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Normal-Tension Glaucoma Causes

Although its cause is not completely understood, normal-tension glaucoma is generally believed to occur either because of an unusually fragile optic nerve that can be damaged despite a normal pressure inside the eye or because of reduced blood flow to the optic nerve.

• Unusually fragile optic nerves may be inherited.
  
  
• Reduced blood flow to the optic nerve can be due to disorders of the blood vessels (called vascular diseases), including vasospasms and ischemia.
  
  
  • Vasospasms are spasms or constrictions of the blood vessels.
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  • Ischemia is reduced oxygen delivered to the tissue, in this case the optic nerve, because the blood vessels are either narrowed or obstructed.