To measure aqueous dynamic variables in patients with open-angle glaucoma when their ocular hypotensive treatment was withdrawn and to determine if the circadian rhythm of the aqueous humor flow was present in open-angle glaucoma.
We studied 20 patients with open-angle glaucoma, and a group of 20 healthy subjects served as controls. Aqueous humor flow was measured by clearance of topically applied fluorescein with a fluorophotometer, tonography was used to measure outflow facility, and applanation tonometry was used to measure the intraocular pressure.
We did not find any statistically significant difference when comparing aqueous flow during the daytime in subjects with open-angle glaucoma with that in controls. However, we did measure a higher aqueous flow at night in the group with open-angle glaucoma, compared with the normal group. The circadian rhythm of aqueous humor flow was present in the subjects with glaucoma.
Aqueous flow is not suppressed in glaucomatous eyes that are not undergoing treatment. Rather, the flow is slightly higher at night during sleep compared with the flow in normal sleeping subjects, but not high enough to have a clinically significant effect on intraocular pressure.
Larsson L, Rettig ES, Brubaker RF. Aqueous Flow in Open-angle Glaucoma. Arch Ophthalmol. 1995;113(3):283-286. doi:10.1001/archopht.1995.01100030037018