Two glaucomatous patients had a clinical picture of atypical band kera
topathy develop several years after local antiglaucoma treatment, incl
uding pilocarpine, tiloptic, and epinephrine. These medications consis
ted of three preservatives: benzalkonium chloride, edetate disodium te
tra acetate (EDTA), and boric acid. The combination of benzalkonium ch
loride and EDTA was reported to cause a toxic effect on superficial st
romal keratocytes. It is assumed that this atypical band keratopathy h
as developed in a primarily degenerated superficial stroma, which is a
ssociated with the toxic effect of this combination of three preservat
ives.