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Editors Selection IGR 13-4

Blood Flow: Nilvadipine in NTG

Josef Flammer

Comment by Josef Flammer on:

22359 A placebo-controlled 3-year study of a calcium blocker on visual field and ocular circulation in glaucoma with low-normal pressure, Koseki N; Araie M; Tomidokoro A et al., Ophthalmology, 2008; 115: 2049-2057


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"IOP lowering treatment is the only proven therapy for glaucoma", is what we hear over and over again in glaucoma meetings. The study by Koseki et al. (1643) nicely demonstrates that there are indeed other therapeutic modalities beside IOP reduction, particularly in NTG-patients. The discussion about the role of calcium channel blockers (CCB) is an old one. Some authors are afraid of a negative inotropic effect and in particular that treatment with CCB's could further reduce blood pressure. This study confirms that a low dose of CCB, in this case of Nilvadipine, does not reduce blood pressure further and significantly improves ocular perfusion.There is also an old debate as to whether improvement of ocular circulation is of clinical relevance.

There may be other therapeutic modalities beside IOP reduction, particularly in NTG patients
In the present study, progression of visual field was less in the treated group. The authors, therefore, hypothesized whether this might be due to an improved blood circulation or whether this could be due to a direct effect of CCB's on the neural tissue. Theoretically, both hypotheses are possible. If we consider other studies, however, we observe similar short- term effects on visual fields of patients treated with CCB's, carbonic anhydrase inhibitors or even after carbon dioxide (CO2) breathing. Pillunat, showed several years ago, that patient's with improved visual fields during CO2 breathing, were also those who responded well over the long term to calcium-channel blockers with their visual fields. One likely reason for these observations is the improved ocular blood flow leading to improved visual fields. In our experience, not all patients profit from treatment with CCB's. Patients with a vascular dysregulation syndrome, on the average, responded more favorably than others. The authors correctly point out that the drug may have other effects besides blocking calcium channels. In addition, the potent antioxidative effect is of particular interest. We like to remind the reader of the fact that some beta blockers, namely, have both calcium channel blocking activity and antioxidant effects.



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