Equalize: Early and Often

What is the most common scuba diving injury??

Decompression sickness? Cuts from coral reefs? Animal attacks?

Me holding a sea cucumber. Also pictured: scuba buddy, Zorg. Catalina Island, CA. 

No, in fact, the most common injury is of the EAR.

From swimmer’s ear to barotrauma, ear injuries are frequent but preventable with an increase focus on ear anatomy and awareness of what could go wrong.


The most common type of ear injury is a barotrauma, or an injury related to pressure. Just like the pressure you experience in an airplane, scuba divers feel the same pressure on their ears as they descend in the water. This pressure occurs because the air pressure of the middle ear is not equal to the pressure of the external environment. The middle ear consists of three bones (called the ossicles), which are suspending in an air-filled space. This space is connected to the external environment by a thin omiddle-ear-pressurepening called the Eustachian tube. The Eustachian tube, which connects the middle ear to the back of the throat, it normally closed. Scuba divers are overly aware of the Eustachian tube, as they are taught to “equalize early and often”. Equalizing the ears acts as a preventative measure to make sure the pressure of the middle ear and the external environment are always equal.


How do I equalize?


To open the Eustachian tube, or “equalize”, you can swallow, move the jaw or perform the Valsalva maneuver. The Valsalva is a common technique for scuba divers, completed by pitching your nose and exhaling forcefully with a closed mouth. These procedures will cause air from your throat to enter the middle ears. You may hear a soft pop or click when this happens.


Why should I equalize?


The first 14 feet (beginning of the dive) is where the ear is most at risk because of the rapid relative gas volume change. If you do not equalize on your descent, here is what happens:

  • At one foot below the surface:
    • The water pressure outside of your eardrums is 0.445 psi more than in your middle ears. The eardrums flex inward.
  • At four feet:
    • The pressure difference is now 1.78 psi. Your eardrums bulge into your middle ears. The round and oval windows between the middle and inner ears also bulge in. Mucus begins to fill your Eustachian tube. You begin to feel pain and it is very difficult to equalize.
  • At six feet:
    • There is a 2.67 psi difference. Your eardrum stretches further and its tissues begin to tear. Small blood vessels in your ear may expand or break. Your Eustachian tube is locked shut by the pressure in your middle ear, making it impossible to equalize. Pain increases.
  • At eight feet:
    • There is a 3.56 psi difference. Middle-ear barotrauma occurs causing blood and mucus to fill the middle ear. Fluid (not air) equalizes the pressure on your eardrums. Pain subsides but there is a feeling of fullness in your ears that remains for over a week.
  • At ten feet:
    • The difference in pressure is 4.45 psi. It is possible that your eardrums could perforate, causing water to flood the inner ear. The sudden influx of cold water against your balance mechanism may cause extreme dizziness (especially if only one eardrum breaks). Trying to equalize at this point could cause inner ear barotrauma due to the rupture of the round window, which sits between the middle and inner ears. This inner ear barotrauma may cause temporary or permanent hearing loss.


Common Injuries to the Ear:

Otitis Externa: Otherwise known as swimmers ear, otitis externa is an inflammation of the external ear due to infection. This is usually the cause of the ear remaining moist after immersion to water. The ear canal may become red, itchy or swollen. Prevention is the key!


Barotitis Media: Middle ear barotrauma is the most commonly reported injury by scuba divers. Symptoms, which can take a day or two to develop, include: a feeling of fullness, muffled hearing, and/or a feeling of fluid in the ears. It is suggested to stop diving (and other pressure changing activities—like flying) and see an otolaryngologist or an ear, nose and throat doctor.


Inner Ear Barotrauma: This inner ear damage can occur when divers attempt to forcefully equalize their ears. This unnecessary force causes the middle ear to overpressurize and can result in damage to the round and oval windows. These windows separate the middle from the inner ear. Many with inner ear barotrauma experience dizziness, vomiting, hearing loss and a ringing in the ears. See an audiologist or ear, nose and throat doctor if you’re experiencing these symptoms.


Tympanic Membrane Rupture: Another barotraumatic injury, this one causing a rupture of the eardrum (tympanic membrane). This can occur in as little as 7 feet of water. A TM rupture can result in pain and bleeding. See an ENT or medical practitioner for a consultation. Some ruptures can heal independent of intervention and some necessitate surgery to patch the hole.


External Ear Canal Superficial Vessel Rupture: Occurring more in divers who wear hoods, overpressure in the external ear canal can cause the blood vessels in the ear canal to rupture or burst. Individuals may notice a small amount of blood exit the ear.


If you ever experience ear pain, an injury, bleeding or hearing loss after scuba diving, see a medical professional (audiologist, otolaryngologist and/or an ENT) immediately. Stop diving until you get a medical consultation.


10 tips for Easy Equalizing:

  1. equalization-while-divingListen for the pop or click in both ears! This means both Eustachian tubes are open.
  2. Equalize early and often!
  3. Equalize at the surface or “pre-pressurize”. This will help you get past the critical first few feet of your descent, when you are busy clearing your mask or dumping your BC.
  4. Descend feet first. Air rises up the Eustachian tubes and mucus tends to drain downward. Many studies show that a Valsalva maneuver requires 50% MORE force when you’re in a head-down position than a head-up position.
  5. Look up. Extending your neck tends to open your Eustachian tubs.
  6. Use a descent line to control the speed of your descend.
  7. Stop if it hurts. Do not descend any more if you have not equalized your ears. This will help avoid barotrauma.
  8. Avoid milk and other dairy products before diving…it can increase your mucus production.
  9. Tobacco and alcohol can also affect your mucus membranes causing a blockage in your Eustachian tubes. So avoid it before diving!
  10. Keep your mask clear: water up your nose can irritate your mucus and cause more clogging blockage.


A picture of me scuba diving on Catalina Island, CA.

A note from the author:

“I received my scuba certification the summer of 2013 on Catalina Island. Upon training, I was asked to learn the anatomy of the ear and common issues that can go wrong due to poor or incorrect equalization. Since this was around the origin of my interest in audiology, I paid special attention to common ear injuries and issues that occur. I hope to be able to increase knowledge, awareness and concern of ear anatomy and injuries so individuals will not negatively impact their auditory health due to their hobbies and habits.”


Click here for a diver’s guide to ears: https://www.diversalertnetwork.org/medical/articles/download/DiversGuidetoEars.pdf



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