Scuba Diving Masks

Scuba Diving Masks
Scuba diving masks are a deceptively simple piece of diving equipment. Although they seem to be little more than goggles, they are in fact essential to proper safety underwater. The human eye cannot focus correctly underwater because water causes the light entering the eye to be refracted differently. Masks correct this and allow better visibility on a dive. As well, many people feel very uncomfortable and even panic when water gets into their eyes. A scuba mask prevents this as well.
All scuba masks have one or more lenses, a strap which fits over the crown of the head, a nose pocket, and a skirt. Scuba diving masks, however, vary widely in style and the new diver can quickly can become overwhelmed. As well, some masks have additional features. For example, some masks come with a snorkel attached or built-in. Savvy divers generally avoid these masks – they tend to be of lower quality.
When choosing the right scuba diving mask for you, consider:
1) Lenses. Always look for safety lenses made from tempered glass. Tempered glass lenses will resist breaks and scratches, which is vital when you are underwater. The last thing you want is broken glass from your lenses flying towards your eyes because you didn’t have tempered glass. In addition to tempered glass, look for lenses that are crystal-clear and have no blemishes or flaws – any flaws can seriously affect your vision underwater.
2) Fit. A mask must fit correctly on your face in order to correctly seal out water and protect your eyes. Scuba diving masks come in basic sizes: small, medium, and large. However, the design and style of different masks make them fit in dramatically different ways, which is why you will want to try on a variety of masks before finding one that is perfect for you. To determine whether a mask fits, put your snorkel or regulator in your mouth and place the mask over your face without securing it with the strap. Take a breath in through your nose but don’t exhale. Let go of the mask. If the mask falls of, it is not a good fit. A correctly fitted mask will remain on your face when you let go. If you have facial hair, however, you will need to apply some silicone compound to your beard or mustache before you do the test. This is the only way to see whether the mask will create a proper seal on your face.
3) Skirts. Skirts are the layer of silicone or other substance which creates a seal with your face when you are underwater. Most of the time, modern scuba diving masks have hypo-allergenic silicone skirts. If you have sensitive skin, you may want to double-check that your mask’s skirt is, indeed, hypo-allergenic. Beyond that, you will need to choose skirt color, which is not just about fashion. Light-colored mask skirts can increase your peripheral vision and allow more light in. For new divers, this is often ideal as it allows for a more “natural” visibility. Photographers, however, often favor dark-colored mask skirts, precisely because they do limit light and allow a diver to focus on what is immediately in front of him or her.
4) Mask straps. Mask straps can be made from silicone, neoprene, or rubber. In general, silicone and rubber straps are good for cold-water dives because they are easy to adjust even if you are wearing gloves. They also tend to stay in place better in cold temperatures than neoprene straps. For warm-water dives, however, neoprene straps can be ideal if you don’t want your hair getting caught in your mask strap. 
5) Nose pocket. The nose pocket of your mask should not feel tight and should fit over your nose comfortably. The nose pocket should let you pinch your nose easily. This is important if you want to clear your ears while diving.
6) Lens numbers. Scuba diving masks can come with one lens, two lenses, or even up to six lenses. A higher-profile mask with more lenses will allow more water in and will take longer to clear than a lower-profile mask. As well, higher-profile masks will create more drag under water. However, masks with bottom and side lenses can improve your peripheral vision and can allow you to check your gear more easily. They can also allow you to enjoy the sights around you at depth a little bit more. To determine how many lenses you feel comfortable with, try on many types of diving masks. Consider, too, that if you have a smaller face or might be distracted by a larger field of vision, lower-profile masks and single lens masks may make you more comfortable.
7) Corrective lenses. Some scuba diving masks allow you to fit prescription lenses inside them, which is important if you wear glasses. Of course, masks allow you to wear contact lenses under water, but keep in mind that if you need to remove or replace your mask underwater, you will need to keep your eyes tightly closed if you wear contact lenses on a dive. In addition to corrective lenses, some masks come with special features to improve visibility. For example, double-dome masks make up for the fact that the human eye sees objects closer and larger underwater. Wearing double-dome masks allows you to see more normally and may correct some myopic vision.
8) Purge valve. Some scuba diving masks come equipped with a one-way purge valve. Located in the nose pocket, the purge valve makes it easy to clear your mask. If water gets in your mask, you can simply exhale through your nose and the valve will clear the mask. However, not all divers like the one-way purge valve. If sand or grit enters the one-way purge valve, your mask might leak.