Pattern of ocular response to topical and systemic prostaglandin

Changes in both intraocular pressure and total outflow facility were determined after short- and long-term infusion and topical application of prostaglandin E1 and E2. The intraocular pressure with both routes of administration increased within 15 minutes by 10 to 15 mm. Hg; long-term infusion caused the intraocular pressure to be elevated for a longer time, although a fall in intraocualr pressure occurred despite continued infusion. Total outflow facility did not increase until 30 minutes after initiation of treatment and thereafter increased further with time, irrespective of the route of drug application. The initial increase in intraocular pressure is suggested to be the result of vascular changes, namely an increase in the leakiness of the iris vessels and the capillary pressure of the ciliary body vessels caused by the vasodilatory actions of prostaglandins.