Ultraviolet Light Examples and Protecting Your Vision - List of Things That Reflect or Emit UV

Latest update: April 11, 2023. Page URL indicates original publication date; meanwhile, times change and the updates continue.

Another Summer Approaches...

The Sun in Ultraviolet Light

It is fairly common knowledge ultraviolet light destroys vision and causes blindness over time. The effects of ultraviolet light are cumulative. How well you protect your eyes when younger will directly affect your vision as you become older. All information on this page has been derived from federal websites, studies, research, archives, etc.

Sources That Emit Ultraviolet Light Rays - Never Look Directly at Them

• Some halogen, fluorescent, and incandescent lights (found everywhere). Yep, not a good idea to stare directly at any light bulb for long periods of time.
• Mercury vapor lighting (often used in stadiums and school gyms)
• Specifically designed UV lights found at many nightclubs
• Tanning booths 
• Some types of lasers
• Sun

Sources That Reflect Ultraviolet Light Rays

• Pavement
• Cement, e.g., sidewalks
• Water
• Snow
• Grass
• Sand
• Moon (Earth's atmosphere filters out most of it)
• Pretty much anything white in sunlight
• Aluminum and aluminum-based coatings

From an astronomical point of view, NASA has an interesting page about ultraviolet light at Tour of the Electromagnetic Spectrum - Ultraviolet Waves.

Environmental Factors Affecting Ultraviolet Exposure

This federal website explains these factors best: FDA direct sub-page. Detailed information for:

• Geography
• Altitude
• Time of year
• Time of day
• Weather conditions

The relevant segment is located a little over halfway down their page. Most of it is pretty obvious, though clouds and shade do not protect one as much as people think. UV rays are usually most intense from 10:00 am to 4:00 pm.

The Obvious as to Contacts, Prescription Glasses, Sunglasses and UV Exposure

As everyone who needs their vision corrected knows, we are always offered a UV light protection coating for our lenses when buying glasses; I always agree to it. Folks who wear contacts are given the same option; the contacts are made of a material that absorbs the ultraviolet light part of the spectrum; however, it should be remembered that the contact does not cover the entire eye.

Wearing sunglasses without UV protection is worse than wearing no glasses at all and can even be dangerous; the eyes can be fooled into dilating, causing maximum and damaging exposure to ultraviolet radiation. Here is an eye-opening (so to speak) article by NASA: Ultraviolet-Blocking Lenses Protect, Enhance Vision. The NASA article is a little off-topic, but the message is clear; do spend whatever time, money, and effort necessary to be sure the sunglasses you buy actually do their job. The wrong sunglasses could ultimately subtract years of vision from your life; or at minimum, cause severe problems such as macular degeneration and cataracts. One really does not want to experience retina injections and/or cataract surgery in their later years.

Ultraviolet Light Phobia

Almost last, but not least. One should not decide to be phobic concerning UV rays. The body needs ultraviolet light to manufacture the vitamin D3 necessary in order to stay healthy.

In-Depth, Scientific Research and Studies of Environmental Ultraviolet (UV) Reflectance

For the science and tech oriented, there is the lengthy article: Ultraviolet Radiation Albedo and Reflectance. If so inclined, be prepared to set aside an hour or two.

[An Update]

As a result of the COVID-19 pandemic, consumers are buying and using unregulated UVC light devices for disinfection purposes. The FDA is now warning that these unregulated UVC devices can cause eye damage and skin burns. If you are considering buying such a device, here is a cautionary article from CNET: UVC wands kill viruses. They're also a 'major safety issue,' experts warn.

[An Update]

As recently as two days ago, there are research reports definitively stating that ultraviolet LED lights kill the COVID-19 virus. These lights are only to be used where they are not visible, e.g. inside ventilation systems, etc. This research has not been reported in mainstream media; my guess is that it was generally decided it would cause a repeat of August or worse.

[An Update]

Other than the usual advisory concerning summer, not much new to report.

[An Update]

Here is a ncbi/nlm/nih.gov page that explains exactly what is happening with UV light, your eyes, your glasses and UV/blue filters: Spectral Evaluation of Eyeglass Blocking Efficiency of Ultraviolet/High-energy Visible Blue Light for Ocular Protection. Here is an excerpt: ...ultraviolet radiation ranging from 100 to 400 nm is harmful to the retina, whereas the visible spectrum of light from 400 to 700 nm is relatively safe. ... The earth's atmosphere absorbs almost all of ultraviolet C (100 to 280 nm) and most of ultraviolet B (280 to 315 nm) light. Ultraviolet A (315 to 400 nm), visible light (380 to 760 nm), and infrared (>760 nm) are able to reach the earth's surface. ...<end excerpt>

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