131 ORIGINAL ARTICLE Eur J Ophthalmol ( 2010 ; : 1 ) 131-135 20 © 2010 Wichtig Editore - 1120-6721 INTRODUCTION Normotensive glaucoma (NTG) is a primary open-angle glaucoma (POAG) variety that features glaucomatous visu- al field changes and progressive optic nerve damage de- spite intraocular pressure (IOP) within the normal range (1). The precise mechanisms of disease remain incompletely understood. Progressive optic neuropathy despite a nor- mal IOP suggests vascular dysregulation and accelerated apoptosis under glutamate toxicity (2). Intracellular calcium influx seems to be a critical point in both vascular dysregu- lation and accelerated apoptosis (3, 4). Magnesium is the physiologic calcium blocker of nature and has been shown to lower baseline vascular tension and ef- fects of vasoconstrictors, and to increase peripheral blood flow and coronary blood flow in coronary spasm (5-10). It also inhibits vasospasm in subarachnoid hemorrhages (11). These effects have been attributed to a calcium antagonistic mecha- nism, possibly through the inhibition of calcium influx across the vascular smooth muscle cell membranes (12). In addition, magnesium can prevent glutamate toxicity by blocking NMDA receptors, hence protecting the cells against oxidative stress and apoptosis (13, 14). As a natural element and a physiologic calcium canal blocker, magnesium therapy has gained atten- tion and interest of glaucoma specialists in treatment of NTG. In this study, we aimed to evaluate the effect of oral magne- sium therapy on ocular blood flow and visual field parameters in patients with NTG. The effect of oral magnesium therapy on visual field and ocular blood flow in normotensive glaucoma Bahri Aydin 1 , Merih Önol 2 , Ahmet Hondur 3 , Mehmet Kaya 4 , Hakan Özdemir 2 , Atiye Cengel 2 , Berati Hasanreisoglu 2 1 Ophthalmology Department, Faculty of Medicine, Fatih University 2 Faculty of Medicine, Gazi University 3 Ophthalmology Department, TDV 29 Mayis Hospital 4 Cardiology Department, Faculty of Medicine, Erciyes University, Kayseri - Turkey PURPOSE. To evaluate the effect of oral magnesium therapy on ocular blood flow and visual field perim- etry indices in patients with normotensive glaucoma (NTG). METHODS. Fifteen patients with NTG (study group) received 300 mg oral magnesium citrate for 1 month, while 15 patients with NTG (control group) received no treatment. Blood magnesium level measure- ment, visual field analysis, and color Doppler imaging of the orbital vessels were done before treat- ment and at 1 month. RESULTS. In the study group, mean deviation improved from -3.7±1.9 (mean ± standard deviation) at baseline to -2.5±1.8 at 1 month (p<0.05), and pattern standard deviation improved from 3.6±2.3 at baseline to 2.8±2.6 at 1 month (p<0.05). Color Doppler imaging indices did not change after magne- sium therapy. CONCLUSIONS. Oral magnesium therapy may provide improvement in the visual field, but does not seem to affect ocular blood flow in patients with NTG. Other mechanism than increased ocular blood flow may be responsible for the improvement in the visual field with oral magnesium therapy. (Eur J Oph- thalmol 2010; 20: 131-5) KEY WORDS. Magnesium, Normotensive glaucoma, Ocular blood flow, Visual field Accepted: June 17, 2009