Sun protection for your eyes

• Introduction to eye protection
• What eye diseases are associated with exposure to sunlight?
• Environmental factors and UV exposure
• How do you protect your eyes from UV radiation?

Introduction to eye protection

Eyes are sensitive instruments which can easily become injured or diseased from exposure to sunlight, because of the ultraviolet (UV) rays of the sun. Ultraviolet rays are high energy,and are invisible to the human eye because they are outside the spectrum of colours that a human eye can see.

The eye, by its design, naturally provides some protection against UV rays. For example, eyelids will partially close to cover the eye in a squint when exposed to strong light. However, the eye’s natural protection is only partial, and any exposure to sunlight creates a risk of developing eye diseases and disorders. The extent of the risk varies depending on both the quality (e.g. the angle of the sun’s rays) and quantity (i.e. length of exposure) of sunlight, and the protective measures taken by an individual to reduce eye exposure to UV rays while in sunlight.

What eye diseases are associated with exposure to sunlight?

Exposure to sunlight can cause damage to the eyes in both the short and long term. In the short term, exposure to sunlight can result in:

• Mild irritation: May cause symptoms such as excessive blinking, swelling or difficulty seeing in strong sunlight.
• Photo keratoconjunctivitis: Photo keratoconjunctivitis is a condition similar to snow blindness or welder’s flash burn. It occurs when the sensitive, skin-like tissues of the eyeball become sunburnt. Individuals suffering from the condition are likely to experience severe pain, and possibly temporary blindness, for 12 days. The condition is temporary and will resolve naturally.

In the long term, exposure to sunlight is associated with a range of eye diseases, including:

• Eye cancer (also known as squamous cell carcinoma of the eye): A rare condition characterised by the growth of cancerous cells on the surface of the eye. The World Health Organisation (WHO) estimates that 50–70% of eye cancers around the world are caused by sun exposure. The risk of developing eye cancer increases with lifetime exposure to sunlight. The incidence is highest in countries closest to the equator.
• Cortical and posterior subcapsular cataract: Cataracts are characterised by the increasing opaqueness of the lens of the eye. It can lead to impaired eye sight and, in severe cases, to blindness. The WHO estimate 5% of cortical cataract disease is caused by sun exposure. In Australia, the Australian Cancer Council estimates that up to 10% of all cataracts are associated with excessive sun exposure. A study of a United States population found that individuals who had high levels of sun exposure were about 1.5 times more likely to develop cortical or posterior subcapsular cataracts than those who had low sun exposure, while those with moderate sun exposure were about 1.2 times more likely to develop each of these types of cataracts.
• Pterygium: Pterygium is characterised by a fleshy growth on the eye’s surface. The WHO estimates that 4070% of the global burden from this disease is attributable to sun exposure. A study conducted in Victoria reported that 43.6% of pterygium cases were attributable to sun exposure.
• Age related macular degeneration: Based on laboratory studies showing that UV rays cause retinal damage in rats, scientists believe that exposure to UV rays contributes to the degeneration of eyesight which occurs naturally with ageing.

Environmental factors and UV exposure

The level of UV radiation varies due to a range of environmental factors,including:

• Time of day: UV radiation levels are highest when the sun is higher in the sky (in the middle of the day, between 10am and 2pm).
• Geographic location: UV radiation levels increase with increasing proximity to the equator, and increasing altitude.
• Cloud cover: UV radiation levels are higher when there is no cloud cover, although UV radiation from the sun is present even on cloudy days.
• Features of the surrounding landscape: As UV radiation from the sun is reflected more or less effectively by some surfaces than others, exposure to UV radiation is also influenced by features of the surrounding landscape. Snow is a particularly reflective surface, and as much as 80% of UV radiation will be reflected back (compared to about 10% for water and grass). Dry beach sand reflects about 15% of UV radiation, while the foam in sea water reflects 25% of UV radiation.
• Ozone protection: A layer of ozone forms a protective layer around the earth and blocks much of the suns harmful rays, including much UV radiation. Ozone levels vary between places and times of the day.

How do you protect your eyes from UV radiation?

Protecting the eyes from UV radiation from the sun is the only way to reduce the risk of eye damage. Staying out of the sun at all times is impossible, so it is important that you know how to protect your eyes when they are exposed to sunlight, and about the times at which the sun’s rays are most dangerous.

Steps for protecting against exposure to UV radiation from the sun include:

Wear sunglasses when exposed to sunlight

Every time an individual goes out in sunlight, they should wear sunglasses that meet the Australian standards. Sunglasses provide a barrier between UV radiation and the eyes,thus preventing the harmful effects of UV radiation. The Australian Cancer Council recommends that individuals wear sunglasses with wrap-around (i.e. side) protection complying with Australian Standard AS/ANZ 1067:2003 (these standards outline how manufacturers should make sunglasses and which materials they should use). Sunglasses which meet the Australian Standard will be labelled with AS/ANZ 1607:2003 and a category number. In addition, the lenses of the sunglasses should offer a high level of UV protection, and be labelled UV400, or EPF9 or 10.

Wear a broad-brimmed hat when exposed to sunlight

A hat with a broad brim offers better protection than a cap, as it also blocks sunlight from the side and back. Such a hat can effectively block about 40% of UV rays from reaching the eye. It not only protects the eyes from exposure to sunlight, but also the ear, neck and face. Exposure at these sites can increase the risk of cancer.

Avoid exposure to sunlight as much as possible, particularly in the middle of the day

Levels of UV radiation in sunlight are highest in the middle of the day (10am to 2pm), and thus exposure to sunlight is most dangerous at this time. Limit your exposure to sunlight at this time by staying indoors, wearing protective clothing or using shaded areas.

Sit or walk in the shade

The shade provided by trees and canopies does not offer full protection against UV radiation, but staying out of full sunlight does offer considerable protection against UV rays. Seek shady areas when outside, particularly when outside for extended periods or in the middle of the day.

Avoid indoor sun tanning lamps

Indoor tanning lamps emit UV radiation and can cause damage to the eyes and skin. Avoid indoor tanning if you wish to protect your eyes from their damaging effects.

It is also important to realise that children’s eyes are susceptible to damage from UV exposure (even though this damage may not produce symptoms until they reach adulthood). In order to protect children’s eyes, parents and guardians should provide children with appropriate protective eyewear and a broad-brimmed hat, and limit their exposure to sunlight, particularly in the middle of the day.

References

1. Cancer Council Australia, Eye Research Australia. Eye protection from ultraviolet radiation [online]. 30 August 2006 [cited 17 February 2009]. Available from: [URL link] 
2. Optometrists Association Australia. Ultraviolet and the eye [online]. 2009 [cited 17 February 2009]. Available from: [URL Link] 
3. Vecchio P, Hietanen M, Stuck BE, et al [eds]. Protecting workers from ultraviolet radiation. Oberschleiheim, Germany: International Commission on Non-Ionizing Radiation Protection; 2007. Available from: [URL link]
4. Repacholi M. Global solar UV index [online]. World Health Organisation. August 2002 [cited 17 February 2009]. Available from: [URL link]
5. World Health Organisation. Global disease burden from solar ultraviolet radiation [online]. July 2006 [cited 17 February 2009]. Available from: [URL link]
6. Newton R, Ferlay J, Reeves G, et al. Effect of ambient solar ultraviolet radiation on the incidence of squamous-cell carcinoma of the eye. Lancet. 1996; 347(9013): 1450-1.
7. Collman GW, Shore DL, Shy CM, et al. Sunlight and other risk factors for cataract: an epidemiological study. Am J Public Health. 1988; 78(11): 1459-62.
8. National Eye Institute. Facts about the cornea and corneal disease [online]. US National Institutes of Health. December 2008 [cited 17 February 2009]. Available from: [URL link]