Normal tension glaucoma about four times as high as the prevalence of the "classical glaucoma" with an IOP of 22 mm Hg and higher. The pillar of the current understanding of normal tension glaucoma is a reduced IOP tolerance of the retinal ganglion cells and the cells in the optic nerve head - an IOP of, for example, 17 or 19 mm Hg that would not affect a healthy eye leads to damage in the eye of an NTG patient. In many patients, normal tension glaucoma is common in individuals with a generalized reduced perfusion of organs and certain body tissues. A low
Glaucoma valve drainage, such as iStent, CyPass, or Hydrus. A Cochrane Review of various aqueous shunts and modifications found that the Baerveldt implant may result in lower IOP than the Ahmed implant, but it was unclear if the difference in IOP reduction was clinically significant. The review suggests that practitioners should operate with the devices that they are most comfortable with, and have the most experience using. The glaucoma valve implant is indicated for glaucoma patients not responding to maximal medical therapy, with previous failed guarded filtering surgery (trabeculectomy) or in cases where conventional drainage surgery is unlikely to succeed. Common situations