Retrobulbar arterial hemodynamic effects of betaxolol and timolol in normal-tension glaucoma.
Publication/Presentation Date
8-1-1995
Abstract
PURPOSE: beta-Adrenergic blocking drugs lower intraocular pressure. The question of whether these drugs also alter, either directly or indirectly, orbital hemodynamics is potentially of great importance for patients with normal-tension glaucoma who may have some degree of reversible vasospasm.
METHODS: We compared the effect of selective (betaxolol) and nonselective (timolol) beta-adrenergic blocking drugs on flow velocities (as determined by color Doppler imaging) in orbital vessels in 13 patients with normal-tension glaucoma (mean age, 62 +/- 3 years; mean intraocular pressure, 15 +/- 2 mm Hg). A one-month drug treatment double-masked crossover design, with a three-week washout before each drug, was used.
RESULTS: Neither drug changed peak systolic velocity in any of the four vessels studied (ophthalmic, nasal and temporal posterior ciliary, and central retinal arteries). Additionally, timolol did not alter end-diastolic velocity or resistance index (defined as [peak systolic velocity minus end-diastolic velocity] divided by peak systolic velocity) in any of the vessels measured. In contrast, betaxolol tended to increase end-diastolic velocity and to decrease resistance index: the four-vessel average end-diastolic velocity increased 30% (P = .08), and the four-vessel average resistance index decreased significantly (P = .04). These reductions in resistance index occurred despite that betaxolol, in contrast to timolol, did not significantly decrease intraocular pressure.
CONCLUSIONS: These results suggest that, in patients with normal-tension glaucoma, selective beta-adrenergic blockade (betaxolol) may have ocular vasorelaxant effects independent of any influence on intraocular pressure, whereas nonselective blockade (timolol) lowers intraocular pressure without apparently altering orbital hemodynamics.
Volume
120
Issue
2
First Page
168
Last Page
175
ISSN
0002-9394
Published In/Presented At
Harris, A., Spaeth, G. L., Sergott, R. C., Katz, L. J., Cantor, L. B., & Martin, B. J. (1995). Retrobulbar arterial hemodynamic effects of betaxolol and timolol in normal-tension glaucoma. American journal of ophthalmology, 120(2), 168–175. https://doi.org/10.1016/s0002-9394(14)72604-2
Disciplines
Business Administration, Management, and Operations | Health and Medical Administration | Management Sciences and Quantitative Methods
PubMedID
7639300
Department(s)
Administration and Leadership
Document Type
Article