Blunt Eye Trauma

Etiology

Blunt eye trauma can manifest as open globe and close globe injury. The closed globe injuries are broadly classified as contusion and lamellar lacerations. Open globe injuries can be divided into laceration and globe rupture. The laceration is secondary to penetrating injury, perforation injury, or injury due to an impacted intraocular foreign body (IOFB). The mechanism of blunt eye trauma can be due to coup, countercoup, and anteroposterior compression or horizontal expansion of the tissue. The mode of injury can be a direct blow to the eyeball or accidental blunt trauma.[6]

Closed globe injuries are often seen in pediatric children while playing with friends and at home. The most common pediatric eye injuries are sports-related trauma, wooden stick injury, and thermal burns due to firecrackers. The other common modes of injury can be assault, workplace trauma, road traffic accidents, self-fall, and nonaccidental injuries.[7] These injuries are more common in adults. Closed globe injuries can also be accidental and are broadly listed as occupational and occupational. The occupational injuries can be due to high-risk occupations like the manufacturing industry, plumbing, mining, and agriculture. Nonoccupational can be sports trauma and domestic violence.[8]

Globe rupture occurs when there is a defect in the cornea, sclera, or both structures. Global rupture often occurs after direct penetrating trauma; however, if sufficient blunt force is applied to the eye, the intraocular pressure can increase enough to rupture the sclera. The high-velocity impact or sharp cutting objects may result in perforating or penetrating open globe injuries.[8] Injuries from sharp toys, knives, scissors, screwdrivers, spectacles, household chickens, pets, and other animals like cranes and swans are prevalent in children. The most common is scissor injury. In adults, the most common causes of blunt eye trauma are workplace injury, stick injury, chemical fall, iron rod, iron nail, quarrel, assault, wood, brick, cement, and battery injury.[9] In elderly age, the most common injury mode is falling from bed, in the bathroom, falling from vehicles resulting in self-inflicted trauma, and falling on the ground. Females are more commonly affected in the elderly age group.

A retrobulbar hematoma is frequently associated with orbital trauma and associated orbital floor fractures. This trauma may also occur iatrogenically during sinus surgery, ocular surgery, or other eye procedures. In the setting of anticoagulation, this may occur in rare scenarios with increases in Valsalva (e.g., from vomiting, straining, or coughing).[10][11]

Epidemiology

The incidence of globe injuries is quoted as 3.5 eye injuries per 100,000 persons, with males constituting about 80% of open globe injuries. Injuries in the pediatric population are more often with sharp objects directly penetrating the globe (e.g., writing utensils, scissors, or knives). The cause is often blunt trauma (e.g., motor vehicle collisions, altercations, or work-related injuries involving hammering). In the elderly, globe rupture is most often a result of falling.[12][13] The incidence of retrobulbar hematoma is rare; it has been recorded as less than 1%. However, there is a strong association between this diagnosis and subsequent blindness.[14] Open globe injuries are more common in males, usually in the age group of 30 to 40 years. After penetrating and perforating, injuries retained intraocular foreign body (IOFB) can be seen in 40% of cases and may be seen while perforation work such as hammering, grinding, and drilling.[15] 

A recent analysis from North India gave insights into nonoccupational and occupational. As per the study, nonoccupational trauma constituted 82.3%. There were 23.9% cases of sports-related trauma and 23.6% cases of road traffic accidents. Approximately 89.3% of cases constituted mechanical injuries. The various modes of trauma were wood injury 24.9%, and metallic object 20.9% for open globe injury. The incidence of blunt trauma was three times less than that of sharp objects (56%).[16]]

Landen et al., in their analysis, reported an annual incidence of 3.5 per 100000 cases of perforating injuries in the USA. Another study from Australia reported 2.4 and 7.9% per 1000 cases of nonindigenous and indigenous adults with monocular blindness due to blunt trauma.[17] As per another analysis by Negrel et al., three quarter million patients undergo hospitalization with ocular injuries globally.[18] Ocular trauma is approximately 7% of all body trauma and 10 to 15% of all ophthalmic pathologies. Globally1.6 million people are blind due to ocular trauma, 2.3 million are bilaterally blind, and 1.9 million are monocularly blind. Approximately 90% of all ocular injuries can be prevented.[19]

Pathophysiology

Globe rupture occurs when there is a defect in the cornea, sclera, or both structures. Global rupture often occurs after direct penetrating trauma; however, if sufficient blunt force is applied to the eye, the intraocular pressure can increase enough to rupture the sclera. The rupture site is most commonly near the globe's equator posterior to the insertion of the rectus muscles, which is where the sclera is weakest and thinnest.[20] A retrobulbar hematoma occurs when blood is accumulated in the retrobulbar space. As blood collects behind the eye, there is increased intraocular pressure, which can subsequently cause stretching of the optic nerve. Within several hours, decreased ocular perfusion can lead to permanent blindness.[21]

Injury Division

• Direct or Coup - Direct blow to the eye. e.g., Corneal abrasion
• Countercoup - Due to pressure waves transmitted at the posterior pole. e.g., commotio retinae
• Anteroposterior Compression and Horizontal Expansion - Pressure waves in the anteroposterior and horizontal axes. e.g., globe rupture[22]

Blunt Trauma Division

• Direct -injury to the eye by hand, fist, ball, or blunt instruments like a stick, stone, and iron rod
• Accidental- accidental trauma like a fall from a bike, self-fall, stone injury, cracker injury, etc

Stages of the Mechanism of Blunt Trauma

• Direct impact
• Compression wave force
• Reflected compression wave
• Rebound compression wave[23]

History and Physical

High suspicion for globe injury exists in any patient reporting direct eye trauma, continuing eye pain, and vision deficit. The mechanism of the injury should be elicited and the time it occurred. It is also essential to inquire about any anticoagulant use. In globe rupture, physical examination findings may reveal decreased vision or frank vision loss, the irregular contour of the globe, teardrop pupil, hyphema, or a shallow anterior chamber on the slit-lamp exam. The Seidel sign is positive in globe rupture, indicating the flow of aqueous humor from the injury site in the fluorescein-stained eye. However, if the globe rupture is apparent, Seidel's test should be avoided. The clinical presentation of retrobulbar hematoma is classical with proptosis and severe eye pain. As in globe rupture, vision loss may be reported.[24]

There may be associated periorbital swelling, ecchymosis, or subconjunctival hemorrhage in either of these entities, depending on the mechanism of the injury. Typical symptoms of globe rupture include eye deformity, eye pain, and vision loss, though the deformation may not be readily apparent on the exam, depending on the clinical suggestion. Similarly, a retrobulbar hematoma may present with eye pain and vision loss, but proptosis helps clinch this diagnosis. Both are vision-threatening diagnoses and require emergency ophthalmologic consultation for definitive measures.[25][26][27]

Manifestations

Anterior Segment Manifestations

Conjunctiva

• Subconjunctival hemorrhage
• Conjunctival congestion
• Foreign body of conjunctiva
• Conjunctival tear[28] 

Cornea

• Epithelial damage - There can be abrasion, punctate epithelial erosions, epithelial defect, foreign body due to breach in the epithelium and revealed brilliantly on fluorescein staining. If the damage involves the pupillary axis, the vision is grossly impaired.[29]
• Corneal edema - There can be corneal edema due to endothelial injury or extensive damage due to abrasion. Corneal edema usually is associated with stromal edema, and Descemet membrane (D.M.) folds.[30]
• Descemet membrane tear - D.M. tears are vertical tears noticed after birth trauma. Recurrent corneal erosions.[31]
• Recurrent corneal erosions (recurrent keractalgia) - Usually result from fingernail injury. The patients will present as pain, redness, watering, and photophobia due to loose attachment of epithelium to the underlying Bowman's membrane.[32]
• Corneal tear (Partial or lamellar or full-thickness tear) - There can be self-sealed tears or total thickness tears best detected with Seidel's test.[33]
• Blood staining of endothelium - This may be secondary to hyphema or raised IOP and may take as long as two years to clear. The blood staining of endothelium clears from periphery to center.[34]
• Corneal scar - May be seen after a long duration post-trauma, usually after 2-3 months.[35]
• Corneal infiltrate - Blunt trauma can also result in a corneal ulcer.[36]

Sclera

Can have a partial thickness or full thickness tear with or without vitreous prolapse. There can also be occult posterior tears. Sometimes the foreign body can be lodged in the sclera. The sclera is thinnest at the equator; hence occult posterior equatorial injuries are common. The direction of trauma also determines the site of the tear. e.g., the sclera usually gives way at the site of old manual small incision cataracts surgery incision in case of inferior blunt trauma.[37]

Anterior Chamber Hyphema

• Anterior chamber hyphema - can also result from a blunt trauma from the iris root or ciliary body. The blood settles down at the bottom of the chamber with a particular fluid level. Hyphema can result in raised IOP and manifest as optic neuropathy and corneal endothelial staining.[38]

Hyphema Grading

• Anterior chamber exudates and fibrinous membrane - can also be seen due to traumatic uveitis. Traumatic glaucoma or angle recession glaucoma can be detected on gonioscopy post blunt trauma. Angle recession is the separation of longitudinal muscle fibers from circular muscle fibers of the ciliary body, resulting in widened ciliary body band and deep anterior chamber.[39]

Iris

• Iridodialysis - It is the separation of the iris root from the ciliary body. It is described as D-shaped with a biconvex area adjacent to the limbus best visible on retro illumination. The upper lid masks superior iridodialysis, but iridodialysis in other quadrants caused glare, photophobia, and monocular diplopia. Very rarely, blunt trauma can result in 360-degree iridodialysis with extrusion of the iris through cataract surgery tunnel resulting in aniridia.[40]
• Iris stromal tears - Tears in the iris stromal tissue

Pupil

• Traumatic mydriasis (iridoplegia) - Iridoplegia is due to spasms of the sphincter muscle[41]
• Traumatic miosis - It occurs due to the irritation of ciliary muscles and loss of accommodation[42]
• Pupillary margin rupture - multiple sphincter tears at the pupillary margin

Ciliary Body

• Ciliary body detachment - result in ciliary body shutdown and hypotony.[43]

Lens

• Cataract - Traumatic cataracts can result from blunt trauma due to direct damage to the lens and ruptures in the lens capsule leading to an aqueous humour inflow, lenticular fiber hydration, and opacification of lens fibers.[44]
• Vossius ring - Ring-shaped impression of the pupillary margin over the anterior lens capsule due to blunt trauma. The ring is usually smaller than the pupillary diameter.[45]
• Rosette cataract - Blunt trauma can manifest as opacification of posterior subcapsular cortex and sutures, resulting in a flower-shaped cataract.[46]
• Subluxation - Subluxation can result from zonular dialysis or damage to suspensory ligaments. The lens may tilt towards the area of intact zonules. The anterior chamber becomes deep, and the lens may tilt or rotate posteriorly. The lenticular edges and zonules can be seen during dilatation, and there may be iridodonesis and phacodonesis with blinking and ocular movements. If there is gross subluxation, it may result in diplopia and astigmatism from the aphakic portion of the lens.[47]
• Dislocation - When the zonular fibers are damaged completely, they may dislodge the lens in the anterior chamber or the vitreous cavity.[48]

Globe Rupture

Globe rupture can also result after severe blunt trauma. If the visual acuity at presentation is light perception, the prognosis is usually poor. Globe rupture usually occurs adjacent to the angle structures, with prolapse of iris, lens, ciliary body, and vitreous. Anterior globe rupture can be hidden by subconjunctival hemorrhage, and rupture at the site of the old surgical wound like cataract and keratoplasty may result from severe blunt trauma. An occult posterior rupture can be present when the anterior chamber depth is variable. The rupture can be the site of recti muscle insertion, where the scleral is the thinnest.[49]

Posterior Segment Manifestations

Optic Nerve

• Optic nerve avulsion - It is a rare manifestation when a foreign body or object gets impacted between the globe and orbital wall, thus displacing the eye. The mechanism implicated is the rotation or anterior movement of the globe. It can occur as isolated or in association with other orbital trauma. Fundoscopy shows retraction of the optic nerve head from the dural sheath. The visual prognosis is poor in most cases, and there is no treatment.[50]
• Traumatic optic neuropathy - Traumatic optic neuropathy can also result from blunt head or orbital trauma. The patient usually presents with sudden vision loss, and there is RAPD with color vision defect.[51]

Vitreous

• Vitreous hemorrhage - It can be seen in association with posterior vitreous detachment. Pigmentary cells floating in the vitreous, also called tobacco dust, can be noticed. The tobacco dusting may or may not be associated with a retinal tear.[52]]
• Vitreous detachment - It can be anterior or posterior[53]
• Vitreous opacities - Liquefaction of vitreous can occur, and clouds of opacities can be present.[54]
• Vitreous prolapse - Can occur in an anterior chamber associated with subluxated or dislocated cataracts.[55]

Choroid

• Choroidal rupture - Usually temporal to the optic disc and its circular shape. It can be associated with pigmentation at the margins.[56]
• Choroidal hemorrhage - Can be seen under the retina, or the blood may enter the vitreous in case of retinal tear.[57]
• Choroidal detachment - Kissing choroidals are also observable in cases of blunt trauma.[57]
• Traumatic choroiditis - Patches of depigmentation and discoloration can be seen.[58]

Retina

• Berlin's Edema (Commotio Retinae) - It usually presents as a cherry spot at the fovea and results in milky white cloudiness at the posterior pole. Usually, berlin's edema resolves on its own and, in some cases, may manifest as pigmentary changes at the fovea.[59]
• Retinal tear - It occurs in eyes predisposed to retinal tears like myopia, white without pressure, or senile degeneration after blunt trauma.[60]
• Retinal detachment - It may manifest after blunt trauma in the eyes with retinal tears or vitreoretinal traction. Approximately 10% of retinal detachments are secondary to blunt ocular trauma and are more common in young boys. There can be retinal dialysis, giant retinal tear, or equatorial breaks.[60]
• Traumatic Proliferative Retinopathy - It occurs in cases with vitreous hemorrhage.[61]
• Retinal hemorrhage - There can be flame-shaped or boat-shaped. Flame-shaped hemorrhage occurs in cases with blunt trauma.[62]

 Macula

• Macular edema - due to concussion injury after blunt trauma[63]
• Pigmentary degeneration - Pigmentary degeneration is usually observed in long-standing cases after blunt eye trauma[64]
• Macular hole - Traumatic macular can be seen after blunt eye trauma[65]
• Macular cyst - Traumatic macular cyst can be also be observed after blunt trauma[66]
• Macular scar - Macular scar can also be seen after blunt eye trauma[67]

Evaluation

Visual Acuity

Visual acuity should be evaluated in each eye separately, if possible, taking care not to manipulate any possible intrinsic globe injury. Pupillary defects should also be noted.[68]

Intraocular Pressure

Intraocular pressure assessment by noncontact tonometry or applanation tonometry is essential in cases of blunt trauma, as secondary glaucoma can result in acute vision loss. Traumatic secondary glaucoma can occur due to blockage, damage, or collapse of the trabecular meshwork, and angle-closure and hypotony can be secondary ciliary body detachment.[69]

Gonioscopy

Gonioscopy is helpful to rule out a foreign body, blood in Schlemm's canal, blood in angles, pigment dispersion, and angle recession. Gonioscopy should be performed under topical anesthesia with 0.5% proparacaine and when the eye is not inflamed. Gonioscopy can be deferred or delayed in case of pain.[69]

Fluorescein Staining

This investigation is essential to locate the epithelial defect, look for abrasions, erosions, and seidel's test.[70]

Seidel's Test

The cornea is stained with fluorescein under topical anesthesia, and the tear site is observed for spontaneous aqueous leak under a cobalt blue filter.[71]

Forced Seidel's Test

The cornea is stained with fluorescein stain under topical anesthesia, and the tear site is observed for an aqueous leak on pressure on the globe under a cobalt blue filter.[71]

Imaging

X-Ray

A plain X-ray of the skull and orbit is helpful to locate any intraocular foreign body. A metallic foreign can show positional changes due to up and down movement.[72]

B Scan Ultrasonography

This is an essential tool to locate retinal IOFB rule out retinal detachment, globe rupture, vitreous hemorrhage, choroidal detachment, and suprachoroidal hemorrhage. The examining ophthalmologist has to be careful not to exert excess pressure on the globe in case of open globe injuries to prevent extrusion of intraocular contents.[72]

Computed Tomography

Computed tomography (C.T.) imaging can rule out additional maxillofacial injuries while confirming the diagnosis. In addition to globe deformity and retrobulbar hematoma, C.T. imaging can evaluate foreign bodies, scleral disruption, and even vitreous hemorrhage. It is superior to X-ray in locating and detecting IOFBs.[72]

Magnetic Resonance Imaging

Magnetic Resonance Imaging (MRI) is superior in detecting and locating occult posterior rupture and soft tissue trauma. MRI is not indicated in cases of metallic foreign bodies.[72]

Electrodiagnostic Tests

In cases of doubtful visual acuity, electroretinogram (ERG), electrooculography (EOG), visual evoked potential (VEP) are helpful to assess the integrity of the optic nerve and retina.[72]

Optical Coherence Tomography

This investigation is useful to look at the morphology and anatomy of the macula and rule out the macular hole, macular edema, scar, and disruption of IS-OS junction.[72]

A thorough evaluation of any concomitant intracranial and facial bony injury should be pursued. A high number of globe ruptures and retrobulbar hematomas are associated with fractures, particularly the orbital floor. Extraocular motility testing may be decreased in the affected eye because of entrapment, intrinsic globe deformity, or retrobulbar hematoma. Laboratory evaluation should be pursued as the clinical situation dictates in the setting of trauma or anticoagulant use.  

Treatment / Management

For globe rupture, emergency department treatment includes supportive measures to prevent worsening of the injury or extrusion of intraocular contents. Hence, antiemetics should be provided to prevent Valsalva from vomiting, leading to increased intraocular pressures and subsequent loss of aqueous fluid. Analgesia should be provided as needed. A rigid eye shield should be placed, and additional manipulation of the eye should be avoided. The patient should be placed in a semi-recumbent position.[73][74][75]

Similarly, in retrobulbar hematoma, analgesia and antiemetic should be provided. Definitive therapy, however, is immediate decompression with a lateral canthotomy and inferior cantholysis. This can be performed by the emergency medicine provider or the ophthalmologist if there are no delays in the consultant performing this procedure. Vision prognosis is time-sensitive in this setting, with poorer outcomes seen in delays of greater than 4 hours from the time of symptoms. Prophylactic antibiotics can be used to prevent secondary endophthalmitis.[14]

In the setting of globe injury or retrobulbar hematoma, emergent consultation with ophthalmology is warranted. Definitive management in these diagnoses is surgical repair by the appropriate ophthalmologic specialist.

Management of Various Manifestations of Blunt Eye Trauma

Differential Diagnosis

The differential diagnosis of blunt trauma to the eye includes

• Globe rupture
• Retrobulbar hematoma
• Traumatic glaucoma
• Hyphema
• Orbital blowout fracture with entrapment
• Foreign body
• Scleral disruption
• Vitreous hemorrhage

Prognosis

The prognosis of blunt eye trauma depends heavily on the sequela of the trauma. One study showed that ocular trauma, in general, resulted in monocular blindness in one-quarter of patients.[76] In kids, research has shown that visual acuity is generally better in blunt ocular injury compared to penetrating ocular injury, although rates of glaucoma may be higher in blunt ocular trauma.[77] However, if the eye is ruptured, blunt ocular trauma may lead to the worst visual prognosis since that most likely means the trauma occurred at a high velocity. Other factors that may lead to a worse visual prognosis include a relative afferent pupillary defect, absence of a red reflex, initial visual acuity worse than 20/200, and an eyelid laceration.[78] In another study, in patients with commotio retinae or sclopetaria retinae from blunt ocular trauma, a quarter of patients had visual acuity worse than 20/30 in the eye that had the trauma.[79] Visual acuity is worse after blunt ocular trauma if there is a hyphema, retinal detachment, and/or vitreous hemorrhage.[37] Traumatic optic neuropathy also portends a poor visual outcome.[80]

The extent of the initial injury and the injury mechanism often predict whether poor outcomes might be expected. To give the best prognosis of an individual's visual prognosis, the Ocular Trauma Score is a verified method to predict the functional outcome of an eye after trauma.[81]

Complications

Depending on the type and extent of the trauma to the eye, complications may vary based on the location and depth of injury.

• Conjunctival Tear
• Corneal Tear
• Corneal infiltrates
• Corneal scarring  
• Hyphema
• Hypopyon
• Anterior chamber exudates
• Fibrinous membrane
• Iridodialysis
• Iris prolapse
• Traumatic Mydriasis
• Iridoplegia
• Angle-closure glaucoma
• Post-traumatic glaucoma
• Subluxated lens
• Dislocated lens
• Subluxated IOL
• Dislocated IOL
• Posterior capsular rupture
• Zonular dialysis
• Cataracts
• Retinal Tear
• Retinal detachment
• Choroidal detachment
• Choroidal rupture
• Traumatic optic neuropathy
• Optic nerve avulsion
• Endophthalmitis
• Panophthalmitis

Varying degrees of vision loss may also occur. Enucleation may be required in severe trauma not amenable to ophthalmologic surgical repair.