Effects of brimonidine on aqueous humor dynamics in human eyes.
Arch Ophthalmol
; 113(12): 1514-7, 1995 Dec.
Article
in En
| MEDLINE
| ID: mdl-7487618
ABSTRACT
OBJECTIVE:
To evaluate the mechanism by which brimonidine, a selective alpha 2-adrenergic agonist, lowers intraocular pressure (IOP) in humans.SUBJECTS:
Twenty-one volunteers with ocular hypertension.METHODS:
Brimonidine tartrate (0.2%) was given topically twice daily for 1 week to one eye in a randomized, double-masked study. The fellow eye was similarly treated with brimonidine vehicle. Before (baseline) and after 1 week (day 8) of dosing, IOP, aqueous flow, episcleral venous pressure, and tonographic outflow facility were directly measured. Fluorophotometric outflow facility and uveoscleral outflow were calculated. Brimonidine-treated eyes were compared with vehicle-treated contralateral control eyes and with baseline measurements after 1 week of dosing.RESULTS:
Brimonidine significantly (P < .001, Student's two-tailed t test) reduced IOP mean +/- SE of 4.7 +/- 0.7 and 4.2 +/- 0.4 mm Hg compared with the baseline day and with the vehicle-treated contralateral control eyes, respectively. Compared with the baseline day, aqueous flow was reduced by 20% (P = .002) and uveoscleral outflow was increased (P = .04). A slight contralateral decrease in IOP of 1.2 +/- 0.6 mm Hg (P = .05) and in aqueous flow of 12% (P = .05) was noted. No significant difference was seen in the outflow facility values or episcleral venous pressure compared with the baseline day or with the contralateral control eye.CONCLUSIONS:
The brimonidine-induced reduction in IOP in humans is associated with a decrease in aqueous flow and an increase in uveoscleral outflow. The decrease in IOP and aqueous flow in the contralateral control eye on day 8 compared with the baseline day suggests a mild contralateral effect.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Aqueous Humor
/
Quinoxalines
/
Ocular Hypertension
/
Adrenergic alpha-Agonists
/
Antihypertensive Agents
Type of study:
Clinical_trials
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Arch Ophthalmol
Year:
1995
Document type:
Article
Affiliation country:
United States