eMedicine Specialties > Ophthalmology > Cornea

Corneal Erosion, Recurrent

Author: Arun Verma, MD, Senior Consultant, Department of Ophthalmology, Dr Daljit Singh Eye Hospital, India
Coauthor(s): Michael P Ehrenhaus, MD, Director, Department of Cornea, External Disease & Refractive Surgery, Assistant Professor, Department of Ophthalmology, State University of New York Downstate Medical Center
Contributor Information and Disclosures

Updated: Jun 17, 2009

Introduction

Background

Recurrent corneal erosion (RCE) syndrome is a condition that is characterized by a disturbance at the level of the corneal epithelial basement membrane, resulting in defective adhesions and recurrent breakdowns of the epithelium.

Corneal erosions are perhaps one of the most common and neglected ocular disorders. Some of these cases occur after ocular trauma, but most of them occur spontaneously. Painful RCE syndrome, whether due to trauma or to anterior basement membrane dystrophy (Cogan dystrophy or map-dot-fingerprint dystrophy), results from abnormalities in the epithelial basement membrane.

Recurrent corneal erosions and epithelial basement membrane dystrophy are usually bilateral and are characterized by various patterns of dots, parallel lines that mimic fingerprints, and patterns that resemble maps, which appear in the epithelium. Individual microcysts may be oval, oblong, or comma-shaped and rarely appear alone but usually are associated with map and fingerprint patterns. On the other hand, the map and fingerprint patterns appear without dots or individual microcysts.

Map and fingerprint alterations of the corneal epithelium are not rare and can be found in asymptomatic individuals without prior history of trauma or ocular disease. Literature suggests that these epithelial changes are more common than previously recognized. They frequently are seen in conditions involving corneal edema, such as near a healing cataract surgery incision, or in the center of the cornea associated with Fuchs corneal dystrophy.

Clinical manifestations of Fuchs dystrophy

Three stages of Fuchs endothelial dystrophy are recognized. The 3 stages usually evolve gradually over a period of 25 years, and, like other corneal dystrophies, they usually are bilateral but asymmetric.

The first stage is the onset of cornea guttata, usually in the fourth decade of life. Subjective symptoms rarely occur until the fifth or sixth decade. During the asymptomatic phase, endothelial guttata and pigment dusting can be seen by slit lamp examination of the central corneal endothelium and by specular reflection. The guttate excrescences can become more numerous and confluent so that individual guttata are lost completely in the beaten-metal appearance of the endothelial surface. The central cornea is involved first, and, as the disease progresses, it spreads toward the periphery.

In the second phase of the disease, blurred vision, glare, and halos around lights develop because of incipient corneal edema in the stroma and epithelium. Epithelial edema can be seen as small droplets (bedewing) on retroillumination with the slit lamp. Epithelial microcysts coalesce to form bullae, which produce varying amounts of pain when they burst; hence, the name bullous keratopathy. Striae form in the Descemet membrane as the cornea thickens posteriorly due to stromal swelling. The arc of the Descemet membrane from limbus to limbus is shortened, causing wrinkles in the Descemet membrane called striae. The microcystic epithelial vesicles may break, causing foreign body sensations and severe pain with more extensive corneal epithelial disruption.

In the third stage, recurrent corneal erosions, microbial ulceration, and persistent pain may occur. Corneal sensitivity usually is reduced.

Pathophysiology

The 2 categories of corneal abrasions are as follows: superficial (those not involving the Bowman layer) and deep (those that penetrate the Bowman layer but do not rupture the Descemet membrane). Corneal abrasions may result from foreign bodies, contact lenses, chemicals, fingernails, hair brushes, tree branches, and dust.

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 2 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 makes the eye more prone to recurrent erosion.

Recurrent corneal erosions occur because there is a defect in the epithelial basement membrane and in hemidesmosomes formation, resulting in epithelial loss, microcysts, and bullae.

Recurrent corneal erosions occurring after injury or any corneal insult result because of improper or inadequate healing of the basement membrane, either because the basal epithelial cells fail to produce proper basement membrane complexes to attach to the Bowman layer and stroma or because of faulty basement membrane adherence.

A traumatic cause has a better eventual prognosis for full recovery than does the spontaneous form. In the case of spontaneous corneal erosions, the underlying disease process may be an epithelial basement membrane corneal dystrophy. Studies with the electron microscope have shown that during recurrent corneal erosion episodes, there is separation of the anchoring system at the level of the epithelial cell membrane or below the level of the anchoring plaques. Normal and degenerate polymorphonuclear leucocytes (PMNs) were found within and between the epithelial cells and within the anchoring layer. The degenerate PMNs may secrete metalloproteinases that cleave the Bowman layer below the anchoring system.

Frequency

United States

Recurrent corneal erosions are quite frequent in developing countries where lack of proper nutrition plays a significant role in the health of the cornea. Moreover, they are more frequent in patients with the predisposing factors and in those patients that have associated skin problems (see Causes).

Mortality/Morbidity

The tendency for epithelial basement membrane dystrophy, recurrent erosion, or both is probably hereditary, with variable penetrance. If corneal erosions are inherited, the pattern is dominant; however, most corneal erosions are acquired. In a study by Laibson, it has been found that 6% of the patients treated for a variety of other ocular conditions and diseases also demonstrated map, dot, and fingerprint changes in the epithelium.¹

A recurrent corneal erosion is most likely to develop in a person who has had a previous corneal abrasion that was very sharp, clean, and linear, like that from a paper cut. Because the cut is so sharp, without ragged edges, it is less likely to stick down tightly to the underlying basement membrane. Those who have an abnormal structure to the corneal epithelium (called map-dot-fingerprint dystrophy) are at a much greater risk of poor healing following a corneal abrasion and, thus, can develop a recurrent corneal erosion.

Just as it is nearly impossible to see a corneal abrasion with the naked eye, the same is true for a recurrent corneal erosion. The time course is most important. In a recurrent corneal erosion, the patient can remember having had a corneal abrasion relatively recently (usually within the past 3–10 d) and then most often when first opening the eye in the morning.

Sex

Recurrent corneal erosions usually are seen as a bilateral problem occurring somewhat more frequently in females than in males. The epithelium may show a slipped-rug appearance; filaments are often seen. The recurrent erosions may occur over multiple sites on the cornea, a situation different from traumatic erosions.

Age

Recurrent corneal erosions and epithelial basement membrane dystrophy occur in adults, usually after the fourth decade of life. However, there are studies that have associated recurrent corneal erosions with juvenile Alport syndrome, which is an X-linked condition that also presents with anterior lenticonus and retinal flecks, as well as renal complications. Certain anterior corneal dystrophies, such as Reis-Bücklers, and lattice dystrophies can cause painful recurrent erosions in children.

Clinical

History

For all patients who present with signs and symptoms of RCE syndrome, a careful history and examination of the cornea should be undertaken to ensure that no underlying factors have predisposed these patients to this condition. This applies even in those cases where a history of injury to the cornea is present because a defect in the epithelial basement membrane complex may have been present before the initial trauma.

Of patients with anterior basement membrane dystrophy, 80-90% are asymptomatic. The primary symptom of recurrent erosion syndrome is mild to severe eye pain. Symptoms, when they occur, consist of one or more of the following:

• Slightly blurred vision (when the epithelial and basement changes are in the visual axis)
• Visual acuity loss
• Astigmatism
• Epithelial blebs
• Foreign body sensation with recurrent erosion, when the epithelium loosens  
  • This is commonly the first symptom of recurrent erosion, and, in some cases, patients who have previously experienced this pain on awakening are so fearful of the pain that they are unable to sleep well.
  • The pain is fleeting in most cases, lasting only for a few seconds, but it may last from minutes to 1-2 hours and is a warning that the epithelium has not healed.
  • Attacks of pain and ocular irritation occurring in the early morning hours or upon awakening are understandable because corneal hydration from lid closure may be a factor affecting epithelial adhesion. An abnormal adherence between lid and cornea may be a factor in setting the stage for an attack of epithelial erosion.
  • Sudden sharp pain often is felt in the early morning during sleep or on awakening when a frank epithelial defect occurs because of the eyelid movement across the loosened epithelium.
• Recurrences affect the area of the cornea that was previously injured.

Physical

Depending on the severity of the erosion, corneal examination findings may be totally normal, or they may reveal telltale signs of RCE syndrome. A classic history of recurrent pain upon awakening is often more important than seeing classic signs of corneal irregularity in making the correct diagnosis of RCE syndrome.

• During an acute attack, one may see epithelial loss, epithelial microcysts, bullae, lack of adherence of sheets of epithelium, and epithelial filament formation. In these instances, the visual acuity may be impaired severely if the pathogenic condition occurs in the pupillary area. The examination findings may be totally normal, or there may be barely visible epithelial irregularities (may have negative staining) where the erosion has almost completely resolved.
• An external eye examination generally shows a corneal abrasion, often centrally located that stains brightly with fluorescein. The abraded area tends to create loose edges with moderate-to-large epithelial flaps, which commonly form. A brownish granular edema (brawny edema) may occupy the underlying anterior stroma. The tendency toward a central location and dense secondary edema can cause a significant deterioration in vision.
• Recurrent corneal erosions can be classified as either microform or macroform. With the latter, severe pain persists from hours to days as a result of a large area of the epithelium being separated from the cornea. In posttraumatic cases, the microform type of erosion always occurs at the site of the original abrasion. Microform recurrent erosions are characterized by intraepithelial microcysts with a minor break in the epithelium. These erosions are usually associated with brief episodes of pain, lasting from seconds to minutes.
• Laibson et al have stated that in the interval between attacks, one can detect epithelial cysts, surface irregularity, and some subepithelial scarring on slit lamp examination.¹ The healed epithelial area may even resemble a dendritic figure, a pseudodendrite. This fact should be kept in mind to avoid prescribing unnecessary medication.

Causes

Most cases of recurrent erosions are related to anterior basement membrane dystrophy or are caused by corneal injuries from fingernails and paper. Acquired recurrent erosions also are observed after the following:

• Alkali burns
• Foreign bodies
• Post infectious ulcers from herpes simplex
• Exposure
• Cockayne syndrome
• Reis-Bücklers dystrophy
• Vitrectomy
• Photocoagulation
• Secondary to other corneal dystrophies (eg, lattice, Fuchs, other anterior membrane dystrophies)
• Contact lenses  
  • Soft contact lenses have many uses and are made from a variety of materials. The most common pitfall in the matter of lens care is the inability to keep lenses clean of deposits. These deposits can consist of protein, lipid, or calcium. They can cause discomfort, pseudomyopia, loss of vision, displacement of lenses (usually in an upward direction), and corneal erosions.
  • Unfortunately, thimerosal (sodium ethylmercurithiosalicylate) is the major offender in producing a delayed hypersensitivity response. It causes recurrent corneal erosions, conjunctival hyperemia, or corneal deposits. Many thimerosal-free solutions are now being prepared.
  • Drying of the lenses can result in a change in lens curvature, which alters the fit and can cause conjunctival irritation and swelling or corneal epithelial erosions. Conjunctival swelling results in tightening of the lens, which can cause pain, corneal edema, and epithelial erosions.
  • A flat-fitting contact lens moves too much and is uncomfortable to wear. Such a lens can give rise to central corneal epithelial edema and erosions. If the lens is too tight, the eye becomes uncomfortable, there is circumcorneal injection, and there may be epithelial erosions.
  • Postoperative management of corneal transplants for severely alkali-burned corneas includes the protection of the epithelium with well-fitted bandage contact lenses. But if the lenses are not of proper fit, they can lead to recurrent corneal erosions.
  • Recurrent corneal erosion is an indication for the use of a therapeutic lens. However, with the advent of anterior stromal puncture and related procedures, many clinicians choose to definitively treat typical posttraumatic recurrent corneal erosions, thereby minimizing the number of such patients requiring therapeutic lenses. Bandage lens treatment, if used for this indication, must be continued for up to 8-26 weeks to facilitate repair of the corneal epithelial basement membrane.
• Patients with junctional epidermolysis bullosa, one of the rarest types, have more corneal problems (eg, recurrent corneal erosions) but relatively little conjunctival involvement. 
  • In the acquired autoimmune form, the immune response is believed to be directed against the basement membrane proteins uncein and collagen VII. It may be associated with small subepithelial vesicles in the cornea, symblepharon, and scarring of the lacrimal puncta.
  • Topical neomycin produces contact hypersensitivity in 5-10% of patients. Eyelid edema, conjunctivitis, and punctate corneal erosions may be due to allergic and toxic effects of topical neomycin.
  • While the corneal epithelium is affected minimally by a low dose of topical neomycin, cytotoxicity occurs at concentrations greater than 5 mg/mL. Corneal sensation can be altered with very high levels of neomycin eye drops.
• The effects of topical paromomycin on the ocular surface have not been studied adequately. Frequent dosing and prolonged administration presumably can slow wound healing and may contribute to conjunctival hyperemia and punctate corneal erosions.
• Topical diamidines can produce stinging and burning immediately after application. Conjunctival hyperemia and punctate corneal erosions have been attributed to its use.
• Mast cell degranulation with histamine release is produced by propamidine. Contact hypersensitivity has been described.
• While some corneal epithelial damage occurs with all topical anesthetics, it is most exaggerated when cocaine is used, with epithelial loosening and corneal erosions. This may be an advantage when removing epithelium in the treatment of a dendritic ulcer.
  • Toxic effects on epithelial cell metabolism and ultrastructure include depressed cellular respiration and glycolysis with lactic acid accumulation; alterations in desmosomes, intracellular mitochondria, rough endoplasmic reticulum, and tonofibrils; and inhibition of cell mitosis and migration.
  • Epithelial microvilli loss results in instability and rapid breakup of the tear film. Thus, local anesthetics may retard healing of corneal erosions as epithelial cells round up and accumulate at the wound margin. The epithelium may totally lift off the basement membrane proteins and cell membrane permeability; destruction of mitochondria, rough endoplasmic reticulum, and tonofibrils; and inhibition of cell mitosis and migration.

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