Blood flow in glaucoma.
OBJECTIVE
Glaucoma, one of the leading causes of blindness in the world, is characterized by progressive visual field loss and distinctive excavation of the optic nerve head. Although elevated intraocular pressure is the major risk factor, there is increasing evidence that the pathogenesis of glaucoma is also linked to altered ocular blood flow. This review summarizes the recent publications relevant to blood flow in glaucoma.


RESULTS
Several studies indicate that a perfusion instability, rather than a steady reduction of ocular blood flow, might contribute to glaucomatous optic neuropathy. The main cause of the instability is a disturbed autoregulation in the context of a general vascular dysregulation. The underlying mechanism of such a vascular dysregulation is not known. A dysfunction of both the autonomic nervous system and vascular endothelial cells is discussed.


CONCLUSIONS
The mechanical and vascular theories are not mutually exclusive; on the contrary, a vascular dysregulation increases the susceptibility to intraocular pressure. Therapeutically, therefore, both an intraocular pressure reduction and an improvement of the ocular blood flow might be considered.
Grieshaber
Matthias C
MC
University Eye Clinic Basel, Switzerland.
Flammer
Josef
J
D000818:Animals; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D019332:Endothelin-1 / Q000097:blood; D005123:Eye / Q000098:blood supply*; D005902:Glaucoma, Open-Angle / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D017078:Laser-Doppler Flowmetry; D009880:Ophthalmic Artery / Q000502:physiology*; D009901:Optic Nerve Diseases / Q000209:etiology / Q000503:physiopathology; D012039:Regional Blood Flow / Q000502:physiology; D018615:Ultrasonography, Doppler, Color; D014661:Vasoconstriction / Q000502:physiology; D014794:Visual Fields / Q000502:physiology
D015415:Biomarkers; D019332:Endothelin-1