THE EFFECT OF PRESERVATIVES AND ANTIGLAUCOMATOUS MEDICATION ON THE HISTOPATHOLOGY OF THE CONJUNCTIVA

Background: Topical medication applied chronically for the treatment o f glaucoma changes the cellular profile of the conjunctiva. We wanted to determine the role of preservatives, which are usually combined wit h the drugs, on this effect Methods: We applied metipranolol 0.3 % and pilocarpine 2 % with and without benzalkonium chloride 0.01 % and cet rimonium chloride 0.004 %, respectively. Twenty-four rabbits, divided into four groups, were treated for 3 months. The complete globes and t he adherent bulbar conjunctiva were examined histopathologically and i mmunohistochemically Results: With special stains for collagen, a slig ht increase of the thickness of subepithelial collagen of the conjunct iva was present in both groups treated with medication and preservativ e compared with eyes treated with medication alone. This effect was al so true for special antibodies for collagen type IV and alpha-smooth m uscle actin in the eyes treated with pilocarpine, but not in the eyes treated with metipranolol Conclusion: The results suggest that preserv atives may have an additional adverse effect on the conjunctiva in add ition to the effects of the medications alone.