A recent forensic case study has drawn attention to how a diver's failure to equalise mask pressure during descent can lead to facial injuries that resemble blunt trauma. Known as "mask squeeze" or facial barotrauma, this condition can cause dramatic bruising around the eyes and other soft tissue injuries when negative pressure develops inside a dive mask.

Failure to equalise

In this incident, the diver lost consciousness underwater and was unable to equalise pressure inside the mask. As the descent continued, the imbalance created a vacuum that pulled facial tissues into the mask cavity, resulting in periorbital bruising—commonly known as "raccoon eyes"—and subconjunctival haemorrhages.

Video footage confirmed the diver was on a solo dive and that the incident was accidental. The diver ultimately drowned, and the pressure injury was found to have occurred prior to death.

What mask squeeze does

Mask squeeze occurs when pressure outside the mask increases faster than the diver equalises it by exhaling through the nose. The resulting pressure differential can rupture blood vessels in the eyes, cheeks, and forehead. In severe cases, the facial soft tissue damage can be extensive and visually misleading.

While it is quite unlikely that a conscious diver would fail to notice and respond to the growing discomfort or pain caused by mask squeeze, this case illustrates that under certain conditions—such as unconsciousness—it can result in significant tissue damage around the eyes.

In severe cases, the facial soft tissue damage can be extensive.

Common, but underappreciated

While ear and sinus barotrauma are better known, facial barotrauma is a documented risk in diving. Most incidents are mild and resolve on their own, but extreme cases like this one illustrate the potential severity. Divers should be aware of the need to routinely equalise mask pressure during descent.