Fig. 22. Furrow degeneration associated with systemic disease. Light microscopy of a 47-year-old woman with Sjögren's syndrome who developed a perforated marginal corneal ulcer shows the healed appearance of iris incorporated into a fibrous scar whose central margin is steeper than its gently sloping peripheral margin (periodic acid-Schiff, × 32). (Green WR: Histopathology of furrow degeneration. Arch Ophthalmol 90:470, 1973. Copyright 1973, American Medical Association)