Written by DAN Staff
In the first metre/three feet of a descent, a diver’s ears are subject to a 10 percent increase in ambient pressure. At two metres/six feet, it’s a 20 percent increase. At 3 metres/10 feet the pressure is sufficient to cause blood vessels to burst and fluid and blood to be drawn into the middle ears. Despite the noticeable change in pressure, many divers don’t equalize their ears earlier enough upon descent. Injury statistics show that ear injuries are one of the leading problems divers face – even though preventable with proper equalization. As an instructor, you have the opportunity to help divers avoid ear injuries by firmly establishing the importance of equalization early in their training.
Take a moment to brush up on your knowledge of ear injuries so that help improve your student divers’ comfort in the water – now and for the rest of their diving careers.
Rupture of a tympanic membrane (eardrum) is generally the result of a failure to equalize the air-filled middle-ear, or from a too-forceful Valsalva maneuver. The condition is often painful and vertigo may follow, although the rupture may relieve the feeling of pressure in the ear. Most perforations will heal spontaneously within a few weeks, although some cases may require surgical repair. Perforations allow water to enter the middle ear, which creates a significant risk of infection. Thus, evaluation by a doctor is crucial. Congestion, inadequate training and descending too fast can increase a diver’s risk of eardrum perforation.
Like an eardrum perforation, inner-ear barotrauma can be caused by a failure to equalize or by an aggressive Valsalva maneuver. A significant differential between the ambient pressure and the pressure in the middle ear can cause an outward bulging of the round window of the inner ear. This can lead to symptoms even in the absence of a rupture. Divers with inner-ear barotrauma may experience severe vertigo, hearing loss, tinnitus, a sensation of fullness in their ear and involuntary eye movements known as nystagmus. Should the round window rupture, the loss of fluid in the inner ear can damage the hearing and balance organs and surgical repair may be required.
Middle-ear barotrauma is a condition in which pressure in the middle-ear space is significantly lower than the pressure outside of the ear. This results in a relative vacuum that causes the eardrum to bulge inward and the tissue of the ear to swell. Fluid and blood from ruptured vessels leak into the middle ear. This can be caused by a failure to equalize or an obstruction of the Eustachian tubes (usually by mucus) during descent. Divers with middle-ear barotrauma generally report initial discomfort, which can intensify to severe pain, and ears that feel clogged or stuffy.
Facial baroparesis is the reversible paralysis of the facial nerve due to increased pressure in the middle ear. In some people this pressure can impair circulation to a facial nerve that’s located close to the ear. This can happen while flying or diving, and symptoms usually include numbness, tingling, weakness and paralysis of the face. 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 about ear injuries and safe diving practices, visit DAN.org