CORNEAL ABRASION AND RECURRENT CORNEAL EROSION

Corneal Abrasion

Recurrent Corneal Erosion

SIGNS AND SYMPTOMS
Symptoms of acute pain and a history of recent trauma are obviously the tell-tale indicators of a corneal abrasion, but the patient may also report photophobia, pain upon extraocular muscle movement, excessive tearing, blepharospasm, foreign body sensation and blurry vision. Slit lamp exam of the injured area may reveal diffuse corneal edema and epithelial disruption. In severe cases, when edema is excessive, you may see folds in Descemet’s membrane. With fluorescein staining, the newly created wound will appear as a bright green area compared to the rest of the cornea as the dye accumulates in the divot.

Recurrent corneal erosion (RCE) is characterized by repeated, spontaneous disruption of the corneal epithelium. In most cases, the malady is preceded by mechanical trauma, such as a corneal abrasion caused by a fingernail.

Patients with RCE usually present to the office with a history of corneal abrasion in the involved eye, often months or years previously, and a chief complaint of recurrent episodes of ocular pain that may also include foreign body sensation, photophobia, blepharospasm, decreased vision or lacrimation upon awakening or following eye rubbing or eye opening.

Clinical signs include a localized, visible roughening of the corneal epithelium which stains superficially with fluorescein dye. The lesions are typically unilateral and in the vicinity of the original corneal defect. Bilateral or idiopathic lesions suggest a basement membrane dystrophy. The phenomenon may occur as frequently as daily or as sparsely as biweekly or monthly.

Epithelial basement dystrophy is an associated finding in many cases. It is marked by small, intra-epithelial dots and subepithelial ridges and lines (“maps”, “fingerprints”), representing poor adhesion of the epithelial basement membrane and Bowman’s layer.

PATHOPHYSIOLOGY
There are two categories of abrasions: superficial (those not involving Bowman’s membrane) and deep (those that penetrate Bowman’s membrane, but do not rupture Descemet’s membrane). Abrasions may result from foreign bodies, contact lenses, chemicals, fingernails, hair brushes, tree branches, dust and the like.

The cornea has remarkable healing properties. The epithelium adjacent to any insult expands in size to fill in the defect, usually within 24 to 48 hours. Lesions that are purely epithelial often heal quickly and completely without scarring. Lesions that extend below Bowman’s are more likely to leave a permanent scar.

The epithelial healing process begins when basal epithelial cells undergo mitosis, producing new cells that occupy fresh wounds. Basal cells adhere the epithelium to the stroma in two ways: they secrete the basement membrane and they contain hemidesmosomes, which are essentially linchpins that protrude through the posterior surface of basal cells and into the stroma; each is held in place by an anchoring fibril. Any disruption to basal cell production will make the eye more prone to recurrent erosion.

MANAGEMENT
For a corneal abrasion, first evert the eyelid and scrutinize the palpebral conjunctiva, ocular surface and fornices to rule out the presence of foreign material. Instill fluorescein dye to identify the corneal defects. Next, use the Seidel test (painting the wound with dye and observing for aqueous leakage) to uncover possible full-thickness injuries. Document the size, shape, location and depth of the abrasion. Finally, evaluate the anterior chamber and perform a dilated fundus exam to check for other effects of the trauma.

Begin treatment with cycloplegia (atropine 1% for the worst cases, homatropine 5% for moderate cases and cyclopentolate 1% for the mildest) and a topical antibiotic such as Polytrim, gentamicin or tobramycin (Tobrex). Recommend bed-rest, inactivity and OTC analgesics. If pain is severe, prescribe a topical nonsteroidal anti-inflammatory (Voltaren, Acular or Ocufen, b.i.d. to q.i.d.) and/or a thin, low-water content bandage contact lens.

Today, pressure patching is somewhat controversial. When patients are not in a great deal of discomfort, most abrasions do not require patching. Larger abrasions may fare better with patching. The medicinal and homeostatic effects of patching help to keep patients still, quiet and more comfortable. Reevaluate the patient every 24 hours until the abrasion is re-epithelialized. Bandage soft contact lenses have nearly supplanted the traditional pressure patch in the management of corneal abrasions.

Treat recurrent erosions in much the same way. But bear in mind that, in this instance, larger defects may require patching. If pressure patching is unnecessary or contraindicated, prescribe a topical antibiotic drop q.i.d. with an antibiotic ointment at bed-time.

If the corneal epithelium is not healing properly within 24 to 48 hours, debride the area to give the epithelium a “clean slate” on which to regenerate. Instill a topical anesthetic, then remove the involved epithelium with a cotton-tipped applicator soaked in saline. Any of the above steps can be followed after the procedure.

The most severe, recalcitrant cases may require anterior stromal puncture (purposeful scarring of the involved area using a 23- to 25-gauge bent needle). This is accomplished by anesthetizing the cornea, then using the needle to puncture the epithelium to the levels of Bowman’s membrane or anterior stroma in the affected area.

The final step in managing RCE is hypertonic therapy. Sodium chloride drops and ointments (2% and 5%) applied to the eye q.i.d./q3h during the day and at bedtime will help to reduce corneal swelling, lubricate the corneal surface and promote epithelial adherence. Interestingly, they also may help to restore vision.

CLINICAL PEARLS

  • For both medical and legal purposes, it’s important to take and record a detailed case history before performing any procedures or treatments. Record the time, place and activity surrounding the injury, as well as the presenting visual acuities.
  • If the blepharospasm is sufficiently intense to preclude acuity testing, administer one drop of anesthetic and try again.
  • To promote healing, prevent recurrent erosion and reduce corneal edema, Rx a hypertonic solution or ointment along with the other medications after re-epithelialization. If excess epithelium impairs regrowth, use a cotton-tipped applicator saturated with anesthetic to debride loose tissue.
  • When there’s significant iritis present, Rx a steroid. Infiltrates may be a sign of infection or impending ulceration. Consider such presentations to be vision threatening, and treat immediately with a fluoroquinolone; also consider culturing the lesion.
  • Patients with recurrent erosion require constant monitoring. Frequent use of use of thick artificial tear drops and ointments will provide prophylactic lubrication and comfort. Bandage contact lens therapy is another good treatment option. Thin, low-water content, disposable lenses provide reasonable drug delivery while reducing the mechanical shearing forces on non-ulcerative, corneal epithelial lesions.
  • Collagen punctal plugs may help identify individuals who would benefit from punctal occlusion or punctal cautery.
  • In cases of recalcitrant recurrent erosion, particularly those with vision-reducing corneal scars, consider phototherapeutic keratectomy using an excimer laser, as well as diamond burr debridement and anterior stromal puncture.

Other reports in this section

Eyelids & Eyelashes | Conjunctiva & Sclera | Cornea
Uvea | Vitreous & Retina | Optic Nerve & Brain | Oculosystemic Disease

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