title: Timolol increased retrobulbar flow velocities in untreated glaucoma eyes but not in ocular hypertension.
abstract: OBJECTIVE
  To investigate retrobulbar blood flow velocities and the effects of topical timolol treatment in eyes with newly detected, previously untreated open angle glaucoma or ocular hypertension.
  
  
  METHODS
  Fifteen eyes with open angle glaucoma (OAG) and 12 eyes with ocular hypertension (OH), in the same number of patients, all untreated and newly detected, were examined with colour Doppler imaging of retrobulbar vessels before and after 1 month of topical timolol treatment (0.5% Timoptic BID).
  
  
  RESULTS
  Baseline central retinal artery end diastolic velocity was lower (48%, p=0.0002) and resistive index higher (7.6%, p=0.018) in the OAG group than in the OH group. In the glaucoma group mean end diastolic velocity increased by 41%, (p=0.006) while resistive index decreased by 5.8%, (p=0.02) on treatment, while no significant changes were seen in the OH group. Blood flow velocities in the ophthalmic artery did not change with treatment. Baseline IOP and IOP reduction did not differ between OAG and OH group.
  
  
  CONCLUSIONS
  Peripheral resistance to blood flow was found to be increased in untreated glaucoma eyes as compared to a similar group of eyes with ocular hypertension. Timolol treatment diminished resistance significantly in the glaucoma group, but not in the ocular hypertension group. Thus the two groups responded differently to timolol treatment. The reaction to IOP lowering treatment could indicate defective autoregulation in the glaucoma group.
authors.affiliation: Department of Ophthalmology, Malmö University Hospital, Malmö, Sweden. ingar.c-bergstrand@oftal.mas.lu.se
authors.forename: I C
authors.initials: IC
authors.lastname: Bergstrand
authors.forename: A
authors.initials: A
authors.lastname: Heijl
authors.forename: P
authors.initials: P
authors.lastname: Wollmer
authors.forename: F
authors.initials: F
authors.lastname: Hansen
authors.forename: A
authors.initials: A
authors.lastname: Harris
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy / Q000503:physiopathology*; D006706:Homeostasis; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy / Q000503:physiopathology; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009883:Ophthalmic Solutions; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013999:Timolol / Q000627:therapeutic use*; D018615:Ultrasonography, Doppler, Color
chemical_list: D000319:Adrenergic beta-Antagonists; D009883:Ophthalmic Solutions; D013999:Timolol