TABLE 5-8 ■ Opacities of the Cornea and Lens
A corneal arcus is a thin grayish white arc or circle not quite at the edge of the cornea. It accompanies normal aging but may also be seen in younger people, especially African Americans. In young people, a corneal arcus suggests the possibility of hyperlipoproteinemia but does not prove it. Some surveys have revealed no relationship.
A corneal scar is a superficial grayish white opacity in the cornea, secondary to an old injury or to inflammation. Size and shape are variable. It should not be confused with the opaque lens of a cataract, visible on a deeper plane and only through the pupil.
A pterygium is a triangular thickening of the bulbar conjunctiva that grows slowly across the outer surface of the cornea, usually from the nasal side. Reddening may occur intermittently. A pterygium may interfere with vision as it encroaches upon the pupil.
Cross Section of Lens
Capsule A cataract is an opacity of the lens and is seen through the pupil. Cataracts are classified in many ways, including cause and location. Old age is the most common cause. Two kinds of age-related \ cataract are illustrated below. In each
Cortical example, the pupil has been widely cataract dilated.
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