Effects of Lomerizine, a Calcium Channel Antagonist, on Retinal and Optic Nerve Head Circulation in Rabbits and Humans

Abstract

Lomerizine increases blood velocity, and probably blood flow, in the ONH and retina in rabbits, and it also increases blood velocity in the ONH in healthy humans, without significantly altering blood pressure or heart rate.

Use of laser speckle flowgraphy in ocular blood flow research

“…1999). Thirdly, the NB value shows good correlation with tissue blood flow rate determined with the microsphere method in the retina, choroid and iris ( r = 0.59, p < 0.001; r = 0.60, p < 0.001; r = 0.61, p = 0.0002, respectively), and with blood flow rate determined with the hydrogen gas clearance method in the ONH ( r = 0.92, p < 0.01) in rabbit eyes (Tamaki et al. 1994, 1995, 1996a, 2003; Sugiyama et al.…”

“…Although no direct comparison between SBR values and results obtained by the coloured microspheres technique or hydrogen gas clearance method in the same site of an eye has been published, SBR values obtained in vitro (Fujii et al. 1996) and in vivo (Nagahara et al. 2003, unpublished results) were very well correlated with NB values obtained in vitro and in vivo , respectively.…”

“…However, for this reason, the values obtained with this technology should not be used to compare velocity between fellow eyes, different eyes or different sites in one eye. By contrast, these values are suited to monitor the time–course of change in the tissue blood velocity at the same site in the same eye at various intervals ranging from seconds to months (Tamaki et al. 1996a, 1996b, 1999a, 2003; Tomidokoro et al.…”

Effect of Flunarizine, a Calcium Channel Blocker, on Intraocular Pressure and Aqueous Humor Dynamics in Monkeys

“…7-10 However, when administered systemically, calcium antagonists have shown variable effectiveness in lowering IOP, with the majority of studies showing no effect on IOP. 25,26 In studies of the effect of oral calcium antagonists on ocular blood flow or visual fields in normotensive patients, nimodipine, 27 lomerizine, 28 and flunarizine 29 had no effect on IOP. In patients with glaucoma who were treated with nimodipine, nifedipine, diltiazem, or verapamil, there was no additional lowering of IOP despite improvement in hemodynamic or visual field parameters.…”

“…18 Calcium antagonists have also been reported to be neuroprotective in ischemia-reperfusion models in vivo 34,35 and in excitotoxicity models in which retinal ganglion cells and cortical neurons in cell culture were exposed to N-methyl-D-aspartate and glutamate 3,35 or in which nerve growth factor was withdrawn. 20 In addition, the effect of this class of agents on vascular smooth muscle could contribute to the improvement in optic nerve head or retinal blood flow measured in normal subjects and in patients with glaucoma after treatment with calcium channel blockers, 9,15,16,28 and to the improvement in visual field parameters observed in patients with normal tension glaucoma. [11][12][13]16 These experimental results indicate that calcium channel blockers may both reduce IOP and provide some degree of neuroprotection in glaucoma.…”