The everyday dangers of the sun

The risks begin at sunrise, and all the more so when the sky is clear. A simple walk through the streets of your town at midday exposes your eyes to ultraviolet rays. Beware of reflections off white façades and mirror-glass buildings... Construction workers, farmers, and generally all people working outdoors, in town or in the country, are exposed to radiation and should wear protection as often as possible. 

Likewise, people working in professions exposed to high levels of sunlight combined with light reflection (lifeguards, fishermen, etc.), or to artificial lights with high UV content (photographers, people working in certain laboratories, etc.) must absolutely protect themselves. It is worth highlighting the dangers to the skin and eyes in artificial tanning booths, where medical supervision is unfortunately rarely offered.

The dangers during the holidays

Outdoor holiday periods are, by far, the most risky periods for the eyes. However, it all depends on the location, the season, and the climate. While in the countryside, in a shaded and cool spot, the eyes are exposed to little UV damage, the same cannot be said for the mountains in winter, or the seaside in summer. 

In the mountains

Solar radiation there is extremely high in winter, as snow reflects 85% of UV rays. 

Furthermore, for every thousand metres gained in altitude, the proportion of ambient UV rays increases by 10%. Consequently, the impact on the eye can only be greater.

The ophthalmological conditions particularly associated with stays in the mountains are:

Most commonly, "snow blindness". Already mentioned above, it affects the cornea. It can occur from the very beginning of the stay, or the following day. It is not a reaction to the snow itself, but to the ultraviolet rays it has intensely reflected onto inadequately protected eyes.

An unpleasant sensation of "sand in the eye", redness, pain, tears, sensitivity to light — it's all there. This keratitis will heal with treatment, but it can also become chronic if it recurs during subsequent stays.

Linked to atmospheric conditions — cold, fog, and altitude — the "white out" syndrome affects off-piste skiers and ski tourers. It involves frostbite of the eyes and eyelids, accompanied by reduced vision, watering, pain, and sensitivity to light. It can also cause a loss of perception of relief and sense of direction along with dizziness, which are particularly dangerous given the constant hazards of off-piste skiing.

High-index, wraparound protective sunglasses, of the glacier goggle type, prevent this dangerous syndrome. In summer, ultraviolet radiation is better absorbed by the ground. However, on glacier treks as well as in climbing, the risk remains significant at altitude.

By the sea

The highest-risk locations are the beach and boats. Sand reflects 10% of rays (the same applies to the desert), while water reflects around 20% depending on its calmness (the same applies to lakes and rivers). Climate plays a significant role through the degree of humidity: the drier and hotter the air, the more dangerous the radiation.

Tropical holidays in winter require redoubled precautions: within a few hours by plane, one travels from low-light northern climates to sun-drenched destinations. Be good to your eyes! Don't hesitate to use solar lenses!

How do we protect our eyes?

The sight in question

A tinted lens stops visible radiation and protects against glare, but, if it is not filtering, it does not stop the invisible UV rays, which then flood the eye dangerously. 

To protect the eye from harmful radiation, it is necessary to filter it — that is, to selectively block those rays that are damaging.

A filter will absorb part of the energy of the radiation, making it "less intense". Depending on the material it is made of, it can alter the spectral profile of the light passing through it. For example, it absorbs all wavelengths below 350 nm. If, in addition, the filter is tinted in the mass, it absorbs even more. It can also be treated with a mirror finish. These are the main characteristics of sunglasses. Today, ophthalmic lens manufacturers offer very comprehensive ranges. 

Corrective lenses also filter UV rays. The UV cut-off (or filtering power) of a lens is not related to its tint, but depends on the material from which it is made. As a result, some corrective lenses can filter out all ultraviolet rays, whereas a poor-quality solar lens offers only minimal UV cut-off.

Today, three types of materials are available (mineral, organic and polycarbonate), each with its own filtration characteristics. These clear corrective lenses can also have an additional tint, helping to reduce brightness and prevent glare. You thus have access to solar lenses adapted to your prescription and offering a high level of protection. Finally, a specific anti-ultraviolet treatment is available on organic lenses. This type of treatment is perfectly suited to those seeking protection above the standard level. 

Not all contact lenses are equipped with a UV filter. When they do feature one, they offer good protection against photo-trauma caused by ultraviolet radiation. In certain cases of very significant or repeated exposure, this protection must be supplemented by wearing filtering sunglasses.