Resting nailfold capillary blood flow in primary open-angle glaucoma.

Area of Science:

• Ophthalmology
• Cardiovascular Physiology
• Microcirculation Research

Background:

• Primary open-angle glaucoma (POAG) is associated with altered hemodynamics in ocular capillaries.
• Abnormal non-ocular blood flow may also contribute to POAG.
• Nailfold capillaries offer an accessible window into microvascular function, unaffected by intraocular pressure (IOP).

Purpose of the Study:

• To investigate the relationship between resting nailfold capillary blood flow and primary open-angle glaucoma (POAG).
• To determine if reduced nailfold capillary blood flow is an independent factor in POAG.
• To assess the influence of IOP and beta-blocker use on this relationship.

Main Methods:

• Video capillaroscopy was used to measure resting nailfold capillary blood flow in 67 POAG patients and 63 controls.
• Blood flow was quantified by tracking blood column voids, measuring vessel diameter, and calculating flow rates.
• Multiple logistic regression analysis was employed to assess the association between nailfold blood flow and POAG, with adjustments for covariates.

Main Results:

• POAG cases exhibited significantly lower mean nailfold capillary blood flow (26.8±17.6 pL/s) compared to controls (50.1±24.2 pL/s) (p<0.0001).
• Each pL/s increase in resting nailfold blood flow was associated with a 6% reduction in the odds of POAG (p<0.0001), independent of blood pressure, pulse, and IOP.
• Similar associations were observed in subgroups stratified by maximum IOP and topical beta-blocker use.

Conclusions:

• Reduced resting nailfold capillary blood flow is a characteristic finding in primary open-angle glaucoma (POAG).
• This microcirculatory alteration is present independently of other clinical factors like blood pressure, pulse, and intraocular pressure (IOP).
• Nailfold capillaroscopy may serve as a valuable tool for assessing systemic vascular contributions to POAG.