Written by DAN Staff
In the first metre/three feet of a descent, your ears experience 10 percent greater pressure than they did at the surface. At two metres/six feet that percentage doubles, and at three metres/10 feet, there’s enough pressure differential to rupture ear drums, or burst blood vessels and draw fluid and blood into the inner ear.
Despite the fact that most ear injuries can be prevented, many divers seem to equalize their ears almost as an afterthought. Injury statistics show that ear issues are one of the leading causes of dive injuries. You can help reduce you student divers’ risk of an ear injury by firmly establishing the importance of equalization early in their training and continually reinforcing the need to equalize before any discomfort occurs.
Ear injuries can occur quickly, so take a moment to brush up on your ear injury knowledge to help improve your divers’ safety and comfort.
Middle Ear Barotrauma
A middle-ear barotrauma is a condition in which pressure in the tympanic cavity (air-filled space in the middle ear) is significantly lower than the pressure outside the ear. This results in a relative vacuum that causes the eardrum to bulge inward, ear tissue swells, and fluid and blood from ruptured vessels leak into the tympanic cavity. This can be caused by a failure to equalize or Eustachian tube obstruction on descent. Divers with middle ear barotrauma will generally report initial discomfort that may intensify to severe pain, and the feeling of clogged, or stuffy ears.
A rupture of the tympanic membrane (eardrum) is generally the result of a failure to equalize the middle ear, or too forceful a Valsalva maneuver. The condition often causes pain, although the rupture may relieve the feeling pressure on the ear, and vertigo may follow. Most perforations will heal naturally within a few weeks, although some cases may require surgical repair. Factors like congestion, inadequate training, and excessive descent rates can increase a diver’s risk of eardrum perforation.
Inner Ear Barotrauma
Similar to eardrum perforation, inner-ear barotrauma can be caused by a failure to equalize or an inappropriately aggressive Valsalva maneuver. A significant pressure differential between the external and middle ear can cause an outward bulging of the ear’s round window. This can cause inner ear injuries without a rupture. If the round window ruptures, the loss of fluid in the inner ear can damage the balance and hearing organs, and surgical repair may be required. Divers with inner ear barotrauma often experience severe vertigo, hearing loss, tinnitus (persistent noise in the ears), a feeling of fullness in their ear, and involuntary eye movements known as nystagmus.
In some individuals, increased pressure in the middle ear can stop circulation to a facial nerve resulting in facial baroparesis – paralysis of the facial nerve. This reversible condition can happen while flying or diving, and symptoms usually include numbness, tingling, weakness and facial paralysis. Facial droop can sometimes be seen and can cause concern, but facial baroparesis often resolves spontaneously. Divers who exhibit symptoms of facial baroparesis should seek medical attention to rule out other serious conditions.
For more information on ear injuries and safe diving practices, visit DAN.org