THE AMERICAN burdock (Arctium minus; cocklebur), during the late summer and fall months, can be found in all of the 48 states. This common weed, often growing to the height of a man's shoulder, bears a profusion of hooklet-covered burs (Fig. 1). Enclosed within each bur are literally hundreds of extremely fine, sharply pointed, barbed bracts, or phyllaries (Fig. 2). Although finer than the average adult human hair, these bracts are very rigid and firm, easily capable of penetrating the conjunctiva, and even the tarsal plate. The unidirectional orientation of the barbs forces the burdock bract, once embedded, to burrow even deeper into the ocular tissues.
This minute bract is a particularly painful ocular foreign body. Its presence is characterized by severe ocular discomfort, foreign body sensation, photophobia, marked conjunctival hyperemia, stringy mucoid, or even pseudomembranous, conjunctival exudation, lid edema, blepharospasm, and pathognomonic abrasions of the corneal epithelium. Small granulomatous
HAVENER WH, FALLS HF, McREYNOLDS WU. BURDOCK BUR OPHTHALMIA. AMA Arch Ophthalmol. 1955;53(2):260-263. doi:10.1001/archopht.1955.00930010262013