Purpose: To evaluate the effect of new antiglaucomatous medications on the precorneal tear film.
Methods: 18 healthy subjects (33y) received in a double masked, cross over design topical dorzolamide, brimonidine and latanoprost eye drops, and as a control balanced saline solution. At baseline measurement of break up time (BUT) and the Schirmer test (ST) were performed. 60 min after baseline measurements the topical medication was applied. The measurements were repeated 30 min, 60 min and 90 min after administration.
Results: The ST decreased in brimonidine treated subjects (n=18) after 30 min by 29%, after 60min by 13% and after 90min by 26%. The corresponding reductions in the latanoprost group were 17%/17%/34% and in the dorzolamide group 2%/14%/27%. All these changes proved not be statistically significant. BUT increased in brimonidine treated subjects by 7%/13% and decreased after 90 min by 16%. The changes in the dorzolamide group were +10%/±0%/-20%. In the latanoprost group there was found a highly statistically significant drop of BUT by 27% (60min) and by 56% (90min) (p<0.01).
Conclusions: Whereas the BUT changes in the dorzolamide and brimonidine group were moderate, the drop in BUT in latanoprost treated subjects was highly significant. This effect might be due to the high concentration of preservatives in this ophthalmic solution. NONE 1University Eye Clinic Hamburg, Germany 2University Eye Clinic San Diego, U.S.