الفهرس | Only 14 pages are availabe for public view |
Abstract Results : The term ?normal tension glaucoma? refers to typical glaucomatous optic disc cupping and VF loss in eyes that have normal IOP, open angles, and the absence of any contributing ocular or specific systemic disorders. This disease is often called ?lowtension glaucoma,? which is a misnomer because the IOP is usually at the upper end of the normal range and rarely low. Great controversy surrounds the pathogenesis of normal tension glaucoma. Some authorities believe that normal tension glaucoma is a variant of primary open angle glaucoma in which the optic discs demonstrate greater susceptibility to the effects of IOP. As a rule, normal tension glaucoma is seen in older individuals, especially those over age 60 although it is possible to see rare cases in those under the age of 50. The disease appears to occur more often in women than in men. A relatively high prevalence of normal tension glaucoma is present in the Japanese population. When the disease is suspected a careful history to exclude previous phases of increased IOP, an internal medicine checkup including 24hour blood pressure measurements and neurological assessment are required A proper assessment of patients including a diurnal (24hours) IOP evaluation, gonioscopy, standard static computerized visual field testing, and assessment of optic nerve head and retinal nerve fiber layer are essential steps in diagnosis. Treatment is similar to that for chronic open angle glaucoma and is aimed at lowering IOP. Most clinicians believe that lowering IOP is the main thrust of treatment of progressive normal tension glaucoma. Conclusion : Normal tension glaucoma is a multifactorial disease. When it is suspected a careful history to exclude previous phases of increased IOP, and neurological assessment are required .A proper assessment of patients including IOP evaluation, gonioscopy, standard static computerized visual field testing, and assessment of optic nerve head and retinal nerve fiber layer are essential steps in diagnosis. A significant reduction in IOP (30% from the highest IOP reading) has been shown to benefit the course of the disease in about 80 % of cases. Avoid nonselective beta blockers and epinephrine drugs because of potential vasoconstrictive properties. Calcium channel blockers and other neuroprotective have the potential to increase optic nerve perfusion and may one day become aviable treatment for normal tension glaucoma. |