[Practical assessment. Clinical evaluation of normal-tension glaucoma]

Normal-tension glaucoma is a form of primary open-angle glaucoma where the intraocular pressure remains within the normal range. The progression of the disease is usually very slow. The main challenge is to establish the correct diagnosis, with a double risk: the patient might have undetected (and untreated) high intraocular pressure or, the patient might have a nonglaucomatous (possibly treatable) disease looking as a glaucomatous optic neuropathy. The clinical evaluation of the patient suspected of a normal-tension glaucoma must answer two questions: 1) is the intraocular pressure normal?, 2) is it a glaucomatous optic neuropathy or another type of optic neuropathy?