There are several essential factors in a successful dive. Breathing, of course, is paramount. Keeping warm is another but, depending on where you dive, that may often take care of itself. However, no matter where you dive, visual acuity is very important. Seeing well means keeping you safe and allowing you to enjoy all that diving has to offer – the colorful plants and fish, the splendid variety, the aspects of our world so interestingly different from the land. To accomplish that, you have to know how to keep your mask clear. Even well-fitting masks can fog, take in water or even fall off while on a dive. Here’s what to do before you go under, and during your undersea adventure to keep your mask in optimal condition.
Obscuring the faceplate glass can happen any one of several ways. Small droplets of water can condense on the interior of the faceplate as a result of sweat off the forehead and the skin from cheekbones. Sometimes there’s a small amount of leakage through the mask and the droplets get bounced onto the inside of the glass. But the most common cause is exhalation through the nose of hot, moist air. When hot, humid air hits the inside of the cold faceplate glass the effect is the same as that of a car windshield on a cold day. It fogs up. Moist, warm air condenses into small droplets and visual acuity is decreased. The old saying ‘an ounce of prevention is worth a pound of cure’ is worth remembering here. Before you submerge, coat the interior of the faceplate with a thin layer of material that will disperse the droplets as they start to form. That material can be anti-fogging spray from a commercial dive shop. Or, it could be any one of several home recipes developed by experienced divers over decades. Raw potatoes have a starchy liquid that works well, for example. Cut a potato in quarters and smear the flat surface over the glass just before going under. Then rinse the mask lightly and put it on. Don’t have any potatoes? Try baby shampoo or some other tearless shampoo. Squirt a tiny amount on two fingers and spread it around, then rinse, but not enough to wash it off. As a last resort, spit will do. The drawback is that spit isn’t most individuals’ idea of something pleasant to have close to the eyes. It also tends to attract bacteria and washes off too easily. But, it’s better than nothing.
Once you’re under, if a small amount of moisture gets into the mask through the boundary (the skirt edge) that too can be dealt with easily. Here are some easy to follow tips.
As you sense water enter the mask, inhale through the mouth and – though it isn’t the standard breathing technique – exhale sharply through the nose. Some divers will tilt the bottom of the mask out slightly AT THE SAME TIME as they exhale. That’s tricky and can result in letting even more water in. Usually a good snort will clear the mask. Repeat as needed. If your mask fogs, but you’ve prepared it as above, it should clear in a few seconds. As a last resort, you can surface and take care of the problem, but that costs dive time that most scuba enthusiasts won’t want to sacrifice.
If this does not help and your mask is still foggy while underwater, then you can let a small amount of water into the mask and slosh it around from side to side to clear off the fog. You can periodically continue do so, every time the mask gets a bit foggy. This is not an ideal situation, but it does allow you to stay on a dive and see some interesting sea creatures
Be sure to keep your mask clear as much as possible. Your safety depends on being able to judge potential dangers underwater. It also allows you to see everything you took all the trouble to go down to experience.