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7 Facts You Need to Know About Sunscreen

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woman wearing flower and sunglasses holding sunscreen with a sun drawn on her back

Did you know skin if your largest organ? That is why everyone should wear sunscreen everyday. Wearing sunscreen prevents skin aging, pigmentation, and most importantly, skin cancer. If your face or eyes are sensitive, mineral sunscreen is a better choice. Here are some commonly asked questions about sunscreen, and why it is so important.

1. Why do I need to use sunscreen?

The sun radiates harmful UV rays. There are three types of UV rays; UVA, UVB, UVC.

  • The UVA rays (remember: A for aging) is 95% of the UV radiation that reaches the earth’s surface. Consistent exposure to UVA rays damages the collagen proteins and cells in deep layers of your skin. This can lead to pigmentation (tanning) and wrinkles. 
  • The UVB rays (remember: B for burning) affect the top layer of your skin and cause sunburns – the red, itchy, peeling skin you may experience after spending a whole day in the sun.  
  • While both UVA and UVB can cause early aging and skin cancer, the UVC rays do not reach the earth’s surface since the atmosphere absorbs them. You don’t have to worry about these!

Broad Spectrum sunscreen blocks out both UVA and UVB rays. It helps reduce the risk of skin cancer and prevents the skin from aging and pigmentation, decreasing wrinkling and discoloration. 

Why you need sunscreen. Which UV rays reach up to what layers of skin. UV penetration into the layers of the skin.
Figure shows how different UV rays reach different layers of your skin.

2. Who should use sunscreen?

  • Everyone! Men, women, and children should all use sunscreen, regardless of how easily they tan.
  • Especially, if you are exposed to the sun, indoors or outdoors, or even stepping out or driving on cloudy and overcast days, you should be using sunscreen.  

3. How much UV rays can pass through windows?

  • If you work by a window, you should be aware that the rays from the sun can also penetrate windows.
  • Although UVB rays are mostly blocked by glass, more than 50% of UVA rays can still pass through the glass, reaching your skin and thus causing aging and wrinkles. 

4. What UV rays are present during cloudy days?

  • Just because there isn’t any visible sunlight on a cloudy, overcast, or rainy day, doesn’t mean that there are no UV rays present.
  • Clouds might reduce the amount of rays that reach the earth, but UVA and UVB rays can still penetrate through the clouds and rain.  

5. What sunscreen should I use?

  • A sunscreen with a broad spectrum SPF of 30 or higher is the bare minimum. However, you should also consider the type of active ingredients utilized in the sunscreen.
  • The two types of sunscreen are mineral and chemical sunscreens. You should select the one that best suits your preferences.
    1. Mineral sunscreen contains ingredients such as zinc oxide and titanium dioxide, which block and scatter rays before they can penetrate the skin.
    2. Chemical sunscreen contains ingredients such as oxybenzone and octisalate, which reflect the UV rays before they can damage the skin. 
  • Both types have been proven to be safe and effective. However, because mineral sunscreens use naturally-occurring minerals to do their job, they’re less likely to cause skin irritation. If you are going to be swimming in the ocean, mineral sunscreen is also safe for coral reefs.

6. When should I use sunscreen, and how do I apply it?

  • Sunscreen isn’t just for days at the beach and the pool. Sunscreen should be applied everyday, 15 minutes before sun exposure, and reapplied every two hours that you are under the direct sun.
  • If you are sitting near windows, sunscreen should also be worn indoors. Even when the forecast is cloudy, sunscreen should also be applied before going outside.. 

7. How does the sun affect my eyes?

Sunscreen should be applied to every part of the body that will be exposed to the sun, including the ears, neck, and especially the skin around the eyes such as eyelids

People often forget to apply sunscreen around the eyes. The eyelids are less than 0.2 mm thick, making them one of the thinnest layers on the body. Because they’re so delicate, they are one of the first places to show signs of aging. While the eyelids make up only 1% of the body’s surface area, eyelid cancer accounts for 5 to 10% of all skin cancers, making your eyelids especially important to protect. 

If you have particularly sensitive eyes, mineral sunscreen formulas are a great alternative to chemical ones. 
Protecting your eyes from the sun is one of the top priorities for everyone. Sunscreen and UV-protective sunglasses are a must! 

If you would like to further consult, our experienced eye doctors here at Advanced Eye Physician would be happy to help evaluate your eyes and maintain the health that your eyes deserve! 

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Written by Nancy Tsai, MD

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