Manufacturers of vented diving earplugs (e.g., Doc's Proplugs) assert that these devices ease equalization and keep water out of the ears. The latter feature is said to reduce the frequency of otitis externa — more commonly referred to as swimmer’s ear, which is an infection of the external ear canal — and exostosis, or surfer’s ear, which is an abnormal bone growth within the ear canal.
The claim of easing equalization is difficult to support as there is no reasonable mechanism of which I am aware to explain how this might occur. Doc's Proplugs' web site states, "Due to surface tension, the vented plug also reduces abrupt pressure changes from reaching the sensitive eardrum which contributes to easier equalization,” a line of reasoning that I am unable to follow.
To the extent that a vented diving earplug lessened the flow of water into the external auditory canal, the expectation is that outer ear infections would be less likely. Decreased water flow also would be expected to reduce temperature-related abnormalities, such as caloric vertigo and surfer's ear.
Although anecdotes abound, only the most minimal acceptable medical research has been conducted on these plugs to date, and all that has been demonstrated is reduced bony growth in the external ear canal caused by exposure to cold, wet and windy conditions during various watersports.
Provided that the vent in the plug remains unobstructed, these devices appear to pose little danger to the ear. However, if a vent should become clogged, especially upon descent, equalisation could become impeded and the eardrum damaged.
As for using such plugs to protect a ruptured eardrum, remember that these devices still do admit a small amount of water. Plus, the diver runs the risk of losing the plug altogether, thus allowing water to freely enter the middle ear space and cause pain, disorienting vertigo, and possible middle-ear infection.
The bottom line is if you're experiencing external ear infections or worried about surfer's ear, properly used vented plugs may be worth the small investment. However, divers with a history of middle-ear congestion or infection are unlikely to benefit from these plugs, and they should refrain from diving until seen by an ear, nose and throat specialist. For those with continuing difficulty in equalising, experiment with various clearing techniques before trying vented ear plugs.
Having trouble equalising your ears? Learn some great tips and techniques for easy equalising in our Healthy Diver: Ear Clearing 101 article.
DocVikingo has been scuba certified for more than 35 years and has dived all over the world. He is a practising doctor in the Baltimore/Washington, D.C., area and has held faculty positions at several major hospitals, including Johns Hopkins. With an interest in diving medicine, he serves as administrator at Scuba Clinic Online.