Low-Tension Glaucoma: An Oxymoron in Ophthalmology

Ciro Costagliola, MD; Luca Agnifili, MD, PhD; Leonardo Mastropasqua, MD; Alfonso di Costanzo, MD

Disclosures

Prev Chronic Dis. 2019;16(1):e10 

In This Article

Is the Optic Disc Appearance Secondary to Optic Nerve Hypoperfusion due to Vascular Diseases?

In patients with LTG and normal nychthemeral IOP curves, mechanical factors cannot be responsible for optic neuropathy; pressure-independent factors may be involved, with vascular alterations potentially being the most important.[5] A glaucomatous-like optic neuropathy may be observed in patients with history of a cardiovascular event or with chronic atherosclerosis or obstructive arterial diseases.[11] Reduced blood flow velocity in retrobulbar arteries and in cerebral circulation, low diastolic blood pressure, and smaller central retinal vessel diameter have been also observed in patients with LTG.[5] In these patients, the pathogenesis of disease is due to an impaired ocular perfusion pressure, mainly linked to primary vascular dysregulation or to a generalized dysfunction of the endothelial or autonomic nervous system.[5,11] However, it is unclear whether these factors were the cause or the result of the optic neuropathy. From a clinical point of view, LTG shows a higher incidence of disc hemorrhages and is more frequently associated with vascular diseases such as migraine, obstructive sleep apnea, or Raynaud's syndrome than with IOP.[5] Finally, about half of LTG patients with pre-perimetric disease show damage progression despite normal IOP values.[12] All these findings suggest the important role of vascular dysregulation.

In patients with cardiovascular diseases, optic disc cupping may tend not to progress if the underlying cause of the optic neuropathy has been controlled. Moreover, LTG patients may show circumpapillary atrophy as well as cerebral cortical microinfarcts, which are signs of ischemia.[5] In patients where vascular diseases induce a optic nerve hypoperfusion, a complete diagnostic examination for cardiovascular diseases must conducted, with the help of a cardiologist (Figure).

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