Single-dose nimodipine normalizes impaired retinal circulation in normal tension glaucoma.
OBJECTIVE
Several studies indicate that calcium channel blockers improve the clinical course of normal tension glaucoma (NTG), whereas the underlying mechanism is not fully investigated. Hemodynamic improvement and neuroprotective effects are discussed. In this study, we measured the hemodynamic effects of nimodipine on retinal circulation.


METHODS
Sixteen patients with NTG and clinical signs of vasospastic hyperreactivity, such as suffering from extremely cold hands and feet, were consecutively selected out of the local glaucoma registry. Ten healthy age-matched volunteers were included as controls. Retinal capillary blood flow was measured by Scanning Laser Doppler Flowmetry in both eyes before and 90 +/- 10 minutes after a single oral dose of 30 mg nimodipine.


RESULTS
Before administration of nimodipine, retinal capillary blood flow was significantly reduced in NTG patients compared with controls (262 +/- 80 vs. 487 +/- 164 AU, P < 0.001). Nimodipine increased retinal capillary blood flow in NTG patients by 91 +/- 73% (P < 0.001) to values of healthy controls (440 +/- 113 vs. 439 +/- 123 AU, P = 0.635). In controls, nimodipine did not show significant effects.


CONCLUSIONS
In NTG patients with additional vasospastic symptoms, retinal capillary blood is significantly reduced in comparison with healthy controls. Single-dose nimodipine yields to a normalization of retinal circulation in NTG patients up to values of healthy controls 90 minutes after drug administration.
Michalk
Fabian
F
Medical Clinic (Cardiology, Angiology), Friedrich-Alexander-University Erlangen-Nuremberg.
Michelson
Georg
G
Harazny
Joanna
J
Werner
Ulrike
U
Daniel
Werner G
WG
Werner
Dierk
D
D001775:Blood Circulation; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009553:Nimodipine / Q000008:administration & dosage*; D009898:Optic Disk / Q000098:blood supply; D012039:Regional Blood Flow / Q000187:drug effects; D012164:Retinal Diseases / Q000188:drug therapy* / Q000503:physiopathology; D012171:Retinal Vessels / Q000187:drug effects* / Q000503:physiopathology; D014664:Vasodilation / Q000187:drug effects
D002121:Calcium Channel Blockers; D009553:Nimodipine