The effect of daily use of brimonidine tartrate on the dark-adapted pupil diameter.
OBJECTIVE
To investigate the effect of daily brimonidine tartrate 0.15% on the dark-adapted pupil diameter.


METHODS
Observational case series.


METHODS
Ten normal volunteers administered brimonidine to their right eyes once daily. Four to six hours later, infrared pupil photographs were taken after dark adaptation. Measurements were performed at baseline; on treatment days 1, 5, 11, and 18; and on washout days 1 and 2.


RESULTS
One subject had no response. The nine responding subjects showed an average maximum antimydriatic effect of -1.63 mm (range, -0.57 mm--2.30 mm); all subjects experienced tachyphylaxis. Five subjects showed rebound mydriasis (mean maximum rebound +0.87 mm larger than baseline; range 0.50 mm-1.22 mm). The untreated pupil also responded, showing antimydriasis (two subjects), rebound mydriasis (two subjects), or paradoxical direct mydriasis (one subject).


CONCLUSIONS
Once-daily use of brimonidine tartrate to prevent dark-induced pupil dilation can lead to tachyphylaxis and rebound mydriasis.
Brown
Sandra M
SM
Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, 3601 Fourth Street, Lubbock, TX 79430-7217, USA. Sandra.brown@ttuhsc.edu
Khanani
Arshad M
AM
McCartney
David L
DL
D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D000068438:Brimonidine Tartrate; D003623:Dark Adaptation / Q000187:drug effects*; D006801:Humans; D015878:Mydriasis / Q000209:etiology; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D011680:Pupil / Q000187:drug effects*; D011810:Quinoxalines / Q000008:administration & dosage*; D012008:Recurrence; D013618:Tachyphylaxis
D000316:Adrenergic alpha-Agonists; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D000068438:Brimonidine Tartrate