| Since the human eye is not designed to see in water, | | | | making this type of mask harder to equalize or clear. |
| anyone who enters the sub-aquatic realm must wear | | | | The solution was provided by the first low-profile |
| a facemask in order to see; the reason for this is | | | | scuba masks; whereas masks before this had been |
| that the optical density of water is completely | | | | worn over the eyes and nose, low-profile masks |
| different to air for which the eye is designed. | | | | featured a nose pocket below the lens that allowed |
| Allowing for an air gap between the eye and the | | | | the glass to be closer to the eyes, reducing the |
| water overcomes this limitation - we can focus | | | | volume of air contained within the mask,. |
| underwater and vision is restored. | | | | Another difference in scuba mask design is in the |
| A scuba mask is a relatively simple device, consisting | | | | material of the skirt; originally this was made from |
| of a glass lens, a rubber skirt that seals against the | | | | neoprene, but silicone has been used since the 1980s; |
| face and a strap to fasten it. The original face masks | | | | it is more comfortable for the diver due to its |
| were often crudely fashioned at home from a piece | | | | greater flexibility and longer lasting because it is less |
| of circular glass and bicycle inner tube, but by the | | | | susceptible to damage from sunlight. |
| end of the 1950s mask design was beginning to | | | | Modern scuba masks generally consist of a |
| evolve from this circular design to an oval, allowing | | | | lightweight plastic frame, glass lenses and a silicone |
| for a wider field of view. | | | | rubber skirt. It is interesting to note that although |
| A further development in the 1960s occurred when | | | | silicone can be translucent, the skirt on modern scuba |
| two panes of glass were added to the sides of | | | | masks is often coloured black, just as with the |
| scuba masks, further increasing peripheral vision but | | | | original neoprene masks. |
| with the side effect of increasing internal volume, | | | | |