Acute versus chronic effects of brimonidine on aqueous humor dynamics in human eyes

Carol B Toris, C. B. Camras, M. E. Yablonski, V. S. Garden

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Abstract

Purpose. The acute versus chronic effects of brimonidine, a selective α2-adrenergic agonist, on aqueous humor dynamics was determined in 27 ocular hypertensive patients. Methods. Aqueous flow (Fa, μL/min) and outflow facility (Cfl, ML/min/mmHg) were determined with fluorophotometry. Intraocular pressure (IOP, mmHg), tonographic outflow facility (C-, pL/ min /mmHg), and episcleral venous pressure (Pev, mmHg) were measured. Uveoscleral outflow (Fu, -L/min) was calculated from IOP, Fa, Pev and CE1 values. All measurements were made on baseline day, day 8, and day 29 of twice daily application of brimonidine (0.2%) to one eye and its vehicle to the other in a randomized, double-masked fashion. IOP and Fa were measured after one drop on day 1. Résulta. Reported are means of IOP, Fa and Fu ( p<0.05, within group analysis of changes from baseline, paired ttest; t p<0.05, comparing overall mean changes between treated and control eyes, repeated measures ANOVA). CONTROL EVE TREATED EVE lOPt 20.3 17.9 18.5 18.5 20.5 14.2 14.9 15.9 Fat 2.6 2.2 2.5 2.3 2.4 1.6 1.9 2.1 Fu 0.45 0.58 0.77 0.65 1.07 1.09 Pev, Cf1, and Cton, were not signif icant ly changed. Conclusion. Brimonidine reduces IOP in humans initially by decreasing Fa and later partially by increasing Fu.

Original languageEnglish (US)
Pages (from-to)S243
JournalInvestigative Ophthalmology and Visual Science
Volume38
Issue number4
Publication statusPublished - Dec 1 1997

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ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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