Treating Corneal Abrasions and Lacerations
Bruce M. Zagelbaum, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 3 - MARCH 97
In Brief: Corneal abrasions and lacerations injure the 'windshield' of the eye, exposing the patient to potential vision loss and infection. Diagnosis rests on physical examination of the eye, using fluorescein stain and a penlight; further examination with a slit lamp is often required for lacerations. Treatment of abrasions includes application of topical antibiotics and—except in contact-lens users and perhaps with certain small abrasions—patching the eye. Lacerations require urgent referral to an ophthalmologist, who usually repairs the defect surgically. Topical anesthetics, though effective pain relievers, should never be prescribed for home use.
Corneal abrasions are one of the most common sports-related eye injuries seen, and they account for a large number of emergency eye examinations. In Major League Baseball, 33% of all eye injuries are corneal abrasions (1); in the National Basketball Association, corneal abrasions account for 12% of all eye trauma (2). Most corneal abrasions heal well, rarely resulting in ocular morbidity. More serious are corneal lacerations. They are not as common, but, depending on their severity, they may result in vision loss.
The cornea is the clear windshield of the eye. It has two major functions: (1) to refract light coming into the eye, helping to focus images directly on the retina, and (2) to act as a protective barrier from organisms (eg, bacteria) entering the eye. The cornea is approximately 11.6 mm in diameter horizontally and 10.5 mm vertically. The center is 0.55 mm thick and the periphery is nearly 1 mm thick. Viewed from the front, the cornea is convex.
The cornea has five distinct layers. From the outermost inward, these are the epithelium, Bowman's membrane, stroma, Descemet's membrane, and endothelium. The stroma accounts for 90% of corneal thickness and is composed of collagen fibers. The uniform spacing of the collagen fibers within the stroma accounts for the cornea's transparency. No blood vessels normally exist within the cornea. Its nutrition is mostly derived from the vascular limbus and from atmospheric oxygen. Lymphatic drainage is absent.
The corneal epithelium prevents organisms from entering the eye. It is approximately 50 micrometers thick. Any trauma to the epithelium may allow bacteria to penetrate the cornea, creating a corneal infiltrate (ulcer).
Bowman's layer measures nearly 10 micrometers its function is unknown. The endothelium consists of a single layer of cells that acts as a pump to keep the cornea deturgescent.
The first division of the trigeminal nerve (cranial nerve V), the ophthalmic division, innervates the cornea via the long and short ciliary nerves. Because there are nerve endings in close proximity to the corneal epithelium, even slight exposure, as with corneal abrasion, may result in significant pain.
Corneal abrasions are frequently seen in eye trauma victims. Generally, they result from a blunt or projectile object striking the front of the globe. The corneal epithelium dislodges and renders the underlying layers susceptible to bacterial infection.
Signs and symptoms. A corneal abrasion may produce significant pain, tearing, light sensitivity (photophobia), foreign body sensation, and decreased visual acuity. Signs may include conjunctival injection (redness), iritis (anterior chamber inflammation), and eyelid swelling.
Diagnosis. As is customary with eye trauma patients, the initial evaluation must be completed in a timely manner, as rapid diagnosis and appropriate treatment are essential to optimize the outcome. Even if it appears evident that an injury was sustained to one eye, both eyes should always be examined.
The cornea may be examined with a penlight, checking for clarity and the presence of an abrasion, laceration, or foreign body. Corneal abrasions are easily identified by using fluorescein stain with or without topical anesthetic and a cobalt blue filter for the penlight (see figure 1 for technique).
If blunt trauma has caused significant eyelid edema, special care should be taken not to apply pressure to the globe. Swollen eyelids may be opened by gently placing a finger on them and stretching the skin upward (for the upper eyelid) and downward (for the lower eyelid). With the skin at the superior or inferior orbital rim, pressure may be applied against the bone to expose the cornea.
Treatment. A topical broad-spectrum antibiotic (eg, tobramycin ophthalmic ointment) should be instilled into the affected eye, and—except in contact-lens users—a pressure patch should be applied (see figure 2 for technique). A mydriatic or cycloplegic agent (eg, 1% cyclopentolate hydrochloride) may also be given for comfort for moderate to severe abrasions or if associated iritis is present.
The patient should be examined daily until the cornea has regenerated, which generally occurs within 48 to 72 hours. Each day, the patch is removed, and the corneal abrasion is reassessed. If the abrasion is still present, antibiotic ointment is reapplied, along with a new pressure patch. Once the abrasion has healed, topical antibiotic drops may be continued for a few days.
If a corneal abrasion occurs in a contact lens user, patching should be avoided, as such patients are at increased risk of infectious keratitis, most commonly from Pseudomonas aeruginosa. Treatment should consist of a topical antibiotic with good gram-negative coverage (eg, ofloxacin or tobramycin). Contact lenses should not be worn in an eye with a corneal abrasion. The only exception is a therapeutic "bandage lens" used to promote healing.
Clinicians should take each case individually and use their best judgment regarding treatment. Although the method of pressure patching has been around for many years, a recent study (3) questioned its necessity for certain abrasions. Kaiser concludes that small, noninfected, non-contact-lens-related traumatic corneal abrasions, as well as abrasions secondary to foreign body removal, may be treated with antibiotic agents and mydriatics alone. He continues to recommend pressure patching for larger abrasions.
On diagnosing a corneal abrasion, the use of a topical local anesthetic (eg, 0.5% tetracaine hydrochloride) provides the patient with significant temporary relief. However, it is important to understand that topical anesthetics should never be dispensed to a patient. Their continued use may result in severe ocular morbidity, including persistent epithelial defects, permanent corneal damage, and vision loss (4).
Corneal lacerations (figure 3) usually result from a sharp projectile injury or blunt trauma. While an abrasion can be considered a scrape, a laceration is an actual cut into the cornea.
Should a corneal laceration be suspected, a rigid protective shield should be applied to the injured eye (figure 4). This protects against inadvertent pressure on the eye that could result in the extrusion of intraocular contents. Prompt evaluation and treatment by an ophthalmologist is then required.
Diagnosis is most easily made using a slit lamp. However, corneal lacerations can be recognized during the penlight examination by observation of a flat anterior chamber or tissue (iris) protruding through the cornea. If a sharp object such as a knife, razor, or glass was involved in the trauma, corneal laceration should be suspected.
Because surgical repair is generally indicated, the patient should be allowed nothing by mouth. Antiemetics and analgesics are given to avoid vomiting and agitation. The primary goals in repairing a corneal laceration are to restore the normal ocular anatomy by obtaining a watertight closure of the eye and to maintain structural integrity while minimizing the risk of infection (5).
Partial-thickness laceration. If a corneal laceration is partial thickness (nonpenetrating), treatment varies. The goal is to prevent infection and promote re-epithelialization and stromal healing.
If the wound edges are well apposed, a pressure patch and prophylactic topical antibiotics may be adequate. For a nondisplaced, beveled laceration with a formed anterior chamber and no tissue (ie, iris) incarceration, a bandage contact lens may be used to support the wound. The lens helps promote re-epithelialization by protecting the wound against eyelid movement. The lens is kept on until the wound has healed and complete re-epithelialization has occurred. Use of bandage contact lenses renders sutures unnecessary, which is particularly advantageous if the visual axis is involved, and allows for frequent topical medication application. However, a contact lens should be used only when the wound is well apposed. For poorly apposed wounds, or if tissue is missing, 10-0 nylon sutures are placed in an operating room and systemic antibiotics are begun.
Full-thickness laceration. Most corneal lacerations require the placement of corneal sutures by the ophthalmologist. Generally, surgical repair is performed in the operating room under general anesthesia. Many techniques are used. The characteristics and location of the laceration are important factors. Surgery is performed as soon after injury as possible, and the patient is generally placed on intravenous antibiotics. The combination of a cephalosporin (eg, cefazolin sodium) or vancomycin and an aminoglycoside (eg, gentamicin sulfate) provides good coverage against gram-positive bacteria and gram-negative organisms.
For a few lesions, other forms of treatment may suffice. Small, self-sealing corneal perforations may be adequately treated with a bandage contact lens along with topical antibiotics. Tissue adhesive, also known as corneal glue, has also been used by ophthalmologists; it is most helpful in small puncture wounds that involve minimal tissue loss. Once the adhesive is applied, a bandage contact lens is placed for patient comfort and to prevent dislodging of the adhesive. Prophylactic topical antibiotics are used.
It is recommended that all corneal abrasions be evaluated by a physician as soon as possible. The patient should be followed daily and referred to an ophthalmologist if healing has not occurred within 48 hours, or if the wound worsens in any way. Suspected corneal lacerations need an ophthalmologist's evaluation and treatment immediately for best results. For all corneal injuries, both patient compliance and careful follow-up by the physician must be emphasized. With proper attention, though, most corneal injuries will resolve without complications.
Dr Zagelbaum is an ophthalmologist affiliated with North Shore University Hospital in Manhasset, New York, and is the team ophthalmologist for the New York Mets, the New York Islanders, and the Department of Athletics at St John's University in Jamaica, New York. He is author of the textbook Sports Ophthalmology and is the principal investigator on eye trauma studies involving the National Basketball Association and Major League Baseball. Dr Zagelbaum, a fellow of the American College of Surgeons, is on the editorial board of The Physician and Sportsmedicine. Address correspondence to Bruce M. Zagelbaum, MD, FACS, 333 E Shore Rd, Suite 202, Manhasset, NY 11030; e-mail to [email protected].
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