Corneal abrasions and corneal foreign bodies: Clinical manifestations and diagnosis

INTRODUCTION — Corneal abrasions are common eye injuries that frequently result from eye trauma, foreign bodies, and improper contact lens use. Patients typically present with severe eye pain and a foreign body sensation. Key aspects of clinical evaluation include exclusion of an open globe and hyphema, measurement of visual acuity, penlight and fluorescein examination, and lid eversion to assess for a conjunctival foreign body. Treatment of small, uncomplicated corneal abrasions consists of topical antibiotic therapy and either topical or oral pain medication. Most abrasions heal fully within 24 hours.

This topic will review the etiology, clinical presentation, diagnosis, and differential diagnosis of corneal abrasions. The management of corneal abrasions, the general approach to a patient with red eye, and the assessment and management of other ocular injuries are discussed separately:

●(See "Corneal abrasions and corneal foreign bodies: Management".)

●(See "The red eye: Evaluation and management".)

●(See "Open globe injuries: Emergency evaluation and initial management".)

●(See "Traumatic hyphema: Clinical features and diagnosis".)

●(See "Traumatic hyphema: Management".)

●(See "Conjunctival injury".)

●(See "Topical chemical burns: Initial evaluation and management".)

TERMINOLOGY — Corneal abrasion is often used to refer to any defect in the corneal surface epithelium (figure 1). However, this is an inexact use of the term because it also implies etiology. Many corneal abnormalities are more appropriately called "corneal epithelial defects," while corneal abrasion more strictly refers to a defect in the epithelial surface of the cornea that is caused by mechanical trauma to the surface of the eye. Nevertheless, since "corneal epithelial defect" is not a term in general usage by patients and providers, we will use both terms interchangeably to refer to corneal epithelial defects of all etiologies.

Corneal abrasions can be classified as traumatic (including foreign body related or contact lens related) or spontaneous as follows:

●Traumatic – Traumatic corneal abrasions are often caused by fingernails, paws, pieces of paper or cardboard, make-up applicators, hand tools, branches, and leaves, or by a foreign body that has lodged under the lid.

Special types of traumatic abrasions include the following:

•Foreign body – Foreign body related abrasions are defects in the corneal epithelium that are left behind after the removal or spontaneous dislodging of a corneal foreign body. Foreign body abrasions are typically caused by pieces of rust, wood, glass, plastic, fiberglass, or vegetable material that have become embedded in the cornea.

•Contact lens – Contact lens related abrasions are defects in the corneal epithelium that are left behind after the removal of an over-worn, improperly fitting, or improperly cleaned contact lens. These eyes have suffered a mechanical insult that is not from external trauma, but rather from a foreign body (contact lens) that is associated with specific pathogens.

●Spontaneous – Spontaneous defects in the corneal epithelium may occur with no immediate antecedent injury or foreign body. Eyes that have suffered a previous traumatic abrasion or eyes that have an underlying defect in the corneal epithelium (eg, epithelial basement membrane dystrophy [map-dot-fingerprint dystrophy], Thiel-Behnke dystrophy, or lattice dystrophy) are prone to this problem. Spontaneous corneal abrasions are also known as recurrent erosions.

EPIDEMIOLOGY — Corneal abrasions are common, accounting for 8 to 13 percent of eye presentations, depending upon the setting (eg, primary care offices, emergency departments, or dedicated eye emergency departments) [1-4].

Corneal abrasions cause significant morbidity and lost productivity. As an example, a study of eye injuries in a major United States automotive corporation found an annual incidence of 15 eye injuries per 1000 employees [5]. The eye injuries comprised 6 percent of total injuries, and corneal foreign bodies and abrasions were 87 percent of the eye injuries. One-third of eye injuries resulted in the inability of workers to resume normal duties for at least one day. In another report, most patients with corneal foreign bodies did not take more than one day off work, and up to 30 percent sought treatment outside of working hours to avoid lost time from work [6]. Almost all of these injuries could have been avoided with the use of safety glasses.

CLINICAL MANIFESTATIONS — The corneal epithelium is richly innervated with sensory pain fibers from the trigeminal nerve (cranial nerve V). Thus, patients with corneal abrasions of all types have the same clinical presentation; severe eye pain and reluctance to open the eye due to photophobia and/or foreign body sensation. Often patients are too uncomfortable to work, drive, or read, and the pain frequently precludes sleep. Multiple attempts by the patient to "wash out" the eye can further disrupt the epithelial surface.

A complaint of eye pain and objective evidence of photophobia and/or foreign body sensation (eg, observation that the patient is keeping the affected eye shut) together are highly suggestive of a pathologic process of the cornea, although no formal studies of the sensitivity and specificity of these findings have been performed. The exception is patients with dysfunction of cranial nerve V due to trauma, tumor, or prior infection with Herpes Simplex or Varicella Zoster (shingles); these individuals may have corneal defects with no pain.

History — The history typically identifies the etiology of the abrasion. (See 'Terminology' above and "Corneal abrasions and corneal foreign bodies: Management", section on 'Terminology'.)

●Patients with traumatic abrasion have a history of direct trauma to the globe followed almost immediately by severe pain, photophobia, and foreign body sensation.

●Patients with a foreign body may or may not recall an episode with material falling or flying into the eye, depending upon the type and size of the foreign body. Symptoms of pain and foreign body sensation may not be immediate. Alternatively, the sensation may be immediate, then abate for a while, then recur. If the foreign body entered the eye at high velocity, as may be the case when using a grinding machine or from metal striking metal, the examiner must consider the possibility of a penetrating eye injury and modify the subsequent examination as clinical findings require. (See 'Excluding penetrating trauma' below.)

●Other relevant points of history include whether the episode is associated with contact lens wear or, in the case of apparently spontaneous abrasions, whether there is history of prior traumatic abrasion. Specific historical features include:

•Patients with contact lens related abrasions frequently report sleeping in their contacts and awakening with eye pain and photophobia. Patients may also report poor hygiene practices (eg, use of improper wetting solutions, improper maintenance of contact lens cases, difficulty with contact lens fit, or exceeding recommended wear time). (See "Complications of contact lenses", section on 'Incidence and risk factors'.)

•Patients with recurrent erosion syndrome tend to awaken in the middle of the night with searing eye pain, or they develop the pain upon first awakening in the morning with attempt to open the eyes. This description is diagnostic of recurrent erosion syndrome.

Eye examination

Preparation and analgesia — Patients may have had severe pain for several hours by the time they seek care. They are visibly uncomfortable, pacing or rocking or rubbing the eye, and they can be disruptive to a waiting room. During the initial triage period, they should be offered a darkened room in which to wait, asked to wait quietly with the eyes closed, and encouraged not to rub the eye.

Based upon studies in animals, topical anesthetics can be toxic to the epithelium and retard healing which may increase the risk of corneal infection and scarring [7]. Thus, the eye examination is best performed without topical anesthesia, when the patient can tolerate it. However, in children, topical anesthesia is frequently needed for cooperation. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Treatments to avoid' and 'Pediatric considerations' below.)

For the patient who is too uncomfortable to cooperate with examination, a penlight examination to confirm that there is no evidence of penetrating trauma should be performed, and then one drop of topical anesthetic (proparacaine 0.5 percent solution) may be instilled to facilitate the measurement of visual acuity and the subsequent examination. The patient will obtain drastic relief within 10 seconds of the instillation and will likely ask for additional doses after the drop wears off in 10 to 20 minutes. In this situation, the clinician should explain the negative effects of repeated administration of topical anesthesia and provide alternative forms of analgesia. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Pain control' and "Corneal abrasions and corneal foreign bodies: Management", section on 'Treatments to avoid'.)

Excluding penetrating trauma — In adults in whom the history raises the possibility of penetrating trauma, and in children in whom the history may be unreliable, the initial examination must exclude penetrating trauma.

If the patient is unable to voluntarily open the eye, the lids are gently pulled apart or the upper lid lifted, avoiding pressure on the globe. The pupil should be confirmed to be round and central. On direct inspection with a penlight, the anterior chamber should appear grossly clear, deep, and of normal contour. In corneal abrasion, the pupil is typically small (reactive miosis). Pupillary constriction in response to light may be difficult to detect in the presence of reactive miosis.

A large nonreactive pupil or an irregular pupil suggests injury to the pupillary sphincter from penetrating trauma with an open globe (picture 1 and picture 2) or significant blunt trauma with an associated hyphema (picture 3). These findings warrant further evaluation and prompt ophthalmologic consultation. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral'.)

The rapid overviews provide key diagnostic findings and initial management for patients with open globes and traumatic hyphemas (table 1 and table 2). (See "Open globe injuries: Emergency evaluation and initial management" and "Traumatic hyphema: Clinical features and diagnosis" and "Traumatic hyphema: Management".)

Visual acuity — Abrasions within the visual axis and other serious injuries associated with corneal abrasions may significantly impair visual acuity. Acuity should be measured before instillation of fluorescein drops and without the aid of a topical anesthetic, whenever possible, to assess for profound vision loss caused by penetrating trauma. Otherwise, administration of anesthetic drops or fluorescein dye risks further disruption of ocular structures if an open globe is present. On the other hand, a child with an abrasion may not be able to cooperate for measurement of visual acuity without instillation of topical anesthetic; anesthetic drops may be appropriate in this situation if the suspicion for penetrating trauma is low. Patients with impaired visual acuity warrant prompt consultation with an ophthalmologist. (See 'Preparation and analgesia' above and 'Fluorescein examination' below.)

Visual acuity may be normal (20/20 feet or 6/6 meters) if the abrasion is away from the visual axis. It might be slightly subnormal, in the 20/25 (6/7) to 20/40 (6/12) range, if the abrasion is in the visual axis, or it might be substantially subnormal (as low as 20/400 [6/120]) if the abrasion is in the visual axis and there is corneal edema.

Corneal edema tends to develop in abrasions that have been present for more than 12 hours after the patient continually rubs or presses on the eye in response to pain. Corneal edema causes the cornea to have a hazy gray appearance rather than a distinct infiltrate.

Referral to an ophthalmologist is warranted if the primary care provider is not certain that he or she can distinguish corneal haze from an infiltrate in the patient with an "abrasion" who has substantially reduced acuity; an infectious infiltrate can have sight-threatening consequences if not diagnosed, treated, and monitored properly. A corneal infiltrate may not affect acuity if it is out of the visual axis; thus, acuity alone is not sufficient to distinguish infiltrate from haze. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral'.)

Penlight examination — Pupils can be assessed with the penlight examination. However, the pupil is sometimes quite small in a patient with an abrasion, making it difficult to detect a light response. The penlight examination should be completed before instillation of fluorescein dye. (See 'Fluorescein examination' below.)

The chamber should have a normal contour and the pupil should be round. The penlight examination will reveal mild conjunctival injection if the abrasion is more than an hour or two old; there may be ciliary flush if it is more than several hours old. With ciliary flush, injection is most marked at the limbus (where the cornea undergoes transition to the sclera) and then diminishes toward the equator. There should also be no discharge other than tears, and no infiltrate, corneal opacity (picture 4 and picture 5 and picture 6), or hypopyon (pus in the anterior chamber (picture 7 and picture 8)). The edges of the abrasion can usually be detected by the disruption that it causes to the corneal light reflex. A foreign body also often can be detected at this time by direct visualization with the penlight. Any patient with a suspected corneal infiltrate, opacity, or pus (hypopyon) in the anterior chamber should also be examined that day by an ophthalmologist. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral'.)

A flat chamber, a chamber full of blood (hyphema), or an irregular pupil increases suspicion of a penetrating eye injury and warrants prompt ophthalmologic consultation. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral' and "Open globe injuries: Emergency evaluation and initial management", section on 'Physical examination' and "Traumatic hyphema: Clinical features and diagnosis", section on 'Findings of hyphema'.)

Extraocular movements — Eye motility should also be assessed and should not result in any pain or double vision.

Funduscopic examination — A funduscopic examination should be attempted, at least to confirm a red reflex. However, visualization of fundus detail may be difficult due to a small pupil and photophobia and may not be possible in young children. (See "The pediatric physical examination: HEENT", section on 'Eyes'.)

Fluorescein examination — A working diagnosis of corneal abrasion should be made based upon the history, physical findings, and lack of signs of other disorders. Fluorescein examination should be performed to confirm the diagnosis only after completion of visual acuity measurement and the penlight and fundus examination. Earlier instillation of dye may interfere with visual acuity measurement and visualization of the anterior segment and fundus.

The fluorescein examination is performed as follows. The lower lid is pulled down, and a fluorescein impregnated paper strip is moistened with saline or topical anesthetic, allowing a drop to run off into the eye or the inferior cul-de-sac. When the patient blinks, the dye is distributed over the ocular surface. Alternatively, the strip is gently swiped against the bulbar or tarsal conjunctiva below the cornea and the patient is allowed to blink to distribute the fluorescein.

Fluorescein stains basement membrane, which is exposed in the area of the epithelial defect (figure 1). The affinity is quite high, so very little fluorescein is necessary. The stained abrasion appears yellow with the naked eye. Visualization is enhanced by the use of a cobalt blue filter (available on any ophthalmoscope or slit lamp) or a Wood's lamp. Foreign bodies may not stain, although the exposed edge of epithelium at the edge of the foreign body typically does. Clinicians who are examining with a slit lamp can look for a Seidel sign (streaming of fluorescein caused by leaking aqueous humor), which, if present, indicates penetrating trauma. (See "Slit lamp examination", section on 'Fluorescein examination for corneal abrasion' and "Slit lamp examination", section on 'Seidel's test'.)

The staining defect can appear linear or geographic depending upon the epithelial defect (picture 9). Defects from recurrent erosions have no specific diagnostic appearance. Sometimes a mobile flap of epithelium can be visualized.

Other causes of corneal epithelial defects may have specific staining patterns as follows:

●Retained conjunctival foreign body – Corneal epithelial defects caused by a retained conjunctival foreign body under the lid may have a characteristic appearance of multiple, parallel vertical lines at the upper edge of the cornea. (See 'Eyelid eversion' below.)

●Herpes simplex virus infection – A branching pattern suggests herpes simplex virus infection (picture 10). A nearly healed abrasion may have a branching appearance as the defect closes in, but this patient will have resolution of symptoms in 24 hours while the patient with a herpes dendrite will not. A further distinction is that the patient with a herpes dendrite can report no specific antecedent injury, and there may be a history of prior episodes of herpes keratitis. (See "Herpes simplex keratitis", section on 'Clinical manifestations'.)

Skilled ophthalmologists sometimes have difficulty distinguishing a herpes dendrite from a healing abrasion (pseudo-dendrite) and will occasionally monitor for 24 to 48 hours to distinguish the two. An “abrasion” with branching pattern, particularly one that is failing to improve over 24 to 48 hours, warrants prompt ophthalmic evaluation.

●Contact lens abrasions – Contact lens associated staining defects tend to be round and central, sometimes encompassing the entire cornea. Typically, there is punctate breakdown that has become contiguous. The punctate pattern may be apparent immediately upon instillation of fluorescein, but will be more difficult to discern as the fluorescein diffuses through the cornea. (See "Complications of contact lenses", section on 'Corneal epithelial problems'.)

●Airbag deployment – Airbag deployment may result in large corneal abrasions [8]. In some patients, the nylon mesh pattern of the deployed airbag can be seen. Blunt eye trauma from airbag deployment is also associated with traumatic hyphemas. (See "Traumatic hyphema: Clinical features and diagnosis", section on 'Mechanism of injury'.)

●Microbial keratitis and contact lens-associated corneal infiltrates – These tend to be round on fluorescein staining and are typically evident as a white or opaque spot with a penlight or direct inspection (picture 4 and picture 5 and picture 6).

Fluorescein exam with a Wood's lamp (and likely same for cobalt filter on ophthalmoscope) is not as sensitive as slit lamp for detecting corneal pathology [9]. Slit lamp examination, if available, is preferred for initial assessment and is certainly warranted if symptoms persist after initial treatment. (See "Slit lamp examination", section on 'Fluorescein examination for corneal abrasion'.)

Eyelid eversion — After the diagnosis of abrasion is confirmed with fluorescein, the clinician should flip the upper lid to assess for the presence of a retained foreign body (movie 1). Retained foreign bodies typically lodge in the pretarsal sulcus of the upper lid (picture 11) and can cause an abrasion with a characteristic appearance of multiple parallel vertical lines at the upper edge of the cornea. However, the inexperienced observer may not be able to distinguish this pattern from that of any other abrasion. If the lid foreign body has been present for several hours or if time has elapsed since the instillation of fluorescein, the parallel lines may become contiguous, confounding even the experienced observer. Thus, lid eversion should still be performed even if the characteristic pattern is not observed.

DIAGNOSIS — Any patient who complains of severe eye pain with photophobia and foreign body sensation preventing opening of the eye generally can be presumed to have a corneal epithelial defect. The provider must then exclude penetrating trauma and an infectious infiltrate. Once an open globe or corneal infectious ulcer is excluded, the working diagnosis is then confirmed by demonstration of the defect on fluorescein staining. (See 'Eye examination' above and 'Fluorescein examination' above.)

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of corneal abrasion includes serious conditions that require ophthalmologic evaluation (table 3) and treatment and more benign conditions that can be managed by a primary care provider (table 4). Features that can help distinguish these include history, visual acuity, sensation of a foreign body, photophobia, discharge, pupil size and reactivity, pruritus or pain, and fluorescein staining as summarized in the table (table 5).

The evaluation of the red eye is discussed in detail separately. (See "The red eye: Evaluation and management", section on 'Patient evaluation' and "The red eye: Evaluation and management", section on 'Angle-closure glaucoma'.)

INDICATIONS FOR SUBSPECIALTY CONSULTATION OR REFERRAL — The indications for consultation or referral to an ophthalmologist including findings that indicate emergent or prompt evaluation are discussed separately. (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral'.)

MANAGEMENT — The management of corneal abrasions and foreign bodies is discussed in detail separately. (See "Corneal abrasions and corneal foreign bodies: Management".)

PEDIATRIC CONSIDERATIONS — Corneal abrasions present in the pediatric population similarly to those in adults. However, the history is typically less specific. As an example, an infant who suddenly becomes irritable with symptoms in one eye may have scratched the cornea with a fingernail. Any time a child cannot or will not open an eye, penetrating trauma must be ruled out; a negative history from the child or a caretaker should not be relied upon in this situation. However, most cases of penetrating trauma will involve circumstances that suggest the possibility of such an injury (eg, injury involving a projectile, broken glass, etc). (See 'Excluding penetrating trauma' above.)

If there is no evidence of penetrating trauma, an attempt can be made at measuring visual acuity with a technique appropriate to the age of the child. (See "Vision screening and assessment in infants and children".)

If the exam is difficult, a single drop of topical ophthalmic anesthetic may be instilled to facilitate the remainder of the exam. The child and the caregivers should be warned that the drops will sting. (See 'Visual acuity' above.)

In children, given that the history is unreliable, it is always important to inspect the lower cul-de-sac and to then flip the upper lid for direct visualization of the mucosal surface. A foreign body can be swept away with a cotton swab. Since a foreign body may be very small or light in color, it may be helpful to wipe the inner surface of the lid with a moistened swab even if no foreign body is visualized. (See 'Eyelid eversion' above and "Corneal abrasions and corneal foreign bodies: Management", section on 'Foreign body removal'.)

The remainder of the examination is performed as in an adult, including lid eversion and fluorescein staining (see 'Eye examination' above). If a funduscopic examination is not possible an attempt should be made to at least find a red reflex.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, “The Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)

●Basics topics (see "Patient education: Corneal abrasion (The Basics)" and "Patient education: Chemical eye injury (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Causes of abrasions – Corneal abrasions are defects in the corneal epithelium that can be classified as traumatic, including foreign body and contact lens related, or spontaneous. Traumatic corneal abrasions are most common and are often caused by fingernails, paws, pieces of paper or cardboard, makeup applicators, hand tools, branches, leaves, foreign bodies lodged under the eyelid, and contact lenses. (See 'Terminology' above and 'Epidemiology' above and "Corneal abrasions and corneal foreign bodies: Management", section on 'Terminology'.)

●Clinical manifestations – Patients with corneal abrasions of all types typically complain of excruciating eye pain and an inability to open the eye due to photophobia and/or foreign body sensation. Often patients are too uncomfortable to work, drive, or read, and the pain frequently precludes sleep. (See 'Clinical manifestations' above.)

●Differential diagnosis – The differential diagnosis of eye pain, photophobia, and/or foreign body sensation includes serious conditions that require ophthalmologic evaluation (table 3) and more benign conditions (table 4). In most patients, clinical findings provide the correct diagnosis (table 5). (See 'Differential diagnosis' above.)

●Diagnosis – Any patient who complains of severe eye pain with photophobia and/or foreign body sensation preventing opening of the eye should be suspected to have a corneal epithelial defect. Demonstration of corneal defect on fluorescein staining confirms the diagnosis (see 'Diagnosis' above). An algorithm to aid with the diagnosis is provided (algorithm 1).

•The provider must rule out penetrating trauma (table 1 and table 2 and picture 1 and picture 2), a bacterial ulcer (picture 4 and picture 5 and picture 6), and a hypopyon (picture 7 and picture 8). (See 'Excluding penetrating trauma' above and 'Fluorescein examination' above.)

•The following findings are typical of a corneal abrasion without penetrating eye injury (see 'Eye examination' above):

-Normal visual acuity (although acuity may be decreased if the abrasion is located in the visual axis)

-A round, reactive pupil associated with mild conjunctival injection, tears, and/or corneal defect but no infiltrate or corneal opacity

-Staining defect on fluorescein examination (picture 9)

•A branching pattern on fluorescein staining suggests herpes simplex virus keratitis (picture 10), which can appear similar to a nearly healed abrasion. (See "Herpes simplex keratitis", section on 'Clinical manifestations'.)

•After the diagnosis of abrasion is confirmed with fluorescein, the clinician should flip the upper lid to rule out the presence of a retained foreign body. Retained foreign bodies typically lodge in the pretarsal sulcus of the upper lid (picture 11) and can cause an abrasion with a characteristic appearance of multiple parallel vertical lines at the upper edge of the cornea. (See 'Eyelid eversion' above.)

●Indications for ophthalmology referral – Emergency ophthalmology referral is indicated for patients with a suspected open globe (picture 1 and picture 2 and picture 12 and picture 13 and picture 14).

Prompt evaluation by an ophthalmologist that day is also warranted for patients with a hyphema (picture 15), corneal opacity (picture 6), or hypopyon (pus layering in the anterior chamber (picture 7 and picture 8)). (See "Corneal abrasions and corneal foreign bodies: Management", section on 'Indications for subspecialty consultation or referral'.)