In anticipation of the peak summer holiday period in Europe (August) and the solar eclipse on 11 August 1999, the World Health Organization (WHO) launched in Geneva today an information campaign "Solar Alert '99" to signal possible adverse health effects of solar radiation.

The UN agency warned about significant dangers from overexposure to the sun, as well as from direct viewing, without adequate protection, the forthcoming solar eclipse. This solar eclipse will be the last total solar eclipse of the millennium as well as the first in nearly 40 years that will be visible from Europe.

"The lens of the eye acts as a magnifying glass," explained Dr Bjorn Thylefors, Director, WHO Programme on Disability Prevention. "It produces tiny images on the retina of what we are viewing, with a concentration factor of about 10 000. During direct viewing of the sun, for even a few seconds, the light entering the eye is concentrated to the point that it can burn the cells of the retina. Thus, the cells are destroyed and that part of the retina becomes blind".

WHO cautioned against relying on any unmarked filter to watch the forthcoming eclipse. It also warned against the use of sunglasses, exposed film or smoked glass and called these devices "unreliable". "If you have no protective devices, do not yield to the temptation to view the 1999 solar eclipse. Your eyesight is much more important," stressed Dr Thylefors.

In Solar Alert '99, the World Health Organization also warned that overexposure to solar radiation (sunlight) could have serious health consequences for the skin, eyes and immune system.

Solar radiation is strongly associated with a number of chronic skin conditions, including various skin cancers of which melanoma is the most life-threatening. According to the United Nations Environment Programme (UNEP), more than 2 million non-melanoma skin cancers and 200,000 malignant melanomas occur globally each year. In the event of a 10% decrease in stratospheric ozone, which protects the Earth from ultraviolet rays (UV), an additional 300,000 nonmelanoma and 4,500 melanoma skin cancers could be expected worldwide annually. Caucasians have a higher risk of skin cancer because of the relative lack of skin pigmentation.

The Global Solar UV Index provides an estimate of the maximum solar UV exposure at the Earth's surface at solar noon. on any given day. The values of the Index range from zero upward and the higher the Index number, the greater the likelihood of skin and eye damage. In the most extreme environments close to the equator, summer-time values can range up to 20. During a European summer the Index is generally not more than about 8, but can be higher, especially at beach resorts. The following descriptions are usually associated with various values of the Index: Low UV exposure - 1 and 2; Moderate exposure - 3 and 4; High exposure - 5 and 6; Very high exposure - 7 and 8; Extreme exposure - greater than 9.