Chapter 6: Cornea
CORNEAL PIGMENTATION
Pigmentation of the cornea may occur with or without ocular or systemic disease. There are several distinct varieties.
Krukenberg's Spindle
In this disorder, brown uveal pigment is deposited bilaterally upon the central endothelial surface in a vertical spindle-shaped fashion. It occurs in a small percentage of people over age 20, usually in myopic women. It can be seen grossly but is best observed with the slitlamp. The visual acuity is only slightly affected, and the progression is extremely slow. Pigmentary glaucoma must be ruled out by yearly intraocular pressure measurements.
Blood Staining
This disorder occurs occasionally as a complication of traumatic hyphema with secondary glaucoma and is due to hemosiderin in the corneal stroma. The cornea is golden brown, and vision is decreased. In most cases the cornea gradually clears in 1-2 years.
Kayser-Fleischer Ring
This is a pigmented ring whose color varies widely from ruby red to bright green, blue, yellow, or brown. The ring is 1-3 mm is diameter and located just inside the limbus posteriorly. In exceptional cases there is a second ring. The pigment is composed of fine granules immediately below the endothelium. It involves Descemet's membrane, rarely the stroma. Electron microscopic studies suggest that the pigment is a copper compound. The intensity of the pigmentation can be reduced markedly by the use of chelating agents.
These rings, which were long considered to be pathognomonic of hepatolenticular degeneration (Wilson's disease), have recently been described in three nonwilsonian patients with chronic hepatobiliary disease and in one patient with chronic cholestatic jaundice. Recognition of the Kayser-Fleischer rings, however, remains important, since such notice calls attention to the possibility that the patient has Wilson's disease. Specific medical treatment with the copper chelating agent penicillamine may dramatically improve a disease that would otherwise inevitably be fatal.
Iron Lines (Hudson-StŠhli Line, Fleischer's Ring, Stocker's Line, Ferry's Line)
Localized deposits of iron within the corneal epithelium may occur in sufficient quantity to become visible clinically. The Hudson-StŠhli line is a horizontal line at the junction of the middle and lower thirds of the cornea, corresponding to the line of lid closure, in otherwise normal elderly patients. Fleischer's ring surrounds the base of the cone in keratoconus. Stocker's line is a vertical line associated with pterygia, and Ferry's line develops adjacent to limbal filtering blebs. Similar iron deposits are seen at the site of corneal scars.
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10.1036/1535-8860.ch6