A dive mask is essentially the one piece of equipment that gets you interested to go scuba diving because you want to see everything there is to see while being underwater. The rest of the scuba equipment is supportive of allowing a diver to stay underwater that much longer. When looking for a scuba dive mask there are a few things that should be considered to ensure your safety and comfort.
The size of the mask as it relates to fit is very important. Underwater pressure will help seal the mask that is a little loose around the edges, but it is better to err towards safety and look at a smaller size that fits comfortably in order to make a proper seal around the edge. Facial features also play a part in determining the size, as large features such as a protruding nose bone will mean a larger mask size.
Another consideration is the amount of air space or "volume" around the eyes. The larger masks have more air space and some even have side glasses to aid in the peripheral vision of the diver. The smaller sized masks though are lighter and easier to clear the water from.
Masks are made as either a one-piece model or as multiple pieces that are held together usually with silicone, also called a "frameless" mask. The one-piece allows for a complete and unobstructed view while diving and is made of translucent silicone. The frameless mask allows for the lenses to come out and be replaced if needed. This is especially preferred for the diver with prescription eyewear as prescription lenses can be specially made by an optometrist to fit the mask.
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