The ability of intravenous urea to lower intraocular pressure has been well demonstrated.1 Though some authors considered a diuretic mechanism for its action, rather convincing evidence has been brought forth indicating the effect is due to the osmotic gradient established.2-5 It is known that this substance is maintained at a higher concentration in blood than in aqueous.6 However, it has not been determined what happens to this normal gradient at high blood levels of urea. It is the purpose of this communication to present the blood and aqueous urea levels following the intravenous administration of that substance to humans.
Materials and Methods
Patients hospitalized for routine cataract extraction were the subjects of this study. On the day of testing, venous blood was obtained for subsequent analysis of blood and plasma nitrogen. Shortly thereafter a 30% solution of lyophilized, ammonia-free urea* dissolved in 10% invert sugar was administered