Pressure plays a big roll in scuba diving and one of the serious effects of pressure is Ear Barotrauma. Pressure is everywhere around a scuba diver. There is pressure in the air, the water, your air tank, body cavities, your BCD, all are impacted by pressure so it is really a good idea to have some knowledge of what pressure can do.
Ear barotrauma or Middle Ear Barotrauma are both caused by the pressure of the surrounding water against your tympanic eardrum. The effect is quite painful and can cause permanent deafness if a diver is not careful.
Most people have all heard of “The Bends” but you do not hear much about Barotrauma or Ear Barotrauma very often. So this is just a little education about one of the effects of pressure on a diver, specifically the ears.
At The Surface
At the surface of the water or sea level, the pressure outside of the ear and inside of the ear are equal at 1 ATA (atmosphere) or 29.4 psi (pounds per square inch). This is because the inner ear is open to the atmosphere via the Eustachian tubes and your airways.
Once you begin to descend the pressure outside will increase and it will become necessary to equalize the pressure between the water outside of the eardrum and the middle ear. It should be noted that the biggest pressure changes occur close to the surface of the water in the first few feet so equalize often.
To equalize the pressure that builds up, pinch your nose closed and blow air gently into your nose. You will feel a slight “pop” in your ears when the pressure equalizes. This is called the Valsalva Method.
A diver that is floating on their stomach on the surface just has to bend down at the waist and their head will be at about 3 feet. At this depth, the pressure on the outside of the eardrum will have increased to 10% of that at the surface, just from bending at the waist. Half of your body is still on the surface.
At this depth, the eardrum will begin to bulge inwards causing you to feel a slight pressure in your ear as the volume of the middle ear is reduced.
At six feet, the pressure on the eardrum will have increased to 20%. If the diver has not equalized at this point you will begin to experience pain.
At this depth, the eardrum will bulge inward stretching the tympanic membrane and the nerves in it which will send out a signal to the brain, which is why you will experience pain in your ears.
Beyond six feet at roughly 2 – 2.25 meters if the diver still has not equalized the eardrum will begin to reach its maximum limit of deformation. The pain will become really intense at this point
Blood vessels and tissues in the middle ear will begin to tear which can leave serious bruising that can last up to 3 weeks. Also, the Eustachian tubes will be squeezed shut making it almost impossible to equalize the pressure.
At ten feet, if the diver has not equalized or the eardrums have not ruptured yet, fluid from the torn tissues and broken blood vessels will be drawn into the middle ear. This is known as Middle Ear Barotrauma.
The diver will experience a slight decrease in pressure and pain but the damage done will take a while to heal. Also, the fluid that builds up will take about a week for the body to absorb.
Beyond ten feet and the eardrums will completely rupture. The pain will be excruciating and the middle ear will fill with cold water. The cold water, when it reaches the balance mechanisms in the vestibular canals, will cause the diver to experience massive vertigo and will lose all orientation in the water.
So as you can see the pressure effects close to the surface are at their greatest and only takes ten feet to destroy your ears so be sure to always equalize often as you descend.
Some Final Thoughts
Ear Barotrauma can really cause serious harm to you and you should always be aware of it. Listen to your ears as you dive. If they feel a slight pressure increase then go ahead and equalize by holding your nose and blowing gently into your nose.
On ascent, the pressure will decrease and your eardrums will flex in the opposite direction as the pressure inside the ear will be greater than the pressure outside in the water. Just swallow and move your jaw around and the pressure inside the ear will be released and the feeling will go away. Do this all the way to the surface and you will be fine.
If you are interested in learning about the other effects pressure have on divers then just click this link to my Pressure and Scuba Diving article.
If you have any comments or would like to share an experience with ear barotrauma, I would love to hear from you. Just leave a comment below and I will be happy to respond to you.