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Abstract

Purpose: To evaluate the effects of felodipine, a calcium channelblocker, on ocular circulation. Methods: In a double blind, randomized,crossover design, 10 volunteers received placebo or felodipine on 2 separatedays. Bidirectional laser Doppler velocimetry (BLDV), laser Doppler flowmetry(LDF), and monochromatic fundus photography (MFP) were employed to assessretinal, choroidal, and optic nerve rim circulatory parameters. Measurements wereobtained at baseline, 1.5, and 3 hours after dosing. Blood pressure, intraocularpressure (IOP), and heart rate were monitored, and perfusion pressure (PP) wascalculated. Results: In comparison to placebo, significant average percentagedecreases in diastolic blood pressure (BPd; p = 0.001), mean blood pressure (BPm;p = 0.003), and perfusion pressure (PP; p = 0.003) were observed 1.5 hours following felodipine. No significant differences were observed following placebo. Retinal, choroidal and optic nerve rim circulatory parameters showed no significant changes after placebo or felodipine. A significant positive correlation between BPd and optic nerve velocity (ONvel) was observed 3 hours following felodipine (R = +0.654; p = 0.040). In contrast, no significant correlation between BPd and ONvel was noted (R = +0.198; p = 0.583) following placebo. Conclusions: No significant change in retinal, optic nerve rim, or foveolar choroidal blood flow were observed, a factor that may be important in the treatment of systemic hypertension in patients with glaucoma.
Abbreviations:BLDV – Bidirectional laser Doppler velocimetry;BPd – diastolic blood pressure;BPm – mean blood pressure;BPs – systolic blood pressure;CHflow – choroidal flow;CHvel – choroidal velocity;CHvol – choroidal volume;D – vessel diameter;LDF – Laser Doppler flowmetry;MFP – monochromatic fundus photography;ONflow – optic nerve flow;ONvel – optic nerve velocity;ONvol – optic nerve volume;PP – perfusion pressure;Q – retinal volumetric blood flow rate;Vmax – maximum velocity of whole blood;Vmean – mean velocity of whole blood.

calcium channel blockers - choroidal circulation - felodipine - laser Doppler flowmetry - optic nerve rim circulation - retinal circulation

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