Urea has been widely accepted as an osmotic ocular hypotensive agent.1-5 Given intravenously at 1 gm. per kilogram, it rapidly reduces intraocular pressure. Consequently, it has proved dramatically effective in acute angle-closure glaucoma.6 However, it has been suggested that urea not be used as a last resort in this disorder, since results are not as impressive in the highly inflamed eye.6 This has been attributed to loss of the normal osmotic gradient which exists between blood urea nitrogen and aqueous urea nitrogen. If this gradient is reduced or destroyed, only a small osmotic effect is to be expected.
This communication reports a study to evaluate the ocular hypotensive potential of urea before and after alteration of the blood aqueous barrier by anterior segment inflammation.
Material and Methods
Albino rabbits weighing 2-3 kg. were utilized. In 1 group of animals, a polyethylene catheter was inserted into the marginal
GALIN MA, DAVIDSON R. Hypotensive Effect of Urea in Inflamed and Noninflamed Eye. Arch Ophthalmol. 1962;68(5):633–635. doi:10.1001/archopht.1962.00960030637011