Effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size.
OBJECTIVE
To evaluate the effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size under scotopic and photopic luminance conditions in persons considering laser refractive surgery.


METHODS
Ophthalmic Health Center, Tel Aviv, Israel.


METHODS
The pupil size was measured in 36 eyes of 36 participants under scotopic and photopic conditions using the Colvard pupillometer (Oasis Medical) before and after brimonidine tartrate drops were administered. The pupil size was subsequently measured after 30 minutes and 4 and 6 hours.


RESULTS
No difference was found in pupil size before brimonidine tartrate instillation in eyes with light or dark irides. Before instillation, the mean photopic pupil size was 4.81 mm +/- 0.54 (SD) (range 4.0 to 6.0 mm). At 30 minutes, all pupils became miotic, with a mean size of 3.77 +/- 0.51 mm (range 3.0 to 5.0 mm) (P<.0001). After 6 hours, 27.8% of the pupils had returned to their previous size. Before brimonidine tartrate administration, the mean scotopic pupil size was 6.22 +/- 0.73 mm (range 5.0 to 8.0 mm). There was significant miosis to 4.57 +/- 0.84 mm (range 3.0 to 6.5 mm) (P<.0001) that continued for at least 6 hours. The miotic effect of brimonidine tartrate was stronger in eyes with light irides.


CONCLUSIONS
Brimonidine tartrate caused significant miosis, especially under scotopic conditions, most likely from its alpha-2 adrenergic effect. Under photopic luminance conditions, the miotic effect was pronounced.
Kesler
Anat
A
Department of Ophthalmology, Tel Aviv Medical Center, 6 Weizmann Street, Tel Aviv 64239, Israel. kesler@netvision.net.il
Shemesh
Gabi
G
Rothkoff
Levi
L
Lazar
Moshe
M
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000068438:Brimonidine Tartrate; D003623:Dark Adaptation; D005127:Eye Color / Q000187:drug effects; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000494:pharmacology; D011680:Pupil / Q000187:drug effects*; D011810:Quinoxalines / Q000008:administration & dosage / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D000068438:Brimonidine Tartrate