Normal-tension glaucoma: a contemporary perspective on the problem

Normal-tension glaucoma (NTG) is one of the most difficult forms of glaucoma to diagnose, as intraocular pressure remains within the normal range and diffuse retinal light sensitivity does not change until the advanced stages of the disease. Timely diagnosis of NTG requires careful assessment of risk factors for disease development. One of the most significant risk factors is heredity. The majority of NTG cases have a complex genetic basis caused by the combined effects of multiple genes, although efforts to identify specific gene mutations characteristic of this form of glaucoma are ongoing. Vascular pathology represents a major risk factor for NTG development. Peripheral vasospasm, cerebral atherosclerosis, alterations in blood rheological properties, endothelial dysfunction, systemic hypertension or hypotension contribute to the progression of glaucomatous optic neuropathy. Nocturnal arterial hypotension is a particularly important factor in NTG pathogenesis. NTG is frequently associated with Flammer syndrome, Raynaud syndrome, and migraine. Significant changes in NTG are detected in the superficial vascular plexus of the macular region of the retina, which may indicate a key role of the vascular factor in the development of this disease. NTG is a multifactorial, genetically determined disorder, and careful assessment of risk factors for its development and progression is required for timely diagnosis.