Nailfold Capillaroscopy of Resting Peripheral Blood Flow in Exfoliation Glaucoma and Primary Open-Angle Glaucoma

Abstract

laucoma is a progressive neurodegenerative ocular disease that causes visual field loss owing to damage of the retinal ganglion cells. The most common type of glaucoma in the United States, primary open-angle glaucoma (POAG), 1 has been classified into normal-tension (NTG) and high-tension glaucoma (HTG) based on the cutoff point for the statistical reference range of intraocular pressure (IOP). 2 High-tension glaucoma is associated with various risk factors, such as older age, high IOP, African descent, and positive family history. 3 Exfoliation syndrome (XFS), an age-related systemic condition, is the most common recognizable cause of open-angle glaucoma worldwide, comprising most cases in some countries. 4 Exfoliation syndrome is characterized by the production, deposition, and progressive accumulation of a white fibrillogranular extracellular material (exfoliation material) throughout the anterior segment, most prominently on the anterior lens surface, on the zonules with their resultant weakness, and on the pupillary border. Exfoliation material is also found in posterior segment vessels, including the vortex veins, posterior ciliary arteries, and central retinal vessels. It is observed microscopically in numerous organs, including the skin, heart, lungs, and kidney, primarily in the connective tissue. 5-7 In addition to obstructing fluid pathways, exfoliation material accumulation affects vascular endothelial cells as well as contractile pericytes, which wrap IMPORTANCE Systemic blood flow alterations have been described using video nailfold capillaroscopy (NFC) in high-tension glaucoma (HTG) and normal-tension glaucoma (NTG) variants of primary open-angle glaucoma (POAG). To date, no previous studies have explored alterations in nailfold capillary blood flow in exfoliation glaucoma (XFG). OBJECTIVE To investigate the measure of peripheral blood flow as a surrogate marker of systemic vascular involvement in patients with XFG, HTG, and NTG, as well as in individuals serving as controls, using NFC.

The Relationship Between Nailfold Microcirculation and Retinal Microcirculation in Healthy Subjects

“…Pasquale et al (2015) have performed NFC on 199 patients with POAG and 124 controls and found dilated capillaries, hemorrhages, and avascular zone were associated with POAG after eliminated age, gender, and other confounding elements. Philip et al (2019) showed patients with exfoliation glaucoma and normaltension glaucoma presented lower resting peripheral capillary blood flow when compared with subjects without glaucoma.…”

“…Microvascular abnormalities are also recognized as important factors in ocular diseases, like retinal arterial occlusions, retinal vein occlusions glaucoma, non-arteritic anterior ischemic neuropathy, and glaucoma ( Flammer et al, 2001 ). Recently, some studies demonstrated nailfold microcirculation abnormalities were encountered in ocular diseases involved in vascular factors ( Pasquale et al, 2015 ; Chen et al, 2018 ; Philip et al, 2019 ). The development of optical coherence tomography angiography (OCTA) has revolutionized the resolution with which the retinal vasculature is visualized, allowing the potential to evaluate retinal microcirculation quantificationally.…”

Nailfold capillary morphology and platelet function in patients with exfoliative glaucoma

“…The limited range may also be associated with increased tortuosity in patients with XFS/XFG, as previously described by Cousins et al [25]. Philip et al [48] further argued that the pathophysiological mechanisms behind these flow alterations may be linked to the accumulation of exfoliation material in tissue, causing degenerative fibrillopathy in normal basement cell membranes. This degeneration may cause the aforementioned alterations in the peripheral vessels, including elastosis, oxidative stress, and vascular endothelial dysfunction, leading to vascular stiffness [9].…”

“…These authors found that nailfold capillary hemorrhages, avascular zones, and degree of microvascular tortuosity, as individually investigated features, had a greater association with XFS/XFG and POAG than with normal controls. While nailfold capillary morphology was the focus of the present study, Philip et al [48] recently investigated the peripheral nailfold blood flow circulation in XFG, concluding as we did that the vascular morphological and hemodynamic alterations in the peripheral nailfold circulation in XFG may serve as evidence of the systemic nature of exfoliation glaucoma. In their study, Philip et al examined not only patients with XFG, but also individuals diagnosed with normal-tension glaucoma (NTG).…”

Relationship between peripheral vasospasm and visual field progression rates in patients with normal-tension glaucoma with low-teen intraocular pressure

“…Therefore, indirect methods have been used to estimate the ocular blood flow from other peripheral vessels, such as patients' complaints about cold hand/feet, nailfold capillaroscopy, or laser Doppler flowmetry of the hand/feet. Previously, abnormal findings of nailfold capillaroscopy and laser Doppler flowmetry have been reported in NTG patients [13][14][15].…”