to successful ear equalization is to keep the pressure difference between the water and the middle ear to a minimum. This means that you must equalize early and often, starting at just beneath the surface. If the pressure difference between the inside of your ear and the water becomes marked, the pressure will hold the Eustachian tube closed (figure 4-23). Once this happens, it is unlikely that you can do anything at that depth that will open the tubes. Your better choice is to ascend a few feet and reduce the pressure difference until the tubes will open, and then attempt to equalize again. In some cases, divers will need to return to the surface and start their descent from the beginning. Never try to equalize pressure in a squeezed ear by performing forceful blowing. Blowing hard against a closed nose and mouth will not open your Eustachian tubes if they are held shut by pressure. When the tubes are closed by pressure, they can actually seal tighter when you blow harder. This increases the pressure on your inner ear, which can permanently damage your hearing. Never try to force the Eustachian tubes open by blowing hard. It is much better to equalize your ears continually during descent than it is to repeatedly descend too far, have trouble equalizing, and have to rise a few feet in the water. Most divers have no problem if they begin equalizing just beneath the surface and then equalize continually on descent. Descending feet first also makes equalizing much easier for most people. Always remember to equalize early and often! Some other techniques you can use to equalize Chapter 4- Diving Science your ears while closing your nose and mouth include wiggling the jaw, tilting the head from side to side, and putting your tongue to the roof of your mouth and compress the trapped air with your tounge. Any of these methods are acceptable and should help to keep the pressure in your ears equalized. If an eardrum ruptures because you carelessly ignored the pain that signals an ear squeeze, water will enter your middle ear. Even if you are diving in the tropics, this water will be colder than the temperature inside your ear. When the water enters your middle ear, it shocks your balance mechanism and can cause vertigo (dizziness). If this occurs, hold on to any stable object that is close by, or hug yourself to provide stability. You must allow time for the water that has entered your ear to warm to body temperature. This will happen quickly and your sense of orientation and balance will return. If you do suffer rupture of an eardrum, you must surface and seek medical attention immediately to minimize the possibility of infection. You will not be able to dive again until your eardrum has healed and your doctor permits you to get back in the water. Remember that this injury normally only occurs to divers who disregard pressure in the ears. If you have a head cold, you must not attempt to dive and equalize by any method. Equalizing when you have a cold can force mucous and bacteria into the middle ear space, which could lead to infection. Using decongestant drugs is not the answer. Decongestant drugs might be only partially effective, or might lose their effect when you are under water, with a variety of adverse consequences. Never use earplugs for skin or scuba diving. Earplugs trap air between themselves and the eardrum. Because there is no way to equalize this air space, the earplugs can be driven into the outer ear canal by the surrounding pressure. This is a painful and serious injury. Middle Ear Blocks A reverse block can occur, affecting your middle ear, if your Eustachian tube becomes blocked while you are at depth. If you begin to ascend and your ear hurts and feels “full,” stop your ascent and descend until the Diving Science 109 FIGURE 4-23. IF YOU DESCEND TOO FAR WITHOUT EQUALIZING, YOU MIGHT HAVE TIGHTLY CLOSED EUSTACHIAN TUBES.
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