EFFECTS OF OPHTHALMIC VEHICLES ON THE STABILITY OF THE PRECORNEAL FILM

Abstract

The break up time (BUT) of the precorneal film was studied before and after application of 34 different vehicles. The material examined comprised 646 [human] eyes. Maximum increase of the BUT was obtained with 2% methyl cellulose (4 times) and 10% polyvinyl alcohol (7 times). These vehicles in the usually empolyed concentrations, fat-free ointment (polyethylene glycol), acetylcysteine and polysaccharide (dextran) affected a less pronounced prolongation. The BUT was reduced 4 or 5 times by fatty, anhydrous ointments and by silicone oil, about 2 or 3 times by emulsions and oils and twice by 0.01% benzalkonium chloride. The clinical significance of the BUT alterations was discussed.