A corneal laceration is a partial- or full-thickness injury to the cornea that can occur from trauma to the eye. A partial-thickness injury does not violate the globe of the eye (abrasion). A full-thickness injury penetrates through all the layers of the cornea, resulting in ruptured globe. These lacerations vary in size, shape, and severity. This article will focus on full-thickness injury.
While history may point to the etiology of the laceration, sometimes the patient may not remember a discrete inciting event. Patients may not recall things such as s mall foreign bodies , digital trauma, or other subtle sources of damage. The physician must be meticulous in examining the cornea and periorbital structures if there is suspicion of a corneal laceration. Typically, patients who present with this type of injury experience intense pain, lacrimation, photophobia, and demonstrate conjunctival injection and visual disturbance.
When evaluating eye trauma with evidence of corneal injury, it is important to assess for full-thickness laceration and the resulting ruptured globe. With a ruptured globe, aqueous humor escapes the anterior chamber, which can result in a flat-appearing cornea, air bubbles under the cornea, or an asymmetric pupil secondary to the iris protruding through the corneal defect.
For more information, see Medscape's Cornea and External Disease Resource Center and Medscape's Ophthalmology Specialty page.
United States
The United States Eye Injury Registry (USEIR) is a terrific resource for nationwide eye trauma epidemiology, prevention techniques, and educational resources.
Approximately 2% of all emergency department visits are due to eye injuries affecting an estimated 24 million Americans.[1, 2] Additionally, eye injury is responsible for 1.6 million cases of blindness worldwide.[3] Major risk factors for eye injury include age, gender, and socioeconomic status. [3]
Penetrating eye injury can occur in individuals of any age, but data from USEIR demonstrate that the mean age of ocular injury is 29 years and the median age is 26 years, with nearly 60% being younger than 30 years. [4]
The American Academy of Ophthalmology also has statistics that suggest similar trends to the USEIR data.
The Centers for Disease Control and Prevention/National Institute of Occupational Safety and Health features information pertaining to work-related eye injuries. With occupational exposures, more than 90% of eye injuries are preventable with the use of protective eyewear.[1]
International
International epidemiology of penetrating eye injury reveals similar demographics showing most injuries occur in male, and younger age groups, and the most common location is at home.[5] In children, a significant amount of the inciting events occurred while they were unsupervised. Local activities such as preparations of explosives, bonfires, and shots of blowguns predispose to corneal injury (eg, fireworks injuries).
Mortality from corneal lacerations is rare, but morbidity can be significant. Corneal lacerations or subsequent secondary infection (endophthalmitis) can result in complete or partial loss of vision, loss of the eye, or systemic infection. Other complications include corneal scarring and cataract formation, and secondary glaucoma can also lead to vision loss.[6] Early diagnosis and treatment can improve significantly improve outcomes.
Males are about 1.7 times more likely than females to have a penetrating ocular injury.[1]
The majority of patients presenting to the Emergency Department for penetrating eye injury are represented in the less than 40 years age group, making up 77% of the cases.[7] The mean age for eye injury is 29 years. There are also age variations based on the mechanism of injury, consistent with age-specific activities and risk factors. Ocular trauma from reactional sharp injury predominantly occurs in patients less than 20 years.[7] About 75% of patients that sustained an eye injury due to a fall were aged 50 years and older.[7]
The human cornea comprises the following 6 layers: epithelium, Bowman's layer, stroma, Dua's layer, Descemet's membrane, and endothelium. An injury and defect to the epithelium leaves the eye susceptible to infection. Injury involving the Bowman's and deeper layers are likely to result in corneal scarring and consequently limit visual clarity. The non-regenerating cells of the endothelium house the sodium-potassium channels that keeps the cornea dry and clear. Violation of the endothelium results in a cloudy edematous cornea.
The prognosis after corneal laceration depends on the extent of the injury. Factors to consider include but are not limited to location, length, depth, and complexity of laceration, as well as the degree of scarring. Extensive corneal scarring may affect vision, requiring corneal transplant in the future. Laceration involving deeper globe structures such as the lens, retina, and uveal tissue may have a guarded prognosis.
Individuals should seek immediate medical attention if there is suspicion of injury to the eye or if they experience eye pain, redness, excessive tearing, vision loss or change.
A physician's evaluation will be centered on visual inspection of the effected eye(s) and may include visual acuity testing, fluroscein staining exam, ocular pressure measurement, removal of any visible foreign bodies, CT imaging, and consultation with an ophthalmologist.
Prevention of eye injuries is paramount anytime one could be exposed to small projectiles such as when working with wood or metal or participating in shooting sports or other outdoor activities.
Important historical information to obtain from the patient includes the details of the inciting event, setting of the injury, time of the incident, changes in vision, foreign body sensation in the eye, and pain.[8] The absence of foreign body sensation does not exclude the possibility that one may be present, and the patient still should be evaluated for foreign body. Penetration by small particle fragments may go unnoticed by the patient. Additionally, seemingly blunt objects still can cause lacerations if they contact the cornea in a certain orientation. In such cases, the patient may present for care later due to increasing pain, deterioration in vision, or infection. When trauma is present, it is important to inquire and screen for life-threatening injuries.
Obtain the patient's pre-injury vision history as well as previous ocular problems or ocular surgery.
Document pertinent medical history, current medications, allergies, and tetanus immunization status.
Determine information regarding the patient's last oral intake if operative intervention is anticipated.
Evaluation of visual acuity immediately following the injury is an important examination data point. Test visual acuity in each eye with a Snellen chart. If the patient cannot read a Snellen chart, document the ability of the patient to distinguish the number of fingers, movement, or light. This will assist the ophthalmologist in determining what sort of intervention, therapy, and rehabilitation may be required. Current visual acuity should be compared to the pre-injury visual acuity. Pinhole testing may help differentiate refractive error from uncorrectable vision when spectacles are not available. Use age-appropriate vision testing devices such as the Snellen distance chart or a hand-held vision card.
Ask the patient to identify typed letters, the clock, or objects on the wall if the patient's condition prevents formal (standing upright) testing.
When examining the orbit, care should be taken to avoid putting pressure on the globe. Instead, the examiner should place fingers on the orbital rim when retracting the eyelids. The bulbar conjunctiva typically will be injected with prominent blood vessels.
Using direct ophthalmoscopy, evaluate the lens for dislocation. Ensure that it is centered on the pupil.
Examine the cornea carefully, taking care not to apply additional pressure to the globe. Evaluate the cornea using a slit beam to search for anterior chamber penetration. A shallow anterior chamber, irregularly shaped pupil (teardrop shape), hyphema (blood in the anterior chamber), bubbles in the anterior chamber, or a flat cornea can be signs of corneal perforation.
Aqueous humor leaking from the anterior chamber can be identified by performing a Seidel test. This test is performed by directly applying fluorescein to the suspected corneal lesion. This requires 10% fluorescein. The patient should be informed not to blink so the examining physician can adequately visualize the tear film without it moving. Visualization of diluted or streaming dye under a black light (a positive test) suggests a leak. A negative Seidel test (no dilution of fluorescein) suggests a partial-thickness injury but may be seen in small or spontaneously sealing lesions. One should avoid the temptation to press on the globe to test for a self-sealing injury, as it can extrude globe content and lead to a worse outcome.
Be sure to evaluate for a foreign body in the anterior chamber, especially if the patient’s history suggests that the corneal laceration is from a small, high-speed object (ie, from hammering metal).
The most common location for corneal laceration is the inferior aspect of the globe. This is due to the Bell phenomenon (also known as palpebral oculogyric reflex), the upward and outward reflex rotation of the globe during blinking as a protective mechanism against the entrance of foreign material.[9]
Ophthalmology consultation is required for all types of corneal perforation.
The causes of corneal lacerations are numerous and include but are not limited to flying metal fragments, sharp objects, fingernails, air-bag deployment, fireworks, explosions, blunt force trauma, pellets, and BBs.[10, 11, 12, 13]
Corneal lacerations frequently are complicated by corneal or intraocular foreign bodies, infections, traumatic cataracts, and secondary glaucoma.
No laboratory studies are useful for detecting the presence of a corneal laceration.
Radiography, CT, or MRI may be indicated to identify intraocular or intraorbital foreign bodies or associated orbital, cranial, or facial trauma. MRI should generally be avoided if there is suspicion for a metallic foreign body. However, it may be of some use if organic foreign body (eg, wood, plant matter) is suspected.[11] MRI may be difficult to obtain on an emergent basis.
Thin-slice CT scanning is the preferred imaging modality for evaluation of suspected globe rupture. CT scanning also can be used to evaluate for other forms of associated head or facial trauma.
The globe and its contents can be imaged via ultrasonography. When using ultrasonography, plenty of gel should be applied to the eye so that the examining physician can place the probe in the gel but avoid putting pressure on the eye itself. Ultrasonography can be used to evaluate for globe rupture, lens dislocation, foreign body, retrobulbar hemorrhage, and retinal detachment. However, ultrasonography is contraindicated when globe rupture is suspected.[14] A 2002 study showed that ultrasonography has a sensitivity of 100% and specificity of 97.2% in diagnosing orbital pathology such as globe rupture, retrobulbar hemorrhage, retinal detachment, and lens dislocation.[15]
Radiography may be used to evaluate for additional facial fractures. However, many facilities have CT scanning readily available, which is more sensitive for finding such injuries.
Slit lamp biomicroscopy is essential.
Ultrasound biomicroscopy (UBM) may be performed to confirm architecture of the laceration.[16] UBM is a noninvasive diagnostic tool that provides in vivo imaging of the anterior segment in high resolution and with great depth of penetration. It allows visualization of the structures posterior to the iris.[17]
Anterior-segment optical coherence tomography (ASOCT) generates in vivo, high-resolution, cross-sectional imaging and is used to evaluate the structure of the anterior chamber.[18] It also can be used to detect the extent of a laceration and presence of globe rupture. As opposed to UBM, ASOCT cannot visualize structures posterior to the iris such as the ciliary body, zonules, and the peripheral lens.[19]
Cover the patient's eye with an eye shield or polystyrene/paper cup and avoid any pressure to the globe.
Instruct the patient to move the eyes as little as possible.
Administer antiemetic and analgesic medication in order to reduce pressure on the globe.
Perform an examination to ascertain the extent of the corneal, anterior chamber, ocular, and associated injuries (eg, facial, cranial).
Ophthalmologic consultation is indicated to address the practitioner's findings and to decide on the appropriate treatment and timing of ophthalmologic evaluation.
Place a protective eye shield (prefabricated or custom made) on the injured eye. This can be a commercial plastic eye shield or simply a polystyrene/paper cup taped over the eye. Do not use an eye patch.
Administer antiemetics and systemic analgesic medication.
Primary tetanus immunization or booster is indicated.
In consultation with the ophthalmologist, discuss the administration of antibiotics including route (topical or intravenously) and frequency.
In general, topical analgesia and antibiotics should be avoided if a corneal laceration is suspected or confirmed. Use systemic analgesia and antibiotics. Topical anesthetics may be used, if needed, to facilitate visual acuity testing and the slit lamp examination.
Prompt consultation with an Ophthalmologist is both indicated and necessary for further definitive management. An ophthalmologist will determine the best form of management, which may include the administration of antibiotics and surgical intervention.
For a small self-sealing corneal laceration, a bandage adhesive soft contact lens may be applied for approximately 3-6 weeks.[20] The adhesive lens will be kept in place in addition to a protective shield until the area heals.
Tissue adhesives have also been used with good success.[20] This should be reserved for select small puncture wounds and lacerations with little to no loss of central tissue. Cyanoacrylate glue can be used to repair small corneal lacerations. Fibrin glue has been found to be a safe and effective alternative to sutures in some cases of corneal lacerations.[21]
Surgical management usually is required to repair a corneal laceration, remove foreign bodies, and prevent further damage. The goal is to create a watertight wound, minimize scarring, and restore normal anatomic relationship.
Patients with corneal laceration may develop retinal detachment, infection, secondary glaucoma, phthisis bulbi, and/or vision loss.
Postoperative complications include corneal scarring, pigmentation, cataract formation, and endophthalmitis.[6]
Patients that engage in activities that place their eyes at risk for trauma should be encouraged to wear protective eyewear at all times.
Small full-thickness corneal lacerations require careful outpatient follow-up similar to partial thickness corneal injuries.
Definitive care is determined at the time of the initial ophthalmologic consultation and will take place in the setting of the patient’s overall condition.
A patient who sustains a corneal laceration as part of other trauma may have to be evaluated in the hospital for the other injuries.
Larger full-thickness lacerations require hospitalization, surgical management, and intravenous antibiotics.
Recommendations include a combination of a third-generation cephalosporin (eg, ceftazidime or ceftriaxone) and vancomycin.[22] In patients with a penicillin allergy, fluoroquinolone (ie, levofloxacin) can be used in place of cephalosporin. Clindamycin can be added if an intraocular foreign body is present or if vegetation has contaminated the wound. The most common organisms identified in posttraumatic endophthalmitis are Staphylococcus epidermidis, bacilli species, streptococci species, and gram-negative species. Fungal endophthalmitis is a relatively rare entity but should be considered in a patient who is recently post-surgical, immunocompromised, unresponsive to antibiotic treatment, or has a history of trauma with vegetable matter. Treatment should be discussed with the ophthalmology consultant if this is suspected.
Clinical Context: Potent antibiotic directed against gram-positive organisms and active against enterococci species.
Provides coverage for most gram-positive organisms causing endophthalmitis.
Used as prophylaxis in conjunction with a third-generation cephalosporin, or fluoroquinolone in penicillin-allergic patients.
To avoid toxicity, the current recommendation is to assay vancomycin trough levels after the third dose (drawn 0.5 h prior to next dosing). Use creatinine clearance to adjust the dose in patients with renal impairment.
The patient should be given systemic antibiotics and NSAIDs. Also, consider steroids and cycloplegics.
The decision to use steroids is at the physician’s discretion and should be made in conjunction with the ophthalmologist. The purpose of using steroids is to decrease inflammation; however, it also increases the risk of infection.
Cycloplegics and NSAIDs help to decrease pain.
Clinical Context: Lincosamides are useful as a treatment against serious skin and soft tissue infections caused by most staphylococci. They are also effective against aerobic and anaerobic streptococci, except enterococci.
Use in the prophylaxis of endophthalmitis when a foreign body is present, or if the injury was soil or farm related to provide an effective agent against bacilli species.
Clinical Context: Aminoglycoside that provides coverage for most gram-negative organisms causing endophthalmitis.
Commonly used in combination with both an agent against gram-positive organisms and one that covers anaerobes.
Gentamicin is not the antibiotic of first choice. Consider using this aminoglycoside when penicillins or other less toxic drugs are contraindicated, when bacterial susceptibility tests and clinical judgment indicate its use, and in mixed infections caused by susceptible strains of staphylococci and gram-negative organisms.
Dosing regimens are numerous and are adjusted based on creatinine clearance and changes in the volume of distribution. Gentamicin may be administered IV or IM.
These agents are used in prophylaxis of endophthalmitis. Therapy must cover all likely pathogens in the context of the clinical setting.
Clinical Context: It inhibits bacterial wall synthesis and provides good gram-negative coverage. Routes of administration include intramuscular, intravenous, or intravitreal. It is often used in conjunction with Vancomycin.
Clinical Context: It inhibits bacterial wall synthesis and provides coverage for gram-negative organisms. It can be administered as an intravenous or intramuscular medication. Ceftriaxone can be combined with vancomycin
Clinical Context: It promotes DNA break in susceptible organisms. It can be used as an alternative to cephalosporin in patients who are penicillin allergic in combination with vancomycin. It can be administered intravenously or orally.