An orbital floor fracture is a common type of facial trauma, often resulting from a blunt force impact to the eye. This injury involves a break in the thin bone at the bottom of the orbit. This type of fracture requires prompt evaluation by medical professionals, as it can compromise vision, alter the appearance of the eye, and affect normal eye movement.
The Anatomy of the Eye Socket
The orbit is the bony socket that houses the eyeball, muscles, nerves, blood vessels, and fat, providing protection from external forces. This bony structure is formed by seven different bones, with the orbital floor being primarily composed of the maxillary bone, along with smaller contributions from the zygomatic and palatine bones. The floor is the shortest wall of the orbit, notably thin above the maxillary sinus.
This structural weakness explains the mechanism of what is commonly known as a “blowout fracture.” When a blunt object, such as a fist or a ball, strikes the eye, the force is transmitted to the globe, rapidly increasing the internal pressure within the orbit. This pressure surge pushes the orbital contents downward and outward, causing the floor to fracture and buckle into the maxillary sinus below. Orbital tissue, including fat and sometimes muscle, can then prolapse into the fracture site.
Recognizable Signs and Symptoms
One of the most frequent clinical indications of an orbital floor fracture is diplopia, or double vision. This occurs when the inferior rectus muscle, which controls downward eye movement, or the surrounding soft tissue becomes entrapped within the fractured bone fragments. The muscle is physically restricted from moving, leading to a noticeable limitation in the eye’s ability to gaze upward. The presence of diplopia with restricted eye movement requires immediate medical evaluation.
Another sign is enophthalmos, the sunken appearance of the eye. This happens because the fracture increases the overall volume of the orbital cavity, allowing the eyeball to recede slightly into the socket. Enophthalmos greater than two millimeters is a significant finding, often causing noticeable facial asymmetry.
Patients often report numbness or a tingling sensation in the cheek, upper lip, and upper gums. This sensory disturbance is due to trauma to the infraorbital nerve, a branch of the trigeminal nerve that runs along a groove and canal in the orbital floor. The nerve can be compressed or impinged by displaced bone fragments, leading to a temporary or persistent loss of feeling in the areas it supplies.
Diagnosis and Management Strategies
The first step in confirming an orbital floor fracture is a thorough physical and ophthalmological examination, focusing on visual acuity and the range of eye motion. The definitive diagnostic tool is a high-resolution computed tomography (CT) scan. CT scans are superior to traditional X-rays for this injury because they provide detailed, three-dimensional visualization of the bony structures and soft tissues, allowing clinicians to assess the size of the fracture and whether any muscle or fat is trapped.
Management strategies are divided into non-surgical observation and surgical repair, depending on the severity of the injury and the resulting symptoms. Non-surgical management is appropriate for small, non-displaced fractures without significant eye muscle entrapment or vision compromise. This approach involves close observation for up to two weeks, cold compresses to reduce swelling, and instructions to avoid activities like nose-blowing, which could force air into the orbit. Antibiotics may be prescribed to prevent infection of the nearby sinuses.
Surgical intervention is indicated if there is persistent, symptomatic diplopia due to muscle entrapment, a fracture involving more than 50% of the orbital floor, or enophthalmos greater than two millimeters. The surgery aims to free any trapped soft tissues, particularly the inferior rectus muscle, and reconstruct the orbital floor. Surgeons use materials like titanium mesh or specialized implants to bridge the defect and restore the original orbital volume. This reconstruction prevents the long-term complication of a sunken eye and restores normal eye movement.
Post-Treatment Recovery and Outlook
The recovery timeline for an orbital floor fracture varies based on the fracture’s severity and whether surgery was required. Non-surgical cases show improvement in swelling and symptoms within the first few weeks, with bone healing taking four to eight weeks. Patients undergoing surgical repair need a few days to a week before returning to light activities, but must avoid strenuous activity or heavy lifting for at least three weeks to prevent re-injury.
Full healing and symptom resolution can take two to three months, or longer for complex cases. Follow-up appointments monitor visual function and muscle movement, sometimes involving specialized eye exercises or physical therapy to regain full range of motion. A potential long-term complication is persistent minor double vision, especially in extreme gazes, which may necessitate corrective glasses or additional eye muscle surgery. Residual numbness from nerve damage often improves gradually over many months.