Diving Mask Squeeze

Etiology

Diving mask squeeze, a form of facial barotrauma, occurs when pressure inside the mask is not equalized during descent. As ambient pressure rises with depth, the air volume inside the mask decreases unless the diver actively exhales through the nose to balance the pressure. Without equalization, a relative vacuum forms inside the mask. The resulting negative pressure exerts force on the soft tissues of the face and eyes, leading to vascular rupture and tissue injury.

The condition is most commonly seen in beginner divers unaware of the need for equalization, or experienced divers using ill-fitting masks. Other contributing factors include rapid descent, facial hair compromising the mask seal, and nasal congestion preventing proper exhalation. Unlike other diving-related conditions, mask squeeze is not caused by gas toxicity or decompression, but by a mechanical failure to equalize pressure between the enclosed mask and the surrounding environment. Eye injury can also occur, including conjunctival hemorrhage and, rarely, orbital subperiosteal hematoma.[4][5]

Epidemiology

Scuba divers and freedivers, particularly those with limited experience, are at notable risk for developing mask squeeze, a form of barotrauma caused by improper equalization of pressure within the mask during descent. Even swimmers using goggles or masks that cover only the eyes, without including the nose, may be susceptible to similar injuries if they dive below the surface without appropriate precautions.

Accurate data on the incidence of mask squeeze remains limited, as many cases are mild and go unreported. At least 500 cases of diving-related barotrauma occur annually in the U.S., though the actual number is likely higher, given the tendency of divers to self-manage minor symptoms or fail to recognize the injury.

The Diver Alert Network (DAN) plays a crucial role in advancing diving safety by maintaining the largest global database of diving-related injuries, including barotraumatic conditions like mask squeeze. DAN operates a voluntary incident reporting system that allows divers and healthcare professionals to submit detailed accounts of diving injuries and near misses. In addition to data collection, DAN supports injury prevention through education, research, and emergency assistance services. By analyzing trends in reported cases, DAN enhances understanding of diving-related risks and informs safety recommendations, ultimately contributing to improved outcomes for divers worldwide.[6]

Pathophysiology

The pathophysiology of diving mask squeeze involves a pressure differential between the external environment and the internal mask space during descent. As a diver descends, ambient pressure increases according to Boyle’s Law, compressing any gas-filled space. Failure to equalize this pressure by exhaling through the nose into the mask creates a vacuum effect. The resulting negative pressure draws the mask inward, exerting force on the soft tissues of the periorbital and facial regions.

Mechanical stress can rupture superficial capillaries, causing subconjunctival hemorrhages, periorbital petechiae, and ecchymosis. Orbital emphysema or intraocular hemorrhage may occur in severe cases. The injury is confined to soft tissues and does not involve toxic, infectious, or systemic mechanisms. Although symptoms are often self-limiting, abrupt pressure-induced trauma may mimic more serious orbital or ocular injuries, necessitating careful clinical assessment to distinguish mask squeeze from other causes of facial or eye trauma.

Barotrauma can also elevate intraocular pressure (IOP), which may fluctuate during a dive depending on tank pressure, breathing cycles, and mask fit. Studies indicate that waterproof goggles without nose coverage produce a sustained rise in IOP, whereas those covering the nose do not.[7]

Histopathology

Histopathological examination of tissue affected by mask squeeze reveals nonspecific features of blunt soft tissue trauma. The conjunctiva and periorbital skin demonstrate disruption of capillary walls, interstitial hemorrhage, and edema. In cases of significant hemorrhage, histology shows extravasation of red blood cells in the subconjunctival and subcutaneous layers. Mild inflammatory infiltration with neutrophils and lymphocytes may occur due to tissue irritation, although necrosis is typically absent unless secondary infection is present. The skin may exhibit ecchymosis and dermal hemorrhage with preserved epidermal integrity. Chronic or repeated injuries can result in hemosiderin-laden macrophages in the dermis, reflecting prior bleeding episodes.

In severe trauma, orbital fat may show hemorrhage or fat necrosis, and vascular congestion may be prominent. The absence of arterial occlusion or thrombotic processes distinguishes mask squeeze from ischemic causes of ocular or facial injury. Histopathology further supports the diagnosis by confirming hemorrhagic features caused by mechanical pressure differentials rather than systemic or infectious etiologies. Biopsy is rarely required, as clinical presentation and history are usually sufficient, but histological findings are valuable for academic documentation or medicolegal purposes.

History and Physical

Patient history is vital for diagnosis. The clinician should inquire about recent scuba diving or freediving, including the diver’s experience level and the depth of the dive. Symptoms of mild mask squeeze include facial pain, redness, bruising, periorbital swelling, and subconjunctival hemorrhages. Rarely, more severe ocular injury may occur, with symptoms such as eye pain, proptosis, limited extraocular movements, diplopia, or other visual changes. Review of systems should also assess for signs of other diving-related injuries, including shortness of breath, cough, ear pain, epistaxis, or dizziness. The diver or companions may report suspected decompression illness.[8]

Physical examination should focus on affected areas, including the eyes, periorbital region, upper face, and forehead. Eye evaluation should include visual acuity and ocular range of motion. The presence of diplopia should likewise be determined. Suspicion of serious ocular injury warrants ophthalmologic consultation. Concern for decompression illness requires a more extensive evaluation, which is beyond the scope of this discussion.[9]

Evaluation

The history of present illness, review of systems, and physical examination are sufficient to establish the diagnosis for most cases. Computed tomography or magnetic resonance imaging of the orbits is indicated if any visual abnormalities are observed, including diplopia, proptosis, and restricted ocular movements.[10][11]

Treatment / Management

The vast majority of mask squeeze injuries require no treatment. Mild skin manifestations, including swelling, bruising, and petechiae, typically resolve within 1 to 2 weeks with supportive care. Mild ocular injuries, such as conjunctival hemorrhages, also resolve without intervention in a short time. Severe eye injuries, including subperiosteal orbital hematoma, require emergent evaluation by ophthalmology. Needle aspiration or orbitotomy with drainage may be necessary in cases involving optic nerve compression or increased IOP. Otherwise, conservative management with ophthalmology follow-up may suffice.[12][13](B3)

Unlike decompression-related injuries, mask squeeze results from a pressure gradient and not from microbubbles caused by decompression. Treatment does not include oxygen therapy or hyperbaric chamber use. Coexisting decompression injuries remain possible, so the examiner should assess for signs or symptoms suggesting such conditions.

Preventive education on proper mask equalization techniques during descent is crucial to avoid recurrence. Diving should be avoided until complete recovery is confirmed.

Differential Diagnosis

The diagnosis is usually established through history, physical examination, and imaging studies. The examiner should remain alert to the possibility of other diving-related injuries, such as decompression illness.

Diving mask squeeze is differentiated from several disorders with overlapping signs. Blunt orbital trauma presents with periorbital ecchymosis and swelling, but the bruising pattern is typically irregular and associated with a clear history of direct impact. This condition may also produce orbital fracture signs, such as bony step-offs or crepitus, which are absent in mask squeeze.[14]

Valsalva-related subconjunctival hemorrhage appears as a localized bright-red scleral patch without eyelid ecchymosis and is usually preceded by coughing, sneezing, or heavy lifting rather than underwater pressure changes. Preseptal cellulitis produces eyelid swelling, redness, and tenderness in the setting of infection, whereas orbital cellulitis demonstrates concomitant pain with eye movements, systemic features such as fever, and proptosis, none of which are typical for mask squeeze.

Basal skull fractures can cause bilateral periorbital ecchymosis (“raccoon eyes”), often without direct orbital injury, and are associated with significant head trauma or cerebrospinal fluid leakage.[15] Sinus barotrauma, another diving-related condition, presents with facial pain over the affected sinuses, nasal congestion, and, occasionally, epistaxis, but it lacks the subconjunctival hemorrhage and eyelid bruising characteristic of mask squeeze.

Prognosis

The prognosis for diving mask squeeze is generally excellent, with most cases resolving completely without long-term sequelae once the precipitating pressure imbalance is corrected. Mild cases typically recover within days to weeks with conservative management. Visual function is usually preserved, and cosmetic appearance returns to normal, even in instances of more extensive subconjunctival hemorrhage or periorbital ecchymosis. Severe ocular involvement is rare, and outcomes remain excellent in areas with ready access to ophthalmic care.

Complications

Complications from diving mask squeeze are uncommon, typically arising only when the condition is not promptly recognized or appropriately managed. More serious ocular injury may occur in rare cases, particularly if significant blunt trauma accompanies the barotrauma. Concurrent decompression illness can further complicate the clinical picture. Clinicians should remain vigilant for coexisting diving-related conditions to ensure timely diagnosis and management.