ultraviolet radiation & the eye diana alrabe. sun safety protecting yourself from uv radiation

Ultraviolet Radiation & the eye

Diana Alrabe

SUN SAFETYSUN SAFETY

Protecting Yourself from UV Radiation

Ultraviolet Radiation - UV

What is Ultraviolet Radiation?


The sun is the energy source that sustains all life on earth.

Ultraviolet Radiation (UV) is simply one form of energy coming from the sun.

What is ultraviolet radiation?

Ultraviolet (UV) radiation is similar to visible light in all physical aspects, except that it does not enable us to see things. The light that enables us to see things is referred to as visible light and is composed of the colors we see in a rainbow. The ultraviolet region starts right after the violet end of the rainbow.

In scientific terms, UV radiation is electromagnetic radiation just like visible light, radar signals and radio broadcast signals. Electromagnetic radiation is transmitted in the form of waves. The waves can be described by their wavelength or frequency and their amplitude (the strength or intensity of the wave). Wavelength is the length of one complete wave cycle. For radiation in the UV region of the spectrum, wavelengths are measured in nanometers (nm), where 1 nm = one millionth of a millimeter.

Different wavelengths of electromagnetic radiation cause different types of effects on people. For example, gamma rays are used in cancer therapy to kill cancerous cells and infrared light can be used to keep you warm.

UV radiation has :

shorter wavelengths (higher frequencies) compared to visible light but have longer wavelengths (lower frequencies) compared to X-rays.

UV radiation is divided into three wavelength

What are some sources of ultraviolet radiation?

Sunlight is the greatest source of UV radiation. Man-made ultraviolet sources include several types of UV lamps, arc welding, and mercury vapour lamps.UV radiation is widely used in industrial processes and in medical and dental practices for a variety of purposes, such as killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy and suntanning. Different UV wavelengths and intensities are used for different purposes.

Some Devices Emitting UV Radiation

Bactericidal lampsBlack light lamps

Carbon, xenon and other arcs

Dental polymerizing equipment

Fluorescence equipmentHydrogen and deuterium

lamps

Metal halide lampsMercury lampsPlasma torches

Phototherapy lamps Printing ink polymerizing

equipmentWelding equipment

What are some health effects of exposure to UV radiation?

Some UV exposure is essential for good health. It stimulates vitamin D production in the body. In medical practice, UV lamps are used for treating psoriasis (a condition causing itchy, scaly red patches on the skin) and for treating jaundice in new born babies.

Excessive exposure can damage the skin and the eyes. The severity of the effect depends on the wavelength, intensity, and duration of exposure.

Effect on the eyes

The eyes are particularly sensitive to UV radiation. Even a short exposure of a few seconds can result in a painful, but temporary condition known as photokeratitis and conjunctivitis. Photokeratitis is a painful condition caused by the inflammation of the cornea of the eye. The eye waters and vision is blurred. Conjunctivitis is the inflammation of the conjunctiva (the membrane that covers the inside of the eyelids and the sclera, the white part of the eyeball);which becomes swollen and produces a watery discharge. It causes discomfort rather than pain and does not usually affect vision.

EYE EFFECT

Examples of eye disorders resulting from UV exposure include "flash burn", "ground-glass eye ball", "welder's flash" and "snow blindness" - depending on the source of the UV light causing the injury.

The symptoms are pain, discomfort similar to the feeling of sand in the eye and an aversion to bright light.The eyes are most sensitive to UV radiation from 210 nm to 320 nm (UV-C and UV-B).

Maximum absorption by the cornea occurs around 280 nm. Absorption of UV-A in the lens may be a factor in producing cataract (a clouding of the lens in the eye).


Sunlight contains 3 types of UV rays…


1.1. UVAUVA—causes skin aging & wrinkles. Used in tanning beds. Colors skin and gives false sense of protection from the sun. UVA rays pass effortlessly through the ozone layer.


2.2. UVBUVB—causes sunburns, cataracts, immune system damage, skin cancer. Melanoma may be associated with severe UVB sunburns occurring before the age of 20. Most UVB rays are absorbed by the ozone layer.


3.3. UVCUVC—these rays are the most dangerous. Fortunately, these rays are blocked by the ozone layer and don’t reach the earth.


Even on cloudy, cool, or overcast days, UV rays travel through the clouds and reflect off sand, water, snow, and even concrete.

Clouds and pollution don’t filter out UV rays, and can give a false sense of protection.

This “invisible sun” can cause unexpected sunburn and skin damage.


The sun’s light is strongest when it is highest in the sky (normally from 10 AM to 4 PM).

UV rays are strongest during the summer.

UV intensity is greater at high altitudes. Skiers need to take extra care.


The UV Index* predicts the next day’s UV levels on a 0-10+ scale.

*Developed by the National Weather Service and the EPA.

UV Index Number

Exposure Level

Minutes to Burn

0 to 2 Minimal 60

3 to 4 Low 45

5 to 6 Moderate 30

7 to 9 High 15

10+ Very high 10

Effects of UV Exposure

Sunburn


SunburnSunburn


Sunburn develops when the amount of Sunburn develops when the amount of UV exposure is greater than the UV exposure is greater than the protection your skin’s melanin can protection your skin’s melanin can provide.provide.

The lighter your skin, the less melanin it The lighter your skin, the less melanin it has to absorb UV and protect itself.has to absorb UV and protect itself.

All skin, no matter the color, thickens and All skin, no matter the color, thickens and hardens with continued sun exposure, hardens with continued sun exposure, resulting in wrinkles later in life.resulting in wrinkles later in life.


Eye Damage


Spending long hours in the sun with Spending long hours in the sun with no eye protection may increase your no eye protection may increase your chance of developing cataracts.chance of developing cataracts.

Even low amounts of sunlight can Even low amounts of sunlight can increase the risk of eye disorders.increase the risk of eye disorders.

UVB damage to the eyes is UVB damage to the eyes is cumulative, so it is never too late to cumulative, so it is never too late to start protecting your eyes.start protecting your eyes.


Skin Damage


There are about 1.3 million new There are about 1.3 million new cases of skin cancer in the U.S. cases of skin cancer in the U.S. each year, resulting in about 9,800 each year, resulting in about 9,800 deaths.deaths.

Melanoma is one type of skin Melanoma is one type of skin cancer. It is the most common cancer. It is the most common cancer among women between the cancer among women between the ages of 25 and 29.ages of 25 and 29.


Skin cancer is the most common of Skin cancer is the most common of cancers and is largely preventable.cancers and is largely preventable.

Increased outdoor leisure time, less Increased outdoor leisure time, less clothing worn outdoors, and clothing worn outdoors, and decreased ozone levels are partly to decreased ozone levels are partly to blame.blame.


““Sun damage” causes wrinkles, Sun damage” causes wrinkles, easy bruising, brown “liver” spots, easy bruising, brown “liver” spots, and potentially, skin cancer.and potentially, skin cancer.


Scientists believe sunburns can Scientists believe sunburns can alter the body’s immune system for alter the body’s immune system for up to 24 hours after exposure to the up to 24 hours after exposure to the sun.sun.

Repeated overexposure to UV Repeated overexposure to UV radiation can cause more damage to radiation can cause more damage to the body’s immune system, even in the body’s immune system, even in people with dark skin.people with dark skin.

Guidelines for Protection

Eye Protection


Sunglasses offer excellent Sunglasses offer excellent protection.protection.

Make sure the lenses are designed Make sure the lenses are designed to block out 95% of UV.to block out 95% of UV.

Polarizing lenses and mirror Polarizing lenses and mirror finishes reduce glare, but have little finishes reduce glare, but have little effect in blocking the absorption of effect in blocking the absorption of UV rays.UV rays.


Tanning Protection


Sunscreen doesn’t offer 100% Sunscreen doesn’t offer 100% protection.protection.

SPF 30+ sunscreen blocks 96% of SPF 30+ sunscreen blocks 96% of UV; SPF 15+ blocks out 93%.UV; SPF 15+ blocks out 93%.

In addition to sunscreen, wear a hat, In addition to sunscreen, wear a hat, sunglasses, more clothing, and seek sunglasses, more clothing, and seek shade.shade.


Using SPF 30+ instead of SPF 15+ Using SPF 30+ instead of SPF 15+ does not mean you can safely does not mean you can safely double your time in the sun.double your time in the sun.

Apply sunscreen 20 minutes before Apply sunscreen 20 minutes before going outside. Don’t rub it in—a going outside. Don’t rub it in—a light film should stay visible.light film should stay visible.


Protective Clothing


Appropriately designed clothing is Appropriately designed clothing is great for protecting you from the great for protecting you from the sun.sun.

Sun Safety

ultraviolet radiation & the eye diana alrabe. sun safety protecting yourself from uv radiation

Documents

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