPF30 sunscreen?
A
3.3% of UVB is absorbed into the skin when using SPF30 sunscreen.
18
Q
What is the purpose of the PPD in sunscreen products?
A
PPD (Persistent Pigment Darkening) measures the dose of UVA required to induce a reaction on sunscreen-protected skin compared to unprotected skin, expressed as the UVA protection factor.
19
Q
What is the critical wavelength in sunscreen testing?
A
The critical wavelength is the wavelength at which the area under the absorbance curve represents 90% of the total area under the curve in the UV region. It is important for labeling a sunscreen as ‘broad spectrum’ and indicates effective UVA protection.
20
Q
What are the two categories of UV filters used in sunscreens?
A
UV filters are divided into two categories: organic filters (which include UVB and UVA filters) and inorganic filters (such as titanium dioxide and zinc oxide).
21
Q
What are the characteristics of inorganic filters in sunscreens?
A
Inorganic filters like titanium dioxide and zinc oxide are photostable, do not react with organic filters, are not allergenic, and can protect against all wavelengths of UV when larger than 200 nm. They may also be comedogenic if applied too often.
22
Q
What is the significance of photostability in UV filters?
A
Photostability is crucial as it determines how well a UV filter maintains its effectiveness during UV exposure. Photostable agents can absorb photons and minimize the degradation of photounstable filters, enhancing the overall efficacy of the sunscreen.
23
Q
What are the most common causes of UV filter photoallergy?
A
The most common causes of UV filter photoallergy are octocrylene, oxybenzone (benzophenone-3), and avobenzone (butyl methoxydibenzoylmethane).
24
Q
What is the critical wavelength requirement for a sunscreen to be labeled as ‘broad spectrum’ in the United States?
A
The critical wavelength must be at least 370 nm for a sunscreen to be labeled as ‘broad spectrum’ in the United States.
25
How can the stability of avobenzone-based sunscreen be improved?
Photostable UV filters like octocrylene, salicylates, or oxybenzone can be incorporated to absorb photons and minimize the photodegradation of avobenzone.
26
What is a potential drawback of octinoxate in sunscreen?
Octinoxate is photounstable and degrades during UV exposure, reducing its effectiveness.
27
What additional statement might be included on a sunscreen labeled as 'broad spectrum' with SPF15?
The label might include the statement: 'If used as directed with other sun protection measures, decreases the risk of skin cancer and early skin aging caused by the sun.'
28
What are the potential health concerns associated with titanium dioxide in sunscreen?
Titanium dioxide may have negative health effects if absorbed into the skin, although studies have shown it does not penetrate beyond the stratum corneum.
29
What combinations are not allowed by FDA guidelines for avobenzone?
The FDA does not allow avobenzone to be combined with PABA, padimate O, or inorganic filters like titanium dioxide and zinc oxide.
30
How does the size of micronized titanium dioxide affect its photoprotection?
Micronized titanium dioxide (10-100 nm) scatters less visible light, does not leave a white coating, but its ability to block UV radiation decreases.
31
What is a common concern associated with oxybenzone in sunscreen?
Oxybenzone is a common cause of photoallergy among UV filters.
32
What role do salicylates play in sunscreen formulations?
Salicylates are photostable UV filters that absorb photons to minimize the photodegradation of photounstable UV filters.
33
Can a sunscreen with a critical wavelength of 360 nm be labeled as 'broad spectrum'?
No, the sunscreen cannot be labeled as 'broad spectrum' because the critical wavelength must be at least 370 nm.
34
What benefit does octocrylene provide in sunscreen?
Octocrylene is a photostable UV filter that helps stabilize photounstable filters like avobenzone.
35
What is the consequence of uneven application of SPF30 sunscreen?
Uneven application results in an uneven distribution of UV filters, reducing the sunscreen's effectiveness.
36
How often should SPF30 sunscreen be reapplied according to FDA guidelines?
Sunscreen should be reapplied every 2 hours according to FDA guidelines.
37
What does the UVA protection factor (PPD) indicate in sunscreen products?
The UVA protection factor (PPD) indicates the dose of UVA radiation required to induce a reaction on sunscreen-protected skin compared to unprotected skin, expressed as a ratio.
38
What criteria must a sunscreen meet to be labeled as 'broad spectrum' in the United States?
To be labeled as 'broad spectrum', a sunscreen must have a critical wavelength of at least 370 nm, ensuring it provides protection against both UVA and UVB radiation.
39
How does the critical wavelength relate to the effectiveness of a sunscreen?
The critical wavelength is the point at which 90% of the total area under the absorbance curve in the UV region is represented, indicating the sunscreen's ability to protect against UVA radiation effectively.
40
What are the two main categories of UV filters used in sunscreens?
The two main categories of UV filters are organic filters (which include UVB and UVA filters) and inorganic filters. Organic filters are often referred to as chemical filters, while inorganic filters are known as physical filters.
41
What are the characteristics of inorganic UV filters like titanium dioxide and zinc oxide?
Inorganic filters such as titanium dioxide and zinc oxide are photostable, do not react with organic filters, are not allergenic, and can protect against all wavelengths of UV radiation when their size is larger than 200 nm.
42
What is the role of avobenzone in sunscreens, and what is its limitation?
Avobenzone is an excellent UVA filter but is photounstable, meaning it degrades during UV exposure, which limits its effectiveness unless stabilized with other agents.
43
Why is it important to reapply sunscreen every 2 hours?
Sunscreen should be reapplied every 2 hours because it can be removed by rubbing, water, or sweat exposure, and to ensure consistent protection against UV radiation.
44
What are the most common causes of UV filter photoallergy?
The most common causes of UV filter photoallergy are octocrylene, oxybenzone, and avobenzone, which can trigger allergic reactions in some individuals.
45
What is the FDA's recommendation regarding the use of avobenzone in combination with other filters?
The FDA guidelines do not allow avobenzone to be combined with PABA, padimate O, or inorganic filters like titanium dioxide and zinc oxide due to potential interactions that may affect efficacy.
46
How does the size of inorganic filters affect their protective capabilities?
When the size of inorganic filters is larger than 200 nm, they can protect the skin from all wavelengths of UV radiation, as well as reflect and scatter visible and infrared rays.
47
What is the recommended type of sunscreen for children younger than 2 years old?
Children younger than 2 years old should use inorganic sunscreen rather than organic sunscreen.
48
What is the prevalence of photoallergy to UV filters?
The prevalence of photoallergy to UV filters is very low, much less than 1%.
49
What are the three sources of vitamin D?
1. Exposure to the UVB spectrum of sunlight converts 7-dehydrocholesterol in the skin to previtamin D by photoisomerization.
2. Previtamin D converts to vitamin D by heat isomerization.
3. Subsequently, vitamin D is hydroxylated in the liver and kidneys to its active form.
50
What is the effect of sunscreens on vitamin D levels?
Normal usage of sunscreens does not generally result in vitamin D insufficiency. This is primarily due to the inadequate application of sunscreen.
51
What is recommended for individuals at risk for vitamin D insufficiency?
For individuals concerned or at risk for vitamin D insufficiency, a balanced diet and a daily 600 IU vitamin D3 supplement, along with 1 g of calcium, is recommended.
52
What is the role of tocopherol (Vitamin E) in skin protection?
Tocopherol (Vitamin E) plays a role in protection from oxidative damage by eliminating reactive oxygen species (ROS). It is oxidized to tocoferoxyl radical by ROS and can be regenerated by vitamin C.
53
What type of sunscreen should be used for children under 2 years old?
Inorganic sunscreen should be used for children under 2 years old because it is less likely to cause allergic reactions and does not penetrate beyond the stratum corneum of the skin.
54
What recommendations would you provide to a patient concerned about vitamin D deficiency due to rigorous photoprotection?
Recommend a balanced diet, a daily supplement of 600 IU vitamin D3, and 1 g of calcium. This is especially important for elderly individuals, dark-skinned individuals with modest sun exposure, and those practicing rigorous photoprotection.
55
What does the evidence suggest about the safety of nanoparticulate inorganic sunscreen ingredients during pregnancy?
Studies regarding the safety of nanoparticulate inorganic ingredients during pregnancy are not available, but these ingredients do not penetrate beyond the stratum corneum of the skin.
56
Why does continuous sunlight exposure not lead to vitamin D intoxication?
Continuous sunlight exposure does not lead to vitamin D intoxication because previtamin D3 and vitamin D3 are photodegraded when constantly exposed to sunlight.
57
What systemic absorption concerns exist for benzophenone-3?
Up to 2% of an applied dose of benzophenone-3 and its metabolites can be excreted in the urine, indicating systemic absorption.
58
What is the recommended type of sunscreen for children younger than 2 years old and why?
Children younger than 2 years old should use inorganic sunscreen rather than organic sunscreen due to concerns about percutaneous absorption.
59
What precautions should be taken regarding sunscreen use in pregnant women?
During pregnancy, sunscreen is recommended to prevent skin damage from UV radiation, such as pigmentary disorders. Sunscreen has been proven safe by toxicology tests, but studies on the safety of nanoparticulate inorganic ingredients during pregnancy are not available.
60
What is the significance of vitamin D synthesis in relation to UV exposure?
Vitamin D synthesis requires exposure to the UVB spectrum of sunlight, which converts 7-dehydrocholesterol in the skin to previtamin D.
61
What is the significance of vitamin D synthesis in relation to UV exposure?
Vitamin D synthesis requires exposure to the UVB spectrum of sunlight, which converts 7-dehydrocholesterol in the skin to previtamin D. Continuous exposure to sunlight does not produce vitamin D proportionally due to photodegradation of previtamin D and vitamin D3.
62
How does the use of sunscreen affect vitamin D levels in individuals?
Normal usage of sunscreens does not generally result in vitamin D insufficiency. This is primarily due to the inadequate application of sunscreen, rather than the sunscreen itself blocking vitamin D synthesis.
63
What dietary sources can significantly contribute to vitamin D levels?
Dietary sources that can significantly contribute to vitamin D levels include oily saltwater fish (like herring, salmon, and sardines), cod liver oil, and egg yolk.
64
What is the relationship between systemic absorption of organic UV filters and their metabolites?
Systemic absorption of organic UV filters has been reported, with up to 2% of an applied dose of benzophenone-3 and its metabolites being excreted in the urine.
65
What is the risk associated with using sunscreens containing nanostructured titanium dioxide or zinc oxide?
The risk for humans from using sunscreens that contain nanostructured titanium dioxide or zinc oxide is considered negligible, as studies show they do not penetrate beyond the stratum corneum of the skin.
66
What is the effect of SPF16 broad-spectrum sunscreen on nonmelanoma skin cancer incidence?
SPF16 broad-spectrum sunscreen has been shown to decrease the incidence of squamous cell carcinoma and basal cell carcinoma by 38% and 25%, respectively.
67
What is the recommended vitamin D intake for individuals at risk of vitamin D insufficiency?
For individuals concerned about vitamin D insufficiency, a balanced diet and a daily 600 IU vitamin D3 supplement, along with 1 g of calcium, is recommended.
68
What role does tocopherol (vitamin E) play in skin protection?
Tocopherol (vitamin E) plays a role in protection from oxidative damage by eliminating reactive oxygen species (ROS). It can be regenerated by vitamin C, glutathione, and coenzyme Q10.
69
What is the role of nicotinamide in skin protection against UV radiation?
Nicotinamide prevents adenosine triphosphate depletion induced by UV radiation, boosting cellular energy and enhancing DNA repair. It is safe and effective in reducing the rates of new nonmelanoma skin cancers and actinic keratoses in high-risk patients.
70
How do polyphenols contribute to skin protection from UV-induced damage?
Polyphenols, found in fruits, vegetables, coffee, tea, red wine, nuts, cereal, and chocolate, exhibit intrinsic antioxidant activity. They act as hydrogen or electron donors to free radicals, helping to protect against cutaneous inflammation, oxidative stress, UV-induced DNA damage, and carcinogenesis.
71
What are the benefits of carotenoids in photoprotection?
Carotenoids, including beta-carotene, lycopene, and astaxanthin, are effective antioxidants for photoprotection. They help prevent erythema formation from UV radiation and reduce UV-induced skin damage.
72
What is the significance of the Ultraviolet Protection Factor (UPF) in clothing?
The Ultraviolet Protection Factor (UPF) measures the ability of fabrics to protect against UV radiation. It quantifies how much UV radiation can penetrate through clothing, with higher UPF values indicating better protection. UPF is a better reflection of UVB than UVA protection.
73
What factors affect the UV protectiveness of garments?
Several factors affect the UV protectiveness of garments: 1. Fabric Type: Polyester fibers are the best UV absorbers, while cotton and rayon are the poorest. 2. Laundering: Laundering garments made from cotton or rayon increases UPF due to shrinkage, decreasing fabric porosity. 3. Wetness: Wetness decreases the UV protection of light-colored garments, as wet fabric becomes more transparent to UV and visible light.
74
How does wetness affect the UV protection of a white cotton shirt?
Wetness decreases the UV protection of a white cotton shirt because the fabric becomes more transparent to UV and visible light when wet.
75
How does polyester compare to cotton or rayon in UV protection?
Polyester fibers are the best UV absorbers, while cotton and rayon are the poorest.
76
What role does nicotinamide play in protecting against UV-induced skin damage?
Nicotinamide prevents adenosine triphosphate depletion induced by UV radiation, boosting cellular energy and enhancing DNA repair. It is safe and effective in reducing the rates of new nonmelanoma skin cancers and actinic keratoses in high-risk patients.
77
How do polyphenols contribute to skin protection against UV radiation?
Polyphenols, found in fruits, vegetables, coffee, tea, red wine, nuts, cereal, and chocolate, exhibit intrinsic antioxidant activity that helps protect against cutaneous inflammation, oxidative stress, UV-induced DNA damage, and carcinogenesis in vivo.
78
What are the benefits of carotenoids in photoprotection?
Carotenoids, including beta-carotene, lycopene, and astaxanthin, are effective antioxidants that help prevent erythema formation resulting from UV radiation and provide photoprotective activity against UVA.
79
What is the significance of the Ultraviolet Protection Factor (UPF) in clothing?
The Ultraviolet Protection Factor (UPF) quantifies the ability of fabrics to protect against UV radiation, with higher UPF values indicating better protection. UPF is a better reflection of UVB than UVA protection.
80
What factors affect the UV protectiveness of garments?
Factors affecting UV protectiveness include: 1. Fabric type: Polyester fibers are the best UV absorbers, while cotton and rayon are the poorest. 2. Laundering: Increases UPF due to shrinkage, decreasing fabric porosity. 3. Wetness: Reduces UV protection of light-colored garments as wet fabric becomes more transparent to UV and visible light.
81
How does the consumption of green tea polyphenols affect UV-induced skin reactions?
Consuming green tea polyphenols has been shown to decrease UV-induced erythema in women, indicating a protective effect against skin damage from UV radiation.
82
What is the photoprotective effect of resveratrol?
Resveratrol, found in grapes, red wine, and nuts, is a polyphenolic antioxidant that suppresses UV-induced malignant tumor progression in mice, highlighting its potential in skin protection.
83
What are the recommended classifications of garment UV protection in the United States?
In the United States, garments are classified as having: - Good protection: UPF15 to UPF24 - Very good protection: UPF25 to UPF39 - Excellent protection: UPF40 to UPF50+.
84
What is the role of flavonoids in UV protection?
Flavonoids, such as catechins and isoflavones, provide photoprotective effects by preventing UV-induced skin damage and inflammation, with specific compounds like genistein exerting protective effects in animal models.
85
How does the presence of a wide-brimmed hat contribute to UV protection?
A wide-brimmed hat is recommended as it can protect wider areas of the body, including the forehead, eyes, and nose, which are often exposed to UV radiation.
86
What is the effect of dark-colored garments on UV protection?
Dark-colored garments absorb light and do not become see-through or provide less UV protection when wet.
87
How does glass filter UV radiation?
UVB is effectively filtered by glass, and many types of glass also provide good UVA2 and UVA1 protection (up to 380 nm).
88
What are the potential eye damages caused by UV radiation?
UV radiation can damage the cornea, conjunctiva, lens, and retina, leading to conditions such as photokeratitis, cataracts, and macular degeneration.
89
What is luminous transmittance in sunglasses?
Luminous transmittance is the amount of visible light transmitted through the lens; for example, a lens with 20% luminous transmittance allows 20% of visible light to pass through.
90
What are the categories of sunglasses according to the 2003 Australian Standard?
The categories are: | Category | Description | Luminous Transmission | |----------|-------------|---------------------| | 0 | Fashion sunglasses | 80-100% | | 1 | - | - | | 2 | - | - | | 3 | - | - | | 4 | Special purpose sunglasses for very high sun glare reduction | 3-8% |
91
What is the recommended vitamin D supplementation for photosensitive skin disease patients?
Dietary supplementation with at least 400 IU/day of vitamin D3 (cholecalciferol) is recommended for patients with photosensitive disorders who avoid sun exposure and use sunscreens.
92
What is the maximum allowed UVB transmittance for sunglasses with a luminous transmittance of 20%?
The maximum allowed UVB transmittance is 1% (5% of the luminous transmittance of 20%).
93
What dietary supplementation is recommended for individuals with photosensitive skin who avoid sun exposure?
Dietary supplementation with at least 400 IU/day of vitamin D3 (cholecalciferol) is recommended for individuals with photosensitive skin who avoid sun exposure and use sunscreens.
94
What risk does using dark lenses without UV protection pose?
Dark lenses without UV protection may induce greater UV exposure due to pupil dilation, increasing the risk of UV damage.
95
When is the maximum UV exposure to the eyes?
The maximum UV exposure to the eyes occurs between 8:00 AM and 10:00 AM and 2:00 PM and 4:00 PM, when solar radiation is parallel to the eyes.
96
What is the effect of dark-colored garments on UV protection when wet?
Dark-colored garments absorb light and do not become see-through or provide less UV protection when wet.
97
How does optical whitening affect UV radiation transmission through fabric?
Optical whitening agents absorb UV radiation at 360 nm and convert it to a visible light wavelength of 430 nm, thereby decreasing UV transmission through the fabric.
98
What is the significance of UVB filtering by glass?
UVB is effectively filtered by glass, which helps protect against UV damage to the skin and eyes.
99
What type of glass is used in car windshields and its UV transmission characteristics?
Car windshields are made of laminated glass, which allows less than 1% of UV (300 nm to 380 nm) to pass through, providing good UV protection.
100
What is the recommended lens color for sunglasses to protect the retina?
Yellow-colored or red-colored sunglasses are preferred as they can block blue or purple light, protecting the retina.
101
What are the categories of sunglasses according to the 2003 Australian Standard?
The categories include: | Category | Description | Luminous Transmission | |----------|-------------|---------------------| | 0 | Fashion sunglasses | 80-100% | | 1 | - | - | | 2 | - | - | | 3 | - | - | | 4 | Special purpose sunglasses for very high sun glare reduction | 3-8% |
102
What is the maximum UVB transmittance allowed according to the Australian Standard?
The standard requires that the UVB transmittance be 5% of the luminous transmittance; for example, if the luminous transmittance is 20%, the allowed UVB transmittance is 1%.
103
What is the recommended vitamin D supplementation for patients with photosensitive disorders?
Dietary supplementation with at least 400 IU/day of vitamin D3 (cholecalciferol) is recommended for patients with photosensitive disorders who avoid sun exposure and use sunscreens.
104
What is the relationship between sun avoidance and vitamin D levels?
25-hydroxyvitamin D levels were found to be significantly lower among sun avoiders and daily sunscreen users compared to individuals who did not avoid the sun.
105
What is the clinical significance of UVA exposure in relation to cataracts?
UVA, the longer UV wavelengths, damages the lens and further provokes cataracts, highlighting the importance of UV protection for eye health.
106
How does the shape of sunglasses lenses affect UV protection?
The shape of the lenses should block light entering from the side to ensure good UV protection, as side light can contribute to UV exposure.
107
What is the difference between the Australian and U.S. sunglass standards?
The Australian Standard differs from the U.S. standard in the maximum amount of UVB transmission allowed and the definition of UVA, with compliance being voluntary in the U.S.
108
What are the potential chronic effects of UV exposure on the eyes?
Chronic UV exposure can lead to conditions such as cataracts, pterygium, and macular degeneration, emphasizing the need for protective measures.
109
What is the role of nonlaminated glass in buildings and cars regarding UV transmission?
Side and rear windows are usually made from nonlaminated glass that allows a higher level of UVA transmission, which can increase UV exposure indoors and in vehicles.
110
What is photokeratitis and its primary cause?
Photokeratitis is an acute UV damage condition primarily caused by UVB exposure, leading to inflammation of the cornea.
111
What is the importance of UV protection in sunglasses during outdoor activities?
Sunglasses are crucial during outdoor activities to protect against UV radiation, especially during peak sunlight hours when UV exposure is highest.
112
What is the significance of the minimum vertical diameter requirement for sunglasses?
The minimum vertical diameter requirement for adult sunglasses is 28 mm and for children is 24 mm, ensuring adequate coverage and protection from UV rays.
113
How does pupil dilation affect UV exposure with darker sunglasses?
Lenses with darker colors may induce greater exposure to UV due to pupil dilation, unless the lenses offer good UV protection.
114
What are the clinical implications of using sunscreen for individuals with lupus erythematosus?
Individuals with lupus erythematosus should use sunscreen to prevent exacerbation of photosensitivity, as they are at higher risk for UV-induced skin reactions.
115
What is the recommended action for individuals with photosensitivity regarding sun exposure?
Individuals with photosensitivity should avoid sun exposure and use sunscreens to protect their skin from adverse reactions to UV light.
116
What is the effect of visible light on solar retinitis?
Solar retinitis is caused by visible light, indicating that UV protection alone may not be sufficient for complete eye safety.
117
What is the role of sunglasses in preventing chronic eye conditions?
Sunglasses help prevent chronic eye conditions such as cataracts and macular degeneration by blocking harmful UV radiation.
118
What is the significance of UVA and UVB protection in sunglasses?
UVA and UVB protection in sunglasses is essential to prevent both immediate and long-term eye damage, including acute and chronic conditions.
119
What are the implications of using optical whitening agents in fabrics?
Optical whitening agents can decrease UV transmission through fabric, providing an additional layer of protection against UV exposure.
120
What is the relationship between UV exposure and the development of cataracts?
Long-term UV exposure, particularly UVA, is associated with the development of cataracts, highlighting the need for protective measures.
121
What is the relationship between UV exposure and the development of cataracts?
Long-term UV exposure, particularly UVA, is associated with the development of cataracts, highlighting the need for protective eyewear.
122
What are the recommendations for lens categories in sunglasses for different uses?
Sunglasses should be categorized based on their intended use, with specific recommendations for normal use, high exposure, and special purposes to ensure adequate UV protection.
123
What is the importance of compliance with sunglass standards?
Compliance with sunglass standards is important to ensure that consumers receive adequate UV protection, although it is voluntary in some regions.
124
What is the effect of infrared rays on the retina?
Infrared rays can impair the retina, emphasizing the need for sunglasses that provide comprehensive UV and infrared protection.
125
What is the clinical significance of vitamin D3 supplementation for photosensitive individuals?
Vitamin D3 supplementation is clinically significant for photosensitive individuals to maintain adequate vitamin D levels while avoiding sun exposure.
126
What is the primary goal for patients with xeroderma pigmentosum regarding UV radiation exposure?
The primary goal is to lessen the amount of UV radiation reaching the skin and eyes.
127
What type of clothing is recommended for individuals with xeroderma pigmentosum?
Special UV-blocking clothing treated with UV absorbers and blockers is recommended.
128
How often should sunscreen be reapplied during the day for effective protection?
Sunscreen should be reapplied every 2 to 3 hours during the day.
129
What is the effect of blue light on patients with erythropoietic protoporphyria?
Blue light activates accumulated phototoxic protoporphyrin, leading to severe neuropathic pain, swelling, and redness.
130
What is afamelanotide and its role in treating erythropoietic protoporphyria?
Afamelanotide is an analog of human α-melanocyte-stimulating hormone that provides safe and effective photoprotection through eumelanin synthesis in patients with erythropoietic protoporphyria.
131
What is the recommended daily intake of vitamin D3 for patients with photosensitive disorders?
Dietary supplementation with at least 300 IU/day of vitamin D3 (cholecalciferol) is recommended for patients with photosensitive disorders who avoid sun and use sunscreens.
132
What is the peak action spectrum for previtamin D synthesis?
The peak action spectrum for previtamin D synthesis is 300 ± 5 nm.
133
What is the most common cause of photoallergy among UV filters?
Oxybenzone is the most common cause of photoallergy among UV filters.
134
What is the significance of using broad-spectrum sunscreens with a sun protection factor (SPF) of 50 or greater?
Broad-spectrum sunscreens with SPF 50 or greater provide significant protection against both UVA and UVB radiation, reducing the risk of skin damage.
135
What is the relationship between UV exposure and exacerbation of cutaneous lupus erythematosus?
Although UV-induced skin lesions in patients with cutaneous lupus erythematosus can develop several weeks after UV exposure, the relationship between sun exposure and exacerbation of the condition does not seem obvious to the patient.
136
What measures should a patient with cutaneous lupus erythematosus take to minimize UV radiation exposure?
The patient should wear special UV-blocking clothing treated with UV absorbers and blockers, large-brimmed sun hats with UV-blocking material, and UVA- and UVB-blocking sunglasses. They should also use a highly effective sunscreen daily and reapply it every 2-3 hours.
137
What treatment has shown effective photoprotection for patients with erythropoietic protoporphyria?
Afamelanotide, an analog of human α-melanocyte-stimulating hormone, has provided safe and effective photoprotection through eumelanin synthesis in patients with erythropoietic protoporphyria.
138
What is the recommended type of sunglasses for individuals with photosensitivity?
Individuals with photosensitivity should wear UVA-blocking and UVB-blocking sunglasses that provide full eye coverage.
139
What are the main categories of UV filters listed in the U.S. FDA Sunscreen Monograph?
The main categories of UV filters are:
1. **Organic Filters**
- UVB Filters
- UVA Filters
2. **Inorganic Filters**
- Titanium dioxide
- Zinc oxide
140
What is the function of Octocrylene as a UV filter?
**Octocrylene** is a photostable UV filter that enhances the photostability of other filters, making it effective in sunscreen formulations.
141
Which UV filter is most commonly used for UVA protection and is also a common cause of phototoxic reactions?
**Oxybenzone** (Benzophenone-3) is the most commonly used UVA filter and is known to be the most common cause of phototoxic allergic contact dermatitis to UV filters.
142
What is the significance of using Zinc oxide in sunscreens?
**Zinc oxide** is used in sunscreens for its photostability and ability to enhance the photostability of the final product. It provides better UVA protection compared to micronized titanium dioxide and is commonly coated to maintain effectiveness as a sunscreen.
143
What are the absorption ranges for the UVB filter Octinoxate?
**Octinoxate** (Ethylhexyl methoxycinnamate) has an absorption range of **311 nm**, making it one of the most widely used UVB filters in sunscreen products.
144
What are the primary functions of organic UV filters in sunscreens?
Organic UV filters primarily absorb UV radiation and convert it into heat, which is then released from the skin. They are often more photostable and can provide a broader spectrum of UV protection.
145
How does the absorption range of Octinoxate compare to that of Oxybenzone in terms of UV protection?
Octinoxate has an absorption range of 311 nm, primarily providing UVB protection, while Oxybenzone absorbs UV radiation at 288 nm and 325 nm, offering both UVA and UVB protection.
146
What is the significance of the photostability of sunscreen ingredients?
Photostability is crucial for sunscreen ingredients as it determines how well they maintain their effectiveness when exposed to sunlight.
147
What are the potential side effects associated with the use of Oxybenzone in sunscreens?
Oxybenzone is associated with potential side effects such as phototoxic reactions and allergic contact dermatitis in some individuals.
148
How do the properties of Zinc Oxide enhance its effectiveness as a sunscreen ingredient?
Zinc Oxide is effective as a sunscreen ingredient due to its ability to provide broad-spectrum protection against both UVA and UVB rays.
149
What role does Octocrylene play in sunscreen formulations?
Octocrylene serves as a UV filter that absorbs UVB radiation and enhances the photostability of other sunscreen ingredients.
150
What are the differences in the absorption ranges of PABA derivatives compared to Cinnamate derivatives in sunscreens?
PABA derivatives primarily absorb UVB radiation with absorption peaks around 283 nm and 311 nm, while Cinnamate derivatives have absorption ranges around 311 nm and 289 nm.
151
What is the importance of using a combination of different UV filters in sunscreen formulations?
Using a combination of different UV filters in sunscreen formulations is important to achieve broad-spectrum protection against both UVA and UVB rays.
152
How does the use of inorganic filters like Titanium Dioxide and Zinc Oxide differ in terms of skin sensitivity and effectiveness?
Inorganic filters like Titanium Dioxide and Zinc Oxide are less likely to cause skin sensitivity and irritation compared to many organic filters.
153
What are the implications of using water-resistant sunscreen ingredients like Homosalate and Trolamine Salicylate?
Water-resistant sunscreen ingredients are designed to maintain their effectiveness during water exposure, making them ideal for swimming or sweating.
