The Immediate Response in Applanation Pressure to Intravenous Acetazolamide in Primary Glaucomas and Glaucoma Suspects

Abstract

The decays in the applanation pressures of both eyes, after a reduction of the aqueous secretion by means of intravenous acetazolamide, are studied with respect to shape and steepness by comparison with reference curves calculated from different values of the facility of aqueous outflow. The pressure decays in three out of four eyes with narrow-angle glaucoma exhibited "breaks" possibly resulting from a stepwise reopening of the chamber angle during the decompression. Twenty patients with intraocular hypertension and open angles could be divided into two groups according to the facility of aqueous outflow (in mul mmHg-1 min-1), estimated from approximately matching reference curves: Nine patients with facilities above 0.15 had normal visual fields and nearly indentical pressure curves of the two eyes. Out of 11 patients with facilities below 0.15, seven patients had glaucomatous visual field defects and excavated optic discs. The pressure curves of eye pairs in this low facility group showed asymmetry, and breaks were seen in approximately half of the curves. These might be caused by changes in the outflow facility due to a decompression of collapsed outflow channels. However, the morphological basis for such an interpretation is not as well founded as in the case of narrow-angle glaucoma.

Intravenous hypertonic saline to reduce intraocular pressure

“…After intravenous administration, the peak occurs 30–60 min after injection (Nissen 1975). The median absolute reduction at 5 and 15 min after intravenous acetazolamide, estimated from the graphs published, was 4 mmHg (range, 0–6) and 8 mmHg (5–12 mmHg), respectively (Nissen 1975). Thus, acetazolamide provides its peak effect slower than IVHTS.…”

“…We did not observe any serious side effects, but such can occur after the administration of hypertonic saline and one should be aware of them when lowering IOP with IVHTS. When hyponatraemia is corrected rapidly, osmotic demyelination syndrome (ODS), also known as central pontine myelinolysis may occur, with destruction of myelinated nerve fibres (Nissen 1975; Tyagi et al. 2007).…”