title: Effects of D-timolol and L-timolol on ocular blood flow and intraocular pressure.
abstract: Effects of D-timolol and L-timolol on IOP were compared with two rabbit models. When the drug solution was injected into vortex vein, 1% D-timolol produced ocular hypotension just like 0.5% L-timolol except D-timolol was less potent than L-timolol to lower the IOP. On the other hand, when 0.5% of D-timolol and L-timolol were instilled into the rabbit eye on IOP recovery model both agents showed equipotency to delayed the IOP recovery. Effects of D-timolol and L-timolol on ocular blood flow were also studied with two rabbit models. D-Timolol at 0.5% did not affect the ocular pulsatile blood flow measured with Langham's pneumatonometer whereas 0.5% L-timolol significantly suppressed it. D-Timolol (0.5%) was found to increase retinal and choroidal blood flows measured with laser Doppler method whereas L-timolol suppressed it. These results indicate that D-timolol though less potent than L-timolol to lower IOP, is superior over L-timolol to improve the blood flow in retina and choroid.
authors.affiliation: Institute of Ocular Pharmacology, Texas A&M University College of Medicine, College Station.
authors.forename: G C
authors.initials: GC
authors.lastname: Chiou
authors.forename: F
authors.initials: F
authors.lastname: Zhao
authors.forename: Z F
authors.initials: ZF
authors.lastname: Shen
authors.forename: B H
authors.initials: BH
authors.lastname: Li
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002829:Choroid / Q000098:blood supply; D005123:Eye / Q000098:blood supply*; D005260:Female; D007275:Injections, Intravenous; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D012171:Retinal Vessels / Q000187:drug effects; D013237:Stereoisomerism; D013999:Timolol / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D013999:Timolol