Purpose:
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.
Patients and 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.
