الفهرس 
Introduction and aim of workOnly 14 pages are availabe for public view
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Abstract
The aim of this study is to examine the nitric oxide , endothelin-1 and zinc levels ( as a first part ) in aqueous humor in patients with POAG , comparing them with the levels in control patients. Since NO acts locally and has a short half life measurement of the No radical itself is difficult, so the stable end product nitrite is the parameter measured as a marker of NO. Researchers have found increased NO levels in POAG and this may be attributed to the activity of NOS-2 in advanced cases of POAG where in these cases there is optic nerve damage due to raised NO levels. Others found reduced NO levels and this is the cause of raised IOP and this may be of significance as low levels may lead to the inappropriate vasodilatory effect and hence reducation of the IOP lowering effect. Endothelin-1 levels are examined by directly measuring the protein level in aqueous humor. It was found that endothelin-1 levels are raised in POAG patients and also in low tension glaucoma associated with vasospastic disorders in some patients.