A marked fall in nocturnal blood pressure is associated with the stage of primary open-angle glaucoma in patients with arterial hypertension

Changes in choroidal thickness and lamina cribrosa position in subjects with overdipper pattern of arterial pressure

IntroductionThe purpose is to analyze the changes produced in subjects with an overdipper pattern of ambulatory blood pressure monitoring with the aim of understanding the pathophysiology of normal tension glaucoma.MethodsA cross sectional study was performed in patients exhibiting overdipper and non-overdipper blood pressure patterns, respectively. Different optic parameters were assessed including the analysis of ganglion cell layer (GCL), peripapillary retinal nerve fiber layer (pRNFL) and Bruch's membrane opening-minimum rim width (BMO-MRW), as well as changes produced in choroidal thickness (CT) and lamina cribrosa (LC) position at two different periods of the day (early morning and evening).ResultsA total of 80 eyes (42 overdipper and 38 non-overdipper) were analyzed. A shortening of the distance at the beginning and end of the LC was objectified in the overdipper subjects (p < 0.003) as well as a statistically significant shift of the LC between morning and evening measurements in the overdipper subjects (p < 0.023). In addition, a significant thickening was found in 13 measurements of the horizontal and vertical plane CT (p < 0.029) of the overdipper subjects and a thickening of the CT in both groups in the morning. No significant differences in pRNFL, BMO-MRW and GCL measures were objectified.ConclusionsMorning assessment in overdipper subjects showed a deeper LC and a LC shift in comparison to evening values. In addition, an increase in CT was found in these subjects. Altogether, these findings could illustrate an etiopathogenic mechanism of the damage produced in normal tension glaucoma associated to the overdipper pattern.

The Role of Axonal Transport in Glaucoma

Glaucoma is a neurodegenerative disease that affects the retinal ganglion cells (RGCs) and leads to progressive vision loss. The first pathological signs can be seen at the optic nerve head (ONH), the structure where RGC axons leave the retina to compose the optic nerve. Besides damage of the axonal cytoskeleton, axonal transport deficits at the ONH have been described as an important feature of glaucoma. Axonal transport is essential for proper neuronal function, including transport of organelles, synaptic components, vesicles, and neurotrophic factors. Impairment of axonal transport has been related to several neurodegenerative conditions. Studies on axonal transport in glaucoma include analysis in different animal models and in humans, and indicate that its failure happens mainly in the ONH and early in disease progression, preceding axonal and somal degeneration. Thus, a better understanding of the role of axonal transport in glaucoma is not only pivotal to decipher disease mechanisms but could also enable early therapies that might prevent irreversible neuronal damage at an early time point. In this review we present the current evidence of axonal transport impairment in glaucomatous neurodegeneration and summarize the methods employed to evaluate transport in this disease.

Association of Nailfold Capillary Abnormalities With Primary Open-angle Glaucoma and Glaucomatous Visual Field Loss

PRECIS

Nailfold capillary abnormalities are associated with primary open-angle glaucoma (POAG) and increased severity of global and central glaucomatous visual field (VF) loss.

PURPOSE

The purpose of this study was to investigate whether nailfold capillary abnormalities are associated with POAG and the severity of glaucomatous VF loss.

MATERIALS AND METHODS

A cross-sectional study of 83 POAG cases and 40 controls was conducted. Nailfold capillaroscopy images were assessed by masked graders for dilated capillaries >50 μm, crossed capillaries, tortuous capillaries, hemorrhages, avascular zones >100 μm, capillary density, and capillary distribution. VF loss in glaucoma cases was quantified using mean deviation and mean central pattern standard deviation (PSD) from the worst-affected eye.

RESULTS

Logistic regression analyses of cases and controls showed that avascular zones [odds ratio (OR)=1.24; 95% confidence interval (CI): 1.06, 1.47; P=0.005], capillary density (OR=0.63; 95% CI: 0.46, 0.83; P<0.001), and capillary distribution (OR=7.88; 95% 95% CI: 2.53, 28.40; P=0.001) were associated with POAG. Simple linear regression analysis of cases only showed that nailfold hemorrhages were associated with mean deviation (β=-5.10; 95% CI: -9.20, -1.01; P=0.015) and mean central PSD (β=-4.37; 95% CI: -8.18, -0.57; P=0.025), and this remained significant in the multiple linear regressions. After controlling for demographic and clinical factors, avascular zones were associated with both mean deviation (β=-0.76; 95% CI: -1.48, -0.04; P=0.040) and mean central PSD (β=-0.78; 95% CI: -1.45, -0.10; P=0.024), whereas capillary distribution was only associated with mean deviation (β=-4.67; 95% CI: -7.92, -1.43; P=0.017).

CONCLUSION

Nailfold capillary abnormalities are associated with POAG as well as increased global and central vision loss.

Primary Open Angle Glaucoma and Vascular Risk Factors: A Review of Population Based Studies from 1990 to 2019

Glaucoma is one of the leading causes of blindness worldwide, and as the proportion of those over age 40 increases, so will the prevalence of glaucoma. The pathogenesis of primary open angle glaucoma (POAG) is unclear and multiple ocular risk factors have been proposed, including intraocular pressure, ocular perfusion pressure, ocular blood flow, myopia, central corneal thickness, and optic disc hemorrhages. The purpose of this review was to analyze the association between systemic vascular risk factors (including hypertension, diabetes, age, and migraine) and POAG, based on major epidemiological studies. Reports presenting the association between POAG and systemic vascular risk factors included a total of over 50,000 patients. Several epidemiological studies confirmed the importance of vascular risk factors, particularly hypertension and blood pressure dipping, in the pathogenesis and progression of glaucomatous optic neuropathy. We found that diabetes mellitus is associated with elevated intraocular pressure, but has no clear association with POAG. No significant correlation between migraine and POAG was found, however, the definition of migraine varied between studies.

Ocular blood flow as a clinical observation: Value, limitations and data analysis

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.

Machine Learning-Based Predictive Modeling of Surgical Intervention in Glaucoma Using Systemic Data From Electronic Health Records

PURPOSE

To predict the need for surgical intervention in patients with primary open-angle glaucoma (POAG) using systemic data in electronic health records (EHRs).

DESIGN

Development and evaluation of machine learning models.

METHODS

Structured EHR data of 385 POAG patients from a single academic institution were incorporated into models using multivariable logistic regression, random forests, and artificial neural networks. Leave-one-out cross-validation was performed. Mean area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, and Youden index were calculated for each model to evaluate performance. Systemic variables driving predictions were identified and interpreted.

RESULTS

Multivariable logistic regression was most effective at discriminating patients with progressive disease requiring surgery, with an AUC of 0.67. Higher mean systolic blood pressure was associated with significantly increased odds of needing glaucoma surgery (odds ratio [OR] = 1.09, P < .001). Ophthalmic medications (OR = 0.28, P < .001), non-opioid analgesic medications (OR = 0.21, P = .002), anti-hyperlipidemic medications (OR = 0.39, P = .004), macrolide antibiotics (OR = 0.40, P = .03), and calcium blockers (OR = 0.43, P = .03) were associated with decreased odds of needing glaucoma surgery.

CONCLUSIONS

Existing systemic data in the EHR has some predictive value in identifying POAG patients at risk of progression to surgical intervention, even in the absence of eye-specific data. Blood pressure-related metrics and certain medication classes emerged as predictors of glaucoma progression. This approach provides an opportunity for future development of automated risk prediction within the EHR based on systemic data to assist with clinical decision-making.

Systemic and Ocular Hemodynamic Risk Factors in Glaucoma

Primary open angle glaucoma (POAG) is a multifactorial disease characterized by progressive retinal ganglion cell death and visual field loss. It is known that alterations in intraocular pressure (IOP), blood pressure (BP), and ocular perfusion pressure (OPP) can play a significant role in the pathogenesis of the disease. Impaired autoregulatory capacity of ocular blood vessels may render tissues vulnerable to OPP changes and potentially harmful tissue ischemia-reperfusion damage. Vascular risk factors should be considered more important in a subgroup of patients with POAG, and especially in patients with normal tension glaucoma (NTG) with evidence of unphysiological BP response. For example, reduction of BP during the nighttime has an influence on OPP, and increased circadian OPP fluctuation, which might stand for unstable ocular blood flow, has been found to be the consistent risk factor for NTG development and progression. Central visual field may be affected more severely than peripheral visual field in NTG patients with higher 24-hour fluctuation of OPP. This review will discuss the current understanding of allegedly major systemic and ocular hemodynamic risk factors for glaucoma including systemic hypertension, arterial stiffness, antihypertensive medication, exaggerated nocturnal hypotension, OPP, and autonomic dysregulation.

Ocular perfusion pressure in glaucoma

This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma.

Ambulatory blood pressure improves prediction of cardiovascular risk: implications for better antihypertensive management

Accurate measurement of arterial pressure is necessary for diagnosis of hypertension and for assessment of its therapy. The development and growing application of ambulatory blood pressure monitoring (ABPM) furthers these goals. Use of ABPM has defined white coat hypertension (WCH) and masked hypertension (MH), important prognostic diagnoses. ABPM categorizes blood pressure in several ways that increase accuracy for diagnosis and prediction of cardiovascular risk. Measurements of blood pressure throughout the day, at night during sleep, during the morning surge, and, in some instances selected intervals can be especially valuable for both research and clinical management. ABPM is being explored for its value in measuring pulse pressure and a derived index of arterial stiffness. ABPM has also shown to be valuable for defining the effects of antihypertensive drugs therapy. Results of such studies are crucial for advancing antihypertensive management. This review will summarize the important and emerging role of ABPM in defining risk for cardiovascular disease.

Observations on degenerative changes within the optic nerve in patients with primary open glaucoma and arterial hypertension: 6-month follow-up

The authors aimed to determine the effect of the time of hypotensive drug administration on the progress of degenerative changes within the optic nerve in patients with hypertension and glaucoma. Two groups were included in the study: group A comprised patients-dippers taking drugs in the mornings, and group B comprised patients-nondippers taking drugs both in the mornings and in the evenings. After 6 months, group B showed significant drops in nocturnal diastolic blood pressure (BP) (month 1=73.27 mm Hg vs month 6=67.50 mm Hg), nocturnal mean BP (89.34 vs 84.65 mm Hg), and minimum diastolic BP (50.74 vs 44.03 mm Hg). Group B also showed significant reductions in nocturnal ocular perfusion pressure (43.0 vs 39.73), retinal nerve fiber layer thickness (131.31 vs 113.12 μm), and flow in the eye vessels. Taking hypotensive drugs in the evening may significantly decrease blood flow in the eye arteries, cause degenerative changes within the optic nerves, and result in greater loss in the field of vision.

Effects of the time of antihypertensive drugs administration on the stage of primary open-angle glaucoma in patients with arterial hypertension

Many patients with glaucoma suffer from arterial hypertension (AH). It has been proved that both AH and low blood pressure (BP) at night are important vascular risk factors for primary open-angle glaucoma (POAG). The aims of this study were to assess the severity of pathological changes within the optic nerve and characteristics of blood flow in selected arteries of the eyeball and orbit in patients with POAG and controlled hypertension, in relation to the time of hypotensive drugs administration. Eighty-eight patients with POAG and treated, controlled hypertension were examined. The patients were divided into two subgroups, consisting of group A (n = 43), in whom hypotensive drugs were dosed only in the morning and group B (n = 45), in whom hypotensive drugs were also taken in the evening. In patients who were taking hypotensive drugs also in the evening (group B), there was a statistically significant lower mean perfusion pressure at night, a greater visual field loss and reduced amplitude of evoked potentials. Our analysis showed significantly worse changes in the parameters relating to the optic nerve in patients taking hypertensive medicines in the evening and also significantly lower perfusion pressures at night.