Acetylsalicylic acid does not reduce the intraocular pressure variation inocular hypertension or glaucoma

The purpose of this study was to measure if intraocular pressure (IOP) and IOP variations in patients with ocular hypertension and glaucoma are decrea sed by acetylsalicylic acid (ASA). The hypothesis to be tested was that sho rt-term fluctuations in the IOP are caused by breaks of the inner wall of S chlemm's canal that are repaired by platelets inducing a cycle of breaks an d repair. Furthermore, prostaglandins affect uveoscleral outflow and ASA in hibits prostaglandin biosynthesis and platelet aggregation. This implies th at ASA may have complex effects on the IOP and its variations. In 28 patients with ocular hypertension or glaucoma the IOP was measured se ven times during 2 hr on two succeeding days. Five hundred mg ASA or placeb o was administrated orally in a masked fashion 15 hr prior to the second se ssion. After wash-out, this procedure was repeated with a cross-over design . The same study outline was used in 28 glaucoma patients except for the cr oss-over design. There were no statistically significant differences in the mean IOP or in t he IOP variations between the placebo treated and the ASA treated eyes in e ither group, and there were no significant differences between the day befo re and after treatment in any group. The results suggest that ASA does not affect IOP variations in a clinically significant way and that a single dos e of ASA has no significant effect on mean IOP. (C) 2000 Academic Press.