Effect of Topical Glaucoma Therapy on Tear Film Stability in Healthy Subjects

Long term treatment with anti-glaucomatous drugs has been shown to increase the incidence of dry eye syndrome with all known consequences such as ocular discomfort and epithelial keratitis. Given that thinning of the tear film appears to be a risk factor for the development or the aggravation of dry eye syndrome, the current study seeks to investigate whether tear film thickness is changed after topical treatment with anti-glaucomatous drugs in healthy subjects. For this purpose, tear film thickness will be measured at baseline and after single instillation of one of 5 study drugs in one randomly chosen eye. In addition, one group of 20 subjects will receive no drug and will serve as a second control. Drug effects on tear film thickness will be compared to the fellow, non-treated eye. In addition, effects on tear film thickness of timolol with preservatives (Timoptic 0.5%) will be compared to timolol without preservatives (Timophtal sine 0.5%) and three lubricants with different viscosity (Genteal HA, Hylo-Comod, Thealoz).