Medical Column

Eye protection methods in high-luminosity situations We wish to express our thanks to the author of this article, the Spanish doctor Pilar Gómez de Liaño, who offered her ophthalmological services at the recent European Blind Skiing Championships, held in Baqueira Beret. On this occasion, she steps up to our Medical Forum in order to offer some reflections and put forward several pieces of advice with respect to the ocular effects produced by exposure to high degrees of luminosity - a subject very closely linked to the practice of competition skiing - and the advisability of using some kind of filter as a preventive measure. Last January, I had the chance to attend the II European Alpine Skiing Championship for the blind and visually impaired. My presence as ophthalmologist was a result of the need to classify the athletes for the different categories according to their degree of disability (B1, B2 or B3). During the competition, some of the participants - and other members of the distinct delegations - suffered ocular problems, due to inadequate or zero protection. This fact caused me to reflect upon the information that we, as health professionals, should be making public. Sunlight is defined by three wavelengths: ultraviolet, visible and infrared. The effects of ultraviolet radiation (UV) on the skin have been the object of numerous studies and conclusions. Ever since the hole in the ozone layer was discovered, practically all the reports advise us to use the maximum protection possible to avoid the dangers that such exposure could cause in our system. Ultraviolet radiation is catalogued in three categories: a.- UVC, from 100 to 280 Nm b.- UVB, from 280 to 315 Nm c.- UVA, from 315 to 450 Nm UVC is normally absorbed by the ozone layer of the atmosphere and UVB (up to 300 Nm) is absorbed by the cornea. The rest - part of the UVB and the UVC radiation - penetrate the eye up to the crystalline lens. Under normal conditions, both acute and chronic exposure to UV radiation can also cause alterations in the different structures of the eye. These phenomena may even be aggravated when the person is in a place where there are bright reflections (in the sea, up a mountain or in snow) or if that person suffers from some ocular affection (such as aphakia, albinism, etc.). As ophthalmologists, we must inform the general public of the dangers that may be produced by prolonged exposure and, in addition, prevent the occurrence of certain injuries with all the means at our disposal. The principal element in ocular protection are glasses. Nowadays, all - or practically all - lenses or contact lenses incorporate molecules, introduced during manufacture, that absorb the ultraviolet rays. Nevertheless, there exist some filters on the market that absorb beyond the limits considered dangerous for the eye (400 Nm) as they are capable of neutralising up to 450 Nm. These lenses also permit a reduction in the glare effect, and increase the sharpness and contrast of the image without modifying the natural perception. This kind of filter guarantees a high level of solar protection and are therefore particularly suitable for those persons who are frequently exposed to solar radiations, or suffer certain pathologies such as aphakias, macular degenerations, aniridias, albinism, etc. Apart from the essential corrective lenses, it is recommended that skin protection creams be used and, in certain cases, a hat may reduce the luminosity that reaches the eyes. Therefore, any kind of glasses include some filter incorporated in the lenses that protects our eyes from ultraviolet radiation; however, for those with particular problems, or for those who are especially hypersensitive to the sun, protection can be greatly increased by using filters which absorb a greater degree of radiation. Dr. Pilar Gómez de Liaño "Gregorio Marañón" University General Hospital Madrid (Spain)