Changes in optic nerve head blood flow and retrobular hemodynamics following calcium-channel blocker treatment of normal-tension glaucoma.
BACKGROUND
Because calcium channel blockers reduce vascular resistance, they may have a clinical application in the treatment of normal-tension glaucoma (NTG). This study investigates changes in both the optic disc blood flow and the hemodynamics of retrobulbar vessels in NTG patients after the systemic administration of a calcium channel blocker.


METHODS
Twelve eyes of 12 NTG patients (mean age 57.6 +/- 15.3 years) were examined before and after a 4-week treatment with 2 mg b.i.d. oral nilvadipine, an L-typc calcium channel blocker. By scanning laser-Doppler flowmetry (SLDF), we obtained the velocity, flow, and volume from within a 10 x 10 pixel window placed on the temporal rim region of the optic disc perfusion map. By ultrasound color Doppler imaging (CDI), we measured the peak systolic velocity (PSV) and the end diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), nasal posterior ciliary artery (NPCA), and temporal posterior ciliary artery (TPCA). We then calculated a resistance index (RI) for each vessel.


RESULTS
After treatment, the flow and velocity of the optic disc blood flow significantly increased (P < 0.05). Nilvadipine also significantly reduced RIs of the CRA, NPCA, and TPCA (P < 0.05), and increased both the PSV of the NPCA and the EDVs of the CRA, NPCA, and TPCA. The percent change in velocity correlated significantly with the percent changes of the CRA RI and NPCA RI.


CONCLUSIONS
Oral nilvadipine appears to reduce orbital vascular resistance, which consequently increases the optic disc blood flow.
Tomita
G
G
Department of Ophthalmology, Gifu University School of Medicine, Gifu-ken, Japan. gtom-gifC@umin.u-tokyo.ac.jp
Niwa
Y
Y
Shinohara
H
H
Hayashi
N
N
Yamamoto
T
T
Kitazawa
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D002908:Chronic Disease; D019842:Ciliary Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009898:Optic Disk / Q000098:blood supply*; D009915:Orbit / Q000098:blood supply*; D011379:Prognosis; D011446:Prospective Studies; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance / Q000187:drug effects
D002121:Calcium Channel Blockers; C035100:nilvadipine; D009543:Nifedipine