Ocular blood flow was determined using radioactive strontium 85 microspheres after an alkali (sodium hydroxide [NaOH]) burn to the eye. With 20 microL of NaOH, blood flow was significantly increased in the iris, ciliary processes, and choroid from two through four hours. This correlated well with the sustained increase in intraocular pressure (IOP) seen after a 20-microL burn. A 50-microL burn increased blood flow at one hour, but it returned toward normal levels beyond two hours. In general terms, there appeared to be a meaningful correlation between IOP changes and altered blood flow following ocular alkali burns. The blood flow changes paralleled those occurring after the topical application of prostaglandins and supported the concept that ocular blood flow dynamics are mediated by prostaglandins.