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II. DEGENERATIVE DISEASES OF THE CONJUNCTIVA

PINGUECULA

Pingueculae are extremely common in adults. They appear as yellow nodules on both sides of the cornea (more commonly on the nasal side) in the area of the palpebral aperture. The nodules, consisting of hyaline and yellow elastic tissue, rarely increase in size, but inflammation is common. In general, no treatment is required, but in certain cases of pingueculitis, weak topical steroids (eg, prednisolone 0.12%) or topical nonsteroidal anti-inflammatory medications may be given (Figure 5-21).

PTERYGIUM

A pterygium is a fleshy, triangular encroachment of a pinguecula onto the cornea, usually on the nasal side bilaterally (Figure 5-22). It is thought to be an irritative phenomenon due to ultraviolet light, drying, and windy environments, since it is common in persons who spend much of their lives out of doors in sunny, dusty, or sandy, windblown surroundings. The pathologic findings in the conjunctiva are the same as those of pinguecula. In the cornea, there is replacement of Bowman's layer by hyaline and elastic tissue.

If the pterygium is enlarging and encroaches on the pupillary area, it should be removed surgically along with a small portion of superficial clear cornea beyond the area of encroachment. Beta-irradiation, topical mitomycin C, and conjunctival autografting have all been used to reduce the risk of recurrent disease.

CLIMATIC DROPLET KERATOPATHY (BIETTI'S BAND-SHAPED NODULAR DYSTROPHY, LABRADOR KERATOPATHY, SPHEROIDAL DEGENERATION)

Climatic droplet keratopathy is an uncommon degenerative disorder of the cornea characterized by aggregates of yellowish-golden spherules that accumulate in the subepithelial layers. The cause is unknown, but certain factors such as exposure to ultraviolet light, aridity, and microtrauma are recognized predisposing factors. The deposits may result in elevation of the epithelium in a band-shaped configuration. The condition is more common in geographic regions with high levels of direct and reflected sunlight.

10.1036/1535-8860.ch5

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