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Gear tips: Gauge Reader Masks

Are you:

If you answered yes to all the above, then you probably have presepobia, a condition where the eye exhibits a progressively diminished ability to focus on near objects with age.

On the surface the fix is reading glasses (those things you always forget just when you need them most). Bright light also helps, as it constricts the pupils, and decreases spherical aberration. Some people use bifocals, trifocals or multifocal lenses.

Under water the solution is a "gauge reader" mask. A gauge reader is a normal mask with magnifying inserts which cover about 1/4-1/3 of the mask. The inserts are placed at the bottom, or the bottom inside of each glass plate. Typically the magnifying insert is +2 dioptres.

What is a dioptre? For people with presbyopia and normal distance vision a +1 dioptre lens focuses the eye at one metre, a +2 dioptre lens focuses the eye at 1/2 metre, and so on.

People with myopia (short-sightedness) typically use negative dioptre lenss, but they don't use gauge reader masks.

So the typical gauge reader mask has a +2 dioptre insert lens at the bottom inside which focuses your eyes conveniently at 0.5 metres from your face when you look down, but when you look up you are seeing things normally (a bit like bifocals). Half a metre is an excellent distance for reading gauges and looking at your underwater camera. There are weaker gauge readers available, typically +1.5 dioptre, but there is not much point in buying them, as your eyes will inevitably change and within a few years you will need the stronger +2 dioptre insert.

Glass inserts
Glass Insert, +1.5 dioptre.

Glass gauge reader inserts are very thick, look ugly, and can be a bit confusing as you have a great big line right in front of each eye. However, they can be cleaned with toothpaste or anything else that you clean your mask with.

Sea Vision 2000
Sea Vision 2000, +2 dioptre.

Hard plastic gauge reader inserts can have a higher refractive index, and so can be thinner, and moulded so that they are hardly noticeable, and the transition between the insert and the normal lens does not seem to interfere with vision so much, however, they should not be cleaned with toothpaste.

The best gauge reader masks that I have come across so far are from SeaVision. They are called "Gauge ReaderT +2.00 lenses. They come in 3 sized masks:

SeaVision also do custom prescription masks (single and bifocal) over the internet, if you can specify your prescription. As at September 2008 the standard mask costs US$65, and a gauge reader costs US$210, with shipping to Australia around US$15.

There's also an Australian manufacturer in OzBob SCUBA, who boast 30 years experience.

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