Anatomical Considerations
Staining Patterns

Deposited mucus not cleaned from the back of the lens or scratches on the back of the lens can cause discomfort and scratch-like stains on the cornea as illustrated in figure A to the right. ��

Figure B shows a fatigue stain which has a dull, hazy appearance. Subtle folds or wrinkles can accompany it. This condition is most frequently observed in long-term contact lens wear. Other possible causes are a large lens, flat lens, unmoving lens or high riding lens.

 

The arc stain shown in figure C is crescent-shaped, and is most often superficial. It can possibly be caused a poorly designed hard contact lens edge, insufficient peripheral and intermediate posterior curves, dried mucus near the edge, a scratched edge, or peripheral or intermediate posterior curves, a poorly centered soft lens with a wrinkled edge. Correction of this problem usually requires modification in lens design or fit.

Figure D represents a re-centering stain which is arc shapedand linear caused by the edge of a hard contact lens. It can be one or several unbroken stains that to not recur unless the lens continues to get displaced. Other possible causes are a flat lens, and too much and too flat a peripheral posterior curve.