Page 54 - AlertDiver_Winter2013

Q:Six weeks ago I had surgery for a detached
retina. Will I still be able to dive?
A:The retina is made up of several layers of highly
organized light-sensitive cells that line the
interior surface at the back of the eye. Its ability
to gather light and transmit visual signals to the brain
is integral to vision. Retinal detachment compromises
this critical function and may result in impaired vision
or blindness. Detachments are typically painless, and
many are associated with warning signs such as flashes
or visual spots.
Retinal detachment is a separation of the layers of
the retina from the underlying cells and structures.
The most common type of retinal detachment occurs
when the vitreous body in the middle of the eye exerts
traction on the retina and creates a break that allows
fluid to accumulate between the retina and the retinal
pigment epithelium.
Various procedures are used to repair retinal
detachments. One of these, pneumatic retinopexy,
involves the injection of gas into the eye. Individuals
who have had a gas bubble placed in their eye should
get confirmation from their ophthalmologist that the
gas bubble is gone before diving, flying or ascending
into mountain regions. An intraocular gas bubble can
cause severe eye pain and permanent loss of vision
if the individual is exposed to significant changes in
ambient pressure.
Some other
surgical procedures
involve removal of
the vitreous fluid and
replacement with
silicon oil, which
remains in the eye
until it is removed at
a later date. Diving
may not be advisable
following this type of
procedure because
it is normally used
in the repair of very
complicated retinal
detachments, and a
second surgery may
be necessary. Such
cases require close
communication with
your ophthalmologist.
Regardless of the type of procedure, adequate healing
time is needed prior to a return to diving. Ophthalmologists
recommend waiting two months after retinal detachment
surgery before diving, even if all gas is gone before then.
Once a gas bubble is gone and healing is complete, there is
no reason that diving would constitute a risk to the retina or
visual acuity.
— Lana Sorrell, EMT, DMT; Nick Bird, M.D., MMM
(with special thanks to Frank Butler, M.D.)
Q: I understand that strenuous exercise after
diving is generally not recommended. What,
exactly, does “strenuous exercise” mean?
A:Defining “strenuous exercise” simply is difficult.
Describing a fixed (or absolute) intensity
threshold is not feasible since the impact of any
absolute effort will vary between individuals, primarily
as a function of body size, body composition, physical
fitness and economy of effort (that is, some individuals
can do the same task with much less effort than others).
Describing a relative intensity threshold indexes the
strain to the fitness level of the individual but this, too,
is imperfect, since the potentially large differences in
absolute work between the very unfit and the very fit
can play a role.
The challenge of definition means we have to stick
to generalities. Exercise that employs high joint forces
such as running or heavy gear lifting should be avoided
52 | WINTER 2013
RESEARCH, EDUCATION & MEDICINE // F R O M T H E M E D I C A L L I N E
STEPHEN FRINK