Excerpt from Corneal Erosion, Recurrent

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RCE syndrome may occur secondary to corneal injury or spontaneously. In the latter case, some predisposing factor, such as diabetes or a corneal dystrophy, may be the underlying cause. Management of RCE syndrome is usually aimed at regenerating or repairing the epithelial basement membrane to restore the adhesion between the epithelium and the anterior stroma.

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.

Manifestation

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 membrane) and deep (those that penetrate the Bowman membrane but do not rupture the Desceme .....

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