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Chapter 32 — 1
Chapter 32
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MISCELLANEOUS
DISORDERS
CONTACT LENSES
Contact lenses are a convenient alternative to spectacles but can be a source
of problems to the diver. The most common of these is
loss
of the expensive
lens during removal of the face mask. The eyes should be shut while
removing the mask underwater or on the surface.
In certain circumstances, especially during long or deep dives or in
compression chambers, it is possible for
gas bubbles
to form behind the
contact lens (particularly with hard, non gas-permeable lenses) causing
pressure and damage to the cornea of the eye. If this happens, the diver may
experience discomfort in the eye, blurred vision and the appearance of halos
around bright lights. Long term effects could include scarring of the cornea.
Gas bubble damage can be overcome in the hard contact lens by an optician
drilling a small hole in the centre of the lens (a
fenestrated
lens) which allows
gas bubbles to escape. This has no effect on the visual performance of the
lens. Soft contact lenses are usually not a problem because of their gas
permeability and flexibility.
It is now relatively easy to have corrective lens ground into or attached to the
diver's face mask, as an alternative to contact lenses (see Chapter 5).