If there's one season that is particularly drying to eyes and skin, aside from summer, it is winter. In summer, body surfaces are assaulted by solar radiation, allergies, air conditioning and perspiration. In winter, you have forced-air heating, too many hours indoors, not enough vitamin D ("the sunshine vitamin"), weather inversion layers causing increased air pollution, cold winds and lower humidity.

Why is the humidity lower in winter? "Humidity" refers to the number of droplets of water floating in the air. The more droplets, the higher the humidity. The TV weather person, however, talks about "relative humidity." That refers to the fact that as the temperature rises, the amount of humidity the air can hold increases. So 100% humidity at 100 degrees is far more humid than 100% humidity at 50 degrees. Even in the American West, with its arid summers and soggy winters, summers are more humid than winters even though the relative humidity is often higher in winter. Skin and eyes require humidity to remain moist and healthy, provided the humidity is unpolluted. Polluted humidity droplets lose their moisturizing benefit because most pollutants are desiccants (drying agents).

Why is forced air-heating bad for you? The air from your furnace tends to be as dry as the Kalahari desert, and the hot-wind sucks moisture from your body. Your heating system also circulates airborne bacteria and fungal spores, which are also dehydrating. These critters are especially abundant in winter because people tend to keep windows closed and their house becomes like a terrarium.

Before you drive yourself crazy with worry about all this, be assured that your body has defenses. The point of taking extra precautions is to give yourself an edge so you will not only endure the winter but thrive with radiant health.

Some winter moisturizing suggestions:

• Keep a window open somewhere, preferably in the bathroom or bedroom.
• Change furnace filters regularly.
• Set out bowls of water around the house.
• Wash hands and clean household surfaces regularly.
• Drink plenty of water (start each day with eight ounces of warm water).
• Avoid fluorescent lighting if possible.
• Take a slow, lingering bath or shower every day. Breathe deeply and relax. If you take a bath, follow it with a quick shower to rinse away the bath residue and get bacteria off your skin.

Bio-Logic Aqua Technologies Biomedical Research makes two products that help restore lost moisture to skin and eyes in winter. They are NATURE'S TEARS^® EyeMist^TM and NATURE'S MIST^® skin water. Apply NATURE'S TEARS^® first thing in the morning to get rid of bleary "morning eyes", and during the day whenever eyes feel dry, tired or irritated and need a burst of fresh, humid air. NATURE'S MIST^® should be applied after facial cleansing, just before applying a moisture sealer and any time your skin feels dry, itchy or uncomfortable.