Is there an association between migraine headache and open-angle glaucoma? Findings from the Blue Mountains Eye Study

Migraine headache and other risk factors associated with glaucoma among the adult population living in Armenia: a case-control study

PURPOSE

This study aimed to assess the association between migraine headache and glaucoma among the adult population living in Armenia.

METHODS

This case-control study recruited 145 cases with glaucoma and 250 controls without glaucoma and other ocular disorders except refractive error from Optomed Canada Diagnostic Eye Center in Armenia. A structured questionnaire contained questions on socio-demographics, family history of glaucoma and stroke, ocular health, smoking, migraine, and obstructive sleep apnea. The Migraine Screening Questionnaire assessed possible migraine and the Berlin Questionnaire measured obstructive sleep apnea.

RESULTS

The mean ages of cases and controls were 63.3 (SD = 12.3) and 39.5 (SD = 13.5), respectively. Females comprised 62.8% of cases and 69.1% of controls. A total of 17.8% of cases and 19.0% of controls had possible migraine. In the adjusted analysis older age (OR 1.17; 95% CI 1.12; 1.23), average/lower than average socio-economic status (OR 5.27; 95% CI 1.30; 21.3), and family history of glaucoma (OR 4.25; 95% CI 1.51; 11.9) were associated with high-tension glaucoma.

CONCLUSION

Timely case detection of glaucoma among those with average/low socio-economic status and those with family history of glaucoma could prevent further progression of the disease. Further studies to explore the relationship between migraine headache and specific types of glaucoma may be worthwhile.

Postmortem Analysis of Optic Nerve Head Vascularization in an Individual With Glaucoma

Reduced ocular perfusion likely contributes to glaucomatous damage at the optic nerve head (ONH). In recent decades, investigators have focused heavily on ocular perfusion pressure and other factors affecting blood flow to the eye. Comparatively, far less attention has been focused on the blood vessels themselves. Here, we asked whether glaucomatous individuals exhibit anatomical deficiencies (i.e., fewer blood vessels) in their ONH blood supply. To answer this question, we performed a systematic literature review to (1) determine how many studies have reported measuring blood vessels in the ONH and (2) whether these studies reported differences in blood vessel quantity. Additionally, we report a method for quantifying blood vessels in ex vivo human ONH preparations, including an ONH from an individual with glaucoma. Our results show that only two studies in the past 50 years have published data concerning blood vessel density in glaucomatous ONHs. Interestingly, both studies reported decreased blood vessel density in glaucoma. Consistent with this finding, we also report reduced blood vessel numbers in the superolateral quadrant of a glaucomatous individual's ONH. Vascularity in the three remaining quadrants was similar to control. Together, our findings raise the interesting possibility that individuals with a relatively sparse ONH blood supply are more likely to develop glaucoma. Future studies with larger sample sizes and more thorough quantification are necessary to determine the link more accurately between glaucoma and the blood supply to the ONH.

Ocular rigidity and neuroretinal damage in patients with vasospasticity: a pilot study

OBJECTIVE

Evidence suggests that ocular blood flow dysregulation in patients with vasospasticity could occur in response to biomechanical stimuli, contributing to optic nerve head susceptibility in glaucoma. We evaluate the role of vasospasticity in the association between ocular rigidity (OR) and neuroretinal damage, hypothesizing that low OR correlates with greater glaucoma damage in patients with vasospasticity.

DESIGN

Cross-sectional study.

PARTICIPANTS

Patients with open-angle glaucoma (OAG), suspect discs, or no glaucoma.

METHODS

OR was measured using a noninvasive, validated method developed by our group. Retinal nerve fibre layer (RNFL) and ganglion cell complex thicknesses were acquired using spectral domain optical coherence tomography. Vasospasticity was assessed by a standardized questionnaire that was based on existing validated questionnaires and adapted to our requirements. Atherosclerosis was evaluated based on Broadway and Drance's (1998) cardiovascular disease score. Correlations between OR and structural parameters were assessed in patients with vasospasticity and those with atherosclerosis.

RESULTS

Of 118 patients with either OAG (n = 67), suspect discs (n = 26), or no glaucoma (n = 25) who were recruited consecutively, 10 were classified as having vasospasticity, and 37 as having atherosclerosis. In the vasospastic group, significant correlations were found between OR and the minimum ganglion cell complex thickness (rs = 0.681, p = 0.030), the average RNFL thickness (rs = 0.745, p = 0.013), and the RNFL in the temporal quadrant (rs = 0.772, p = 0.009), indicating more damage with lower OR. Similar trends were maintained when applying multiple testing correction; however, only the eighth RNFL clock hour corresponding to the inferior-temporal peripapillary region remained significantly correlated with OR in the vasospastic group (p = 0.015). In contrast, no correlation was found in the atherosclerotic group (p > 0.05).

CONCLUSIONS

The findings of the current pilot study indicate a trend for more neuronal structural damage in less-rigid eyes of patients with vasospasticity, meaning that OR may play a greater role in glaucoma in vasospastic patients than in patients with atherosclerosis. Although these results provide interesting insight into the pathophysiology of OAG, further investigation is needed to confirm our observations.

Glaucoma awareness in Family Health Centers

This study aims to evaluate the glaucoma knowledge and awareness in individuals who visit to two Family Health Centers in a district of Istanbul. Patients and Method: This descriptive study, using a three-part questionnaire consisting of 20 questions, was carried out on individuals who applied to two Family Health Centers in a district of Istanbul between May and June 2019. Data from 260 were collected through face to face interviews. Results: A total of 44 (16.9%) participants had heard the word glaucoma before, while 179 (68.8%) said that glaucoma was treatable, 78 (30%) knew about asymptomatic course glaucoma. In addition, 47(18.1%) believed that eyes with glaucoma could not be operated, 152 (58.5%) thought that blindness resulting from glaucoma was reversible. Interestingly, 167(68.7%) participants thought that routine ophthalmologic visits should be done at least once a year, whereas 222 (86.9%) consulted an ophthalmologist less than 10 times in their lifetime. Conclusion: There was no statistically significant difference between individuals with family members that have glaucoma and those that do not, when asked about glaucoma being asymptomatic, the preventability of blindness and whether or not they have heard of glaucoma before. The study findings stress the need to spread awareness about glaucoma for prevention of glaucoma related blindness.

Caveolin-1 in vascular health and glaucoma: A critical vascular regulator and potential therapeutic target

Caveolin-1 (Cav-1) is an integral scaffolding membrane protein found in most cell types. Cav-1 has been found to contribute significantly to ocular function, with mutations of Cav-1 being associated with a genetic risk of glaucoma development. Raised intraocular pressure (IOP) is a major modifiable risk factor for glaucoma. Cav-1 may be involved in both IOP-dependent and independent mechanisms involving vascular dysregulation. Systemic vascular diseases including hypertension, diabetes and hyperlipidaemia, have been shown to be associated with glaucoma development. Cav-1 is closely interlinked with endothelial nitric oxide synthase pathways that mediate vascular function and prevent cardiovascular diseases. Endothelial nitric oxide synthase and endothelin-1 are key vasoactive molecules expressed in retinal blood vessels that function to autoregulate ocular blood flow (OBF). Disruptions in the homeostasis of OBF have led to a growing concept of impaired neurovascular coupling in glaucoma. The imbalance between perfusion and neuronal stimulation arising from Cav-1 depletion may result in relative ischemia of the optic nerve head and glaucomatous injury. OBF is also governed by circadian variation in IOP and systemic blood pressure (BP). Cav-1 has been shown to influence central BP variability and other circadian rhythms such as the diurnal phagolysosomal digestion of photoreceptor fragments and toxic substrates to maintain ocular health. Overall, the vast implications of Cav-1 on various ocular mechanisms leading to glaucoma suggest a potential for new therapeutics to enhance Cav-1 expression, which has seen success in other neurodegenerative diseases.

Decrease Retinal Thickness in Patients with Chronic Migraine Evaluated by Optical Coherence Tomography

The purpose of this study is to determine the possible alterations that may occur in the thickness of the retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), and macular thickness in patients with chronic migraines compared with healthy controls. Hence, we examined some of the possibilities that are offered by optical coherence tomography (OCT) in order to study different neurological diseases and to study its application, in this case, how it may be applied to patients with chronic migraines. This was an observational cross-sectional study in adults aged 18-65 years. The study group consisted of 90 patients (90 eyes) with chronic migraines who met the inclusion criteria, and 90 healthy controls (90 eyes) matched for age and sex. Retinal thickness was measured by spectral domain OCT (SD-OCT). The thickness of the superior quadrant of the peripapillary RNFL, as well as the mean thickness in the macula, RNFL macular, and GCL was significantly thinner in chronic migraine patients than in healthy controls (p ≤ 0.05). Chronic migraines are associated with a decrease in retinal thickness which is detectable by an OCT diagnostic technique. The quantification of the axonal damage could be used as a biomarker to help in the diagnosis and monitoring of this pathology. Further studies will be needed to confirm these findings.

Predictors of Early Onset Glaucoma

Purpose/Relevance

To determine the influence of hypertension (HTN), type 2 diabetes (DM2), migraine, and obstructive sleep apnea (OSA) on the onset of primary open-angle glaucoma (POAG) to enhance predictive accuracy.

Methods

In this cross-sectional study, data for 389 eligible patients with POAG were collected through medical records review and phone surveys. All data were assessed collectively using stepwise multiple regression analysis to determine the relative contribution to age at POAG diagnosis. We used the following groups, based on age at diagnosis, HTN for patients with or without DM2 (model 1), HTN for patients with DM2 (model 2), DM2 for patients with or without HTN (model 3), and DM2 for patients with HTN (model 4).

Results

In model 1, age at HTN diagnosis was associated with age at POAG diagnosis (β = 0.14; 95% CI, 0.01–0.26, p = 0.04). In model 2, age at HTN diagnosis was not associated with age at POAG diagnosis (p > 0.05). In model 3, age at DM2 diagnosis was associated with age at POAG diagnosis (β = 0.37; 95% CI 0.16–0.58, p = 0.001). In model 4, age at DM2 diagnosis was associated with age at POAG diagnosis (β = 0.40; 95% CI 0.00–0.15, p = 0.003). Asian race/ethnicity was associated with early onset of POAG in model 3 (β = −6.44; 95% CI −12.34–0.54, p = 0.033). OSA and migraine did not influence the onset of POAG.

Conclusion

Our study found that the diagnosis of DM2 and HTN at an earlier age is associated with the early onset of POAG.

High myopia as risk factor for the 10-year incidence of open-angle glaucoma in the Beijing Eye Study

PURPOSE

To assess the 10-year incidence of open-angle glaucoma (OAG) and its associations in an adult Chinese population.

METHODS

Longitudinal observational population-based study. Out of 4439 participants aged 40+ years participating in the Beijing Eye Study in 2001, 2695 individuals (60.7%) were re-examined in 2011, while 397 participants had died (8.5%).

RESULTS

Incident OAG was found in 75 participants among 2494 individuals free of glaucoma at baseline. The 10-year OAG incidence (mean: 3.0%; 95% CI 2.5 to 3.5) increased from 1.8% (95% CI 1.3 to 2.4) in individuals aged 40-49 years, to 5.9% (95% CI 3.1 to 9.6) in participants aged 70+ years. OAG incidence was highest in the high myopia group (13.3%±6.3%, OR: 7.3; 95% CI 3.3 to 16.3), followed by the moderately myopic group (8.1%±4.3%, OR: 4.2; 95% CI 2.0 to 8.8) and the low myopic group (6.2%±2.8%, OR: 3.2; 95% CI 1.7 to 5.8), as compared with the emmetropic/hyperopic group (2.1%±0.8%). In multivariable analysis, higher OAG incidence was associated with older age (OR: 1.06; 95% CI 1.03 to 1.09), longer axial length (OR: 1.72; 95% CI 1.45 to 2.05), higher intraocular pressure (IOP) in 2001 (OR: 1.18; 95% CI 1.08 to 1.29), higher vertical cup/disc ratio (VCDR) (OR: 60.8; 95% CI 6.7 to 556) and thinner central corneal thickness (CCT) (OR: 0.98; 95% CI 0.97 to 0.99).

CONCLUSIONS

In a 10-year follow-up, high myopia was a major risk factor for the development of OAG with a 7.3-fold risk increase as compared with emmetropic eyes. Higher age, IOP, VCDR and thinner CCT were additionally related with an increased OAG incidence. The findings may be of importance to clinical protocols and screening strategies.

Longitudinal In Vivo Changes in Radial Peripapillary Capillaries and Optic Nerve Head Structure in Non-Human Primates With Early Experimental Glaucoma

Purpose

There is conflicting evidence regarding whether a loss of radial peripapillary capillaries (RPCs) precedes neuronal loss in glaucoma. We examined the time course of in vivo changes in RPCs, optic nerve head (ONH) structure, and retinal nerve fiber layer thickness (RNFLT) in experimental glaucoma (EG).

Methods

Spectral domain optical coherence tomography images were acquired before and approximately every two weeks after inducing unilateral EG in nine rhesus monkeys to quantify mean anterior lamina cribrosa surface depth (ALCSD), minimum rim width (MRW), and RNFLT. Perfused RPC density was measured from adaptive optics scanning laser ophthalmoscope images acquired on the temporal half of the ONH. The time of first significant change was quantified as when values fell and remained outside of the 95% confidence interval established from control eyes.

Results

Mean ALCSD and/or MRW were the first parameters to change in eight EG eyes. RPC density changed first in the ninth. At their first points of change, mean ALCSD posteriorly deformed by 100.2 ± 101.2 µm, MRW thinned by 82.3 ± 65.9 µm, RNFLT decreased by 25 ± 14 µm, and RPC density decreased by 4.5 ± 2.1%. RPC density decreased before RNFL thinning in 5 EG eyes. RNFLT decreased before RPC density decreased in two EG eyes, whereas two EG eyes had simultaneous changes.

Conclusions

In most EG eyes, RPC density decreased before (or simultaneous with) a change in RNFLT, suggesting that vascular factors may play a role in axonal loss in some eyes in early glaucoma.

The eye in migraine: a review of retinal imaging findings in migraine

Migraine is a common headache disorder with neurovascular involvement. Because eyecare practitioners are likely to encounter people with migraine in their everyday practice, it is important to understand how migraine might impact on ocular health. In this narrative review, we provide an update on the latest ophthalmic imaging evidence for retinal involvement in migraine, derived from studies of retinal structure and retinal vascular perfusion using spectral domain and swept source optical coherence tomography (OCT) and OCT angiography. Combined structural OCT evidence from a recent meta-analysis indicates subtle and non-specific thinning of the peripapillary retinal nerve fibre layer (RNFL) in people with migraine, whereas there is little consistent evidence for structural abnormalities of the macular region. Recent advances in OCT angiography technology have also provided an opportunity to visualise microstructural damage and vascular dysregulation in the eyes of people with migraine. However, given that OCT and OCT angiography studies have been exclusively cross-sectional, it is not possible to demonstrate the causal effect of migraine events. Furthermore, the lack of common methodology (different ophthalmic imaging devices and analysis algorithms), and very limited datasets (small samples, heterogenous migraine groups), lead to an inability to make strong conclusions regarding the nature of altered retinal structure and vascular perfusion in migraine. Nevertheless, we discuss the clinical implications of such observations for eyecare practitioners and provide practical advice for the monitoring and management of patients with a history of migraine.

Evaluation of retinal and optic nerve vasculature by optic coherence tomography angiography in Migraine with Aura

PURPOSE

This study aimed to evaluate the retina by optic coherence tomography angiography (OCTA) in patients with migraine with aura (MA) in comparison with healthy controls.

MATERIALS AND METHODS

A total of 60 patients with MA and 56 control subjects who applied to the Ophthalmology Clinic of Dicle University between January 2020 and February 2020 were included in this study. In all patients, the vascular density (VD) of the radial peripapillary capillaries (RPCs) and optic nerve head (ONH), the VD of deep and superficial macular vascular networks, and foveal avascular zone (FAZ) were measured.

RESULTS

Patients with MA showed reduced VD measurements of the nasal and inferotemporal ONH, inferonasal RPCs, and deep macular plexus. No statistically significant difference was observed in the superficial macular VD values between the study groups. The majority of patients with MA showed hypertrophy in the deep FAZ.

CONCLUSION

There was a decrease in VD measurements in the deep macular capillary plexus, ONH, and peripapillary capillaries and hypertrophy in the deep FAZ in patients with MA. According to these results, patients with MA may have an increased risk of developing ocular and systemic vascular complications. Therefore, OCTA can be used to evaluate systemic and ocular hypoperfusion in patients with MA.

Feasibility of MRI to assess differences in ophthalmic artery blood flow rate in normal tension glaucoma and healthy controls

Purpose

To examine feasibility of phase‐contrast magnetic resonance imaging (PCMRI) and to assess blood flow rate in the ophthalmic artery (OA) in patients with normal tension glaucoma (NTG) compared with healthy controls.

Methods

Sixteen patients with treated NTG and 16 age‐ and sex‐matched healthy controls underwent PCMRI using a 3‐Tesla scanner and ophthalmological examinations. OA blood flow rate was measured using a 2D PCMRI sequence with a spatial resolution of 0.35 mm².

Results

The blood flow rate in the NTG group was 9.6 ± 3.9 ml/min [mean ± SD] compared with 11.9 ± 4.8 ml/min in the control group. Resistance Index (RI) and Pulsatility Index (PI) were 0.73 ± 0.08 and 1.36 ± 0.29, respectively, in the NTG group and 0.68 ± 0.13 and 1.22 ± 0.40, respectively, in the healthy group. The mean visual field index (VFI) was 46% ± 25 for the worse NTG eyes. The measured differences observed between the NTG group and the control group in blood flow rate (p = 0.12), RI (p = 0.18) and PI (p = 0.27) were non‐significant.

Conclusions

This case–control study, using PCMRI, showed a slight, but non‐significant, reduction in OA blood flow rate in the NTG patients compared with the healthy controls. These results indicate that blood flow may be of importance in the pathogenesis of NTG. Considering that only a limited portion of the total OA blood flow supplies the ocular system and the large inter‐individual differences, a larger study or more advanced PCMRI technique might give the answer.

Headaches related to latanoprost in open-angle glaucoma

Clinical relevance: The existing notion that topical latanoprost can lead to symptoms of headaches by reporting three cases of headache symptoms that developed following instillation of latanoprost prescribed as first-line therapy for newly diagnosed primary open-angle glaucoma (POAG) is explored in this case series.Background: Prostaglandin analogues (PGAs) are often used as first-line treatment in the treatment of POAG. An uncommon and infrequently reported side effect of PGAs is headaches.Methods: A retrospective review of patient records was conducted on patients seen at the Centre for Eye Health between April 2016 and August 2017. Clinical findings, including outcomes following interventions such a punctal occlusion, as well as the proposed pharmacological mechanism underlying this phenomenon are presented and discussed.Results: Case 1 is a 62-year-old Caucasian male diagnosed with POAG and prescribed latanoprost in both eyes. At the follow-up visit, he reported waking up in with a dull throbbing headache following instillation of the eye drops the night before. Case 2 is a 58-year-old Asian male with POAG prescribed latanoprost to both eyes. Within a week, he developed symptoms of recurrent progressively worsening headaches post-instillation which persisted into the morning. Case 3 is a 75-year-old Caucasian male with POAG prescribed latanoprost for both eyes. He developed latanoprost sensitivity as well as headache symptoms associated with the eye drops which resolved followed its cessation. All patients reported initial symptoms of headaches associated with latanoprost use however the headaches were not persistent with intermittent punctal occlusion (cases 1 and 2) or intra-class drug rechallenge (case 3).Conclusion: Although there may be a yet-undiscovered link between a headache response and latanoprost, these cases call to question the pharmacological relationship between latanoprost and headache symptoms. A systemic approach to critically examine the pathophysiological link between pharmacological therapy and potential adverse effects is proposed.

Retinal nerve fiber layer changes in migraine: a systematic review and meta-analysis

BACKGROUND

Migraine is one of the most common disabling diseases in the world. Its recurrent attacks may lead to abnormalities in the structure of the brain and retina. An increasing number of studies have investigated retinal nerve fiber layer (RNFL) thickness alterations in migraine by the optical coherence tomography (OCT); however, no consensus has yet reached.

METHOD

We searched Pubmed, Embase, and Web of Science databases to identify studies that investigated RNFL thickness in migraine by OCT measurement and performed a meta-analysis of eligible studies.

RESULTS

Twenty-six studies were included in the meta-analysis, comprising 1530 migraine patients and 1105 healthy controls. The mean RNFL thickness was thinner in the migraine group compared to the control group (SMD =- 0.53). In the subgroup analyses, RNFL thickness were decreased most significantly in the superior (SMD = - 0.71) and inferior (SMD = - 0.63) quadrants among all quadrants. Migraine with aura (SMD = - 0.91) showed a greater effect size of RNFL thickness reduction than migraine without aura (SMD =- 0.47). Spectral-domain OCT (SMD = - 0.55) seems more sensitive to detect RNFL thickness reduction than time-domain OCT (SMD = - 0.44). In addition, age, sex, disease duration, attack frequency, and intraocular pressure were not significantly associated with RNFL thickness.

CONCLUSIONS

The findings from our comprehensive meta-analysis with large datasets strengthen the clinical evidence of the RNFL thickness reduction in migraine. RNFL thickness via spectral-domain OCT measurement demonstrates the potential role in differentiating patients with migraine, especially migraine with aura, from healthy controls.

Retinal oximetry in glaucoma: investigations and findings reviewed

Abnormalities of the retinal blood supply have been widely implicated in primary open-angle glaucoma (POAG). Impaired blood supply to the retina and optic nerve head (ONH) may be a primary pathophysiologic mechanism contributing to POAG ('vascular hypothesis'). However, the decreased metabolic activity of atrophic tissue is itself known to induce both vascular changes and decreased blood flow due to reduced oxygen demand. Therefore, primary nonvascular factors could potentially induce glaucomatous atrophy, with subsequent secondary vascular pathology ('mechanical hypothesis'). Retinal oximetry holds great promise in the investigation of glaucoma pathogenesis, as it can provide useful data on retinal metabolic oxygen demand, especially when combined with measurements of retinal blood flow. This review surveys the research on retinal metabolism in POAG using spectroscopic retinal oximetry. The use of mathematical models in combination with oximetric data to investigate the role of retinal metabolism and oxygen supply in POAG is also discussed.

Impact of laser iridotomy on headache symptoms in angle-closure subjects

BACKGROUND

Migraine symptoms are frequently referred by glaucoma patients. Although most studies analyze headache in the acute setting of angle closure, many patients with chronic occludable angles also complain of headaches. The aim of this study was to determine the impact of laser peripheral iridotomy (LPI) on the magnitude and frequency of headache symptoms in patients with occludable angles.

METHODS

Prospective cohort study. Patients with indication for prophylactic LPI due to occludable iridocorneal angle were included. Headache symptoms were assessed before and at least 4 weeks after LPI using the Headache Impact Test-6 (HIT-6) questionnaire. A HIT-6 score of ≥ 50 points was labeled as a clinically significant headache.

RESULTS

Thirty-one subjects were included. Prophylactic LPI was performed in 60 eyes, as 2 patients were pseudophakic in the fellow eye. Baseline HIT-6 score was 59.9 ± 11.8, with over three quarters of these patients scoring higher than 50 points (n = 24). A statistically significant reduction in HIT-6 score was found after LPI treatment (45.4 ± 7.7, p < 0.01). Sub-analysis within the clinically symptomatic subjects disclosed a significant improvement after treatment in this group (baseline, 65.3 ± 6.2 vs post-LPI 46.2 ± 8.3, p < 0.01), with a high baseline HIT-6 score being predictive of a symptomatic improvement after LPI (χ²(8) = 15.3, p = 0.001). This is mimicked from the patient's perspective, as the two subjective questions after LPI, concerning pain intensity and frequency, report that 79.2% had a statistically significant improvement of the headaches.

CONCLUSIONS

Within our sample, the majority of patients with occludable angles had clinically relevant headaches. LPI provided symptomatic relief in the majority of those patients with high HIT-6 scores. Further studies are needed to explore the relationships between headache and angle anatomy.

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.

The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

Purpose

Glaucoma is more common in urban populations than in others. Ninety percent of the world's population are exposed to air pollution above World Health Organization (WHO) recommended limits. Few studies have examined the association between air pollution and glaucoma.

Methods

Questionnaire data, ophthalmic measures, and ambient residential area air quality data for 111,370 UK Biobank participants were analyzed. Particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5) was selected as the air quality exposure of interest. Eye measures included self-reported glaucoma, intraocular pressure (IOP), and average thickness of macular ganglion cell-inner plexiform layer (GCIPL) across nine Early Treatment Diabetic Retinopathy Study (ETDRS) retinal subfields as obtained from spectral-domain optical coherence tomography. We examined the associations of PM2.5 concentration with self-reported glaucoma, IOP, and GCIPL.

Results

Participants resident in areas with higher PM2.5 concentration were more likely to report a diagnosis of glaucoma (odds ratio = 1.06, 95% confidence interval [CI] = 1.01-1.12, per interquartile range [IQR] increase P = 0.02). Higher PM2.5 concentration was also associated with thinner GCIPL (β = -0.56 μm, 95% CI = -0.63 to -0.49, per IQR increase, P = 1.2 × 10-53). A dose-response relationship was observed between higher levels of PM2.5 and thinner GCIPL (P < 0.001). There was no clinically relevant relationship between PM2.5 concentration and IOP.

Conclusions

Greater exposure to PM2.5 is associated with both self-reported glaucoma and adverse structural characteristics of the disease. The absence of an association between PM2.5 and IOP suggests the relationship may occur through a non-pressure-dependent mechanism, possibly neurotoxic and/or vascular effects.

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.

The Psychophysical Assessment of Hierarchical Magno-, Parvo- and Konio-Cellular Visual Stream Dysregulations in Migraineurs

Introduction

Although conscious, image-forming illusions have been noted in migraine, few studies have specifically sought to collectively evaluate the role of all three parallel visual processing streams in the retinogeniculostriate pathway involved with image-forming vision and their implications in the development of migraine symptoms.

Methods

We psychophysically assessed the functionality of the inferred magnocellular (MC), parvocellular (PC), and koniocellular (KC) streams at different hierarchical loci across three clinical groups: individuals who experience migraine with aura (MA; n=13), experience migraine without aura (MWO; n=14), and Controls (n=15). Participants completed four experiments: Experiment 1 designed to assess retinal short-wavelength-sensitive (S-) cone sensitivities; Experiment 2 intended to measure postretinal temporal and spatiochromatic contrast sensitivities; Experiment 3 intended to assess postretinal spatiotemporal achromatic contrast sensitivities; and Experiment 4 designed to measure thalamocortical color discriminations along the three cone-excitation axes.

Results

S-cone deficits were revealed with greater retinal areas being affected in MA compared to MWO participants. Findings across the four experiments suggest a prominent retinal locus of dysfunction in MA (lesser in MWO) with potential feedforward compensations occurring within the KC visual stream.

Conclusion

Complex, integrative network compensations need to be factored in when considering the dysregulating influences of migraine along the visual pathway.

Determinants of maximum cup depth in non-glaucoma and primary open-angle glaucoma subjects: a population-based study

Background/objectives

To study the associations of intraocular pressure (IOP) and retinal vessel diameters: central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) with the maximum cup depth (MCD) in subjects with and without POAG.

Subjects/methods

Eligible subjects from the Handan Eye Study. All participants underwent physical and comprehensive eye examinations. Univariable and multivariable linear regression models assessed the association between MCD and other parameters.

Results

Four thousand one hundred and ninety-four eligible nonglaucoma and 40 POAG subjects were analyzed. On univariable analysis, deeper MCD was significantly associated with younger age, male gender, lower systolic blood pressure (BP), higher IOP, higher estimated cerebro-spinal fluid pressure (ECSFP), lower estimated trans-laminal cribrosa pressure difference (ETLCPD), longer axial length, narrower CRAE, narrower CRVE, larger disc area (DA) and a lower prevalence of hypertension and diabetes. On multivariable analysis, significant independent determinants of MCD were larger DA (P < 0.001; beta: 0.042; B: 0.20; 95% CI: 0.19, 0.22), younger age (P < 0.001; beta: −0.09; B: −0.002; 95% CI: −0.003, −0.001), higher IOP (P < 0.01; beta: 0.040; B: 0.003; 95% CI: 0.001, 0.005), and narrower CRAE (P < 0.001; beta: −0.06; B: −0.001; 95% CI: −0.001, −0.0003). On adding ECSFP and ETLCPD to the model, MCD was associated with IOP but not with estimated CSFP and TLCPD. A 1 μm decrease in CRAE or 1 mmHg increase of IOP was associated with a 1 μm increase of MCD (P < 0.001) and 3 μm increase of MCD respectively (P = 0.009).

Conclusions

Narrow CRVE and higher IOP are associated with an increase in MCD.

Prevalence, incidence, and risk factors of primary open-angle glaucoma - a cohort study based on longitudinal data from a German public health insurance

Background

This study estimates the prevalence and incidence rates of primary open -angle glaucoma (POAG) as well as risk factors based on a dataset from the largest German health insurance company.

Methods

A random sample of 250,000 persons at age 50+ of the Allgemeine Ortskrankenkasse (AOK) from 2010 to 2013 was used. Selected risk factors of POAG incidence were analyzed using multivariate Cox proportional hazard models.

Results

The age-standardized prevalence of POAG at age 50+ in 2010 was 2.79% (95%-CI: 2.72–2.85%). The age-standardized total incidence rate was 0.38 (0.36–0.39) per 100 person-years. Sex differences were significant for total prevalence and total incidence rates, with higher prevalence and incidence rates for women compared to men. The Cox model revealed a strong age effect, a significantly 19% higher incidence for women (p ≤ 0.001), injuries of the eye and orbit (175%, p ≤ 0.001), degeneration of iris and ciliary body (155%, p = 0.022), myopia (155%, p ≤ 0.001), retinal vascular occlusions (134%, p ≤ 0.001), hypertension (13%, p ≤ 0.001) and diabetes mellitus (23%, p ≤ 0.001).

Conclusion

Health claims data are an important data source for estimating POAG occurrence and help overcome the problems of small sample sizes. These results may help to understand the causal pathways of POAG and to develop intervention strategies to increase the awareness of patients and physicians with the aim of reducing POAG incidence.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6935-6) contains supplementary material, which is available to authorized users.

Migraine and increased risk of developing open angle glaucoma: a population-based cohort study

Background

Migraine is linked to endothelial dysfunction and is considered to be a systemic vasculopathy. Interestingly, systemic vascular diseases also occur in glaucoma patients and are considered to be vascular risk factors. Whether migraine is simply a concomitant condition in glaucoma patients or a risk factor per se for glaucoma remains unknown. Thus, in the present study, we investigated the risk for open angle glaucoma (OAG) in migraineurs using a 10-year follow-up study that employed a nationwide population-based dataset in Taiwan.

Methods

This retrospective matched-cohort study used data sourced from the Longitudinal Health Insurance Database 2000. We included 17,283 subjects with migraine in the study cohort and randomly selected 69,132 subjects from the database for the comparison group. Each subject in this study was individually traced for a 10-year period to identify those subjects who subsequently received a diagnosis of OAG. The age-adjusted Charlson’s comorbidity index (ACCI) score was utilized to compute the burden of comorbidity in each subject. Multivariate regression analysis was used to assess risk factors for OAG in migraineurs. Cox proportional hazards regression was performed to compare the 10-year risk of OAG between the migraineurs and the comparison cohort.

Results

Migraineurs had more vascular comorbidities than the comparison cohort. The overall incidence of OAG (per 1000 person-years) was 1.29 and 1.02, respectively, for migraineurs and the comparison cohort during the 10-year follow-up period. Age, hyperlipidemia, and diabetes mellitus were three significant risk factors for OAG in migraineurs. After adjusting for patients’ age and vascular comorbidities, migraineurs were found to have a 1.68-fold (95% confidence interval [CI], 1.20–2.36) greater risk of developing OAG than the comparison cohort, in subjects with an ACCI score of 0. This association became statistically nonsignificant in subjects with ACCI scores of 1–2 or ≥ 3.

Conclusion

Migraine is associated with a higher risk of OAG for patients with no comorbidity who are aged under 50 years.

Disc haemorrhages in Polish Caucasian patients with normal tension glaucoma

AIM

The aim of this observational study was to evaluate the epidemiology of disc haemorrhages (DH) in Polish patients with normal tension glaucoma (NTG) and their association with some risk factors.

MATERIAL AND METHODS

The group studied consisted of 274 Caucasian patients with NTG (410 eyes) divided into those with disk haemorrhages (DH+, = 94 eyes in 81 patients) and those without disc haemorrhages (DH-, = 316 eyes in 193 patients). Ophthalmic examinations with visual field (VF) testing were carried out in these patients every 3 months for at least 18 months. The medical history was recorded taking glaucoma, other ophthalmic diseases, chronic general disorders and vascular risk factors into account.

RESULTS

Unilateral and bilateral DH were observed more frequently in women (p = 0.0010). Maximum IOP was significantly higher in the DH+ group (p = 0.000026). Notches and peripapillary atrophy were found with similar frequency in DH+ and DH- patients (p = 0.4631). The mean defect (MD) in the VF at the time of diagnosis was lower in the DH+ group (-6.27 dB) than in the DH group (-10.14 dB), (p = 0.000055). The initial MD in the DH+ group had a positive correlation with maximum initial IOP. A progressive loss of VF was observed in 206 eyes with NTG (50.2%), with a mean of 0.72 dB/year. The progression was more frequent in DH+ patients (78.4% versus 41.1%), but there were no statistically significant differences in the rate of progression between DH+ and DH- patients (p = 0.46). The morphology of early scotoma depended on the presence of DH (p < 0.00001), and early scotoma in the DH+ group was more frequently localized paracentrally. There was a significant difference in a number of antiglaucoma drops between DH+ and DH- patients (p < 0.00001). There were no differences in the frequency of migraines between both groups (p = 0.31). General hypotension was observed with similar frequency in the DH+ DH- groups (p = 0.3). General hypertension was less frequent in DH+ patients (p = 0.041), especially in women (p = 0.000027). Diabetes mellitus (DM) was significantly less frequent (21.3%) in patients with DH+ (3.7%) than in the DH- group (p = 0.000852), especially among the women (p = 0.000216).

CONCLUSION

In our study, DH were more frequent both unilaterally and bilaterally in women. Initial intraocular pressure (IOP) was higher in NTG patients with DH, and early scotoma was localized in the paracentral area of the VF. Disc haemorrhages (DH) were less frequent in women with general hypertension and with diabetes mellitus.

Accuracy of peripapillary versus macular vessel density in diagnosis of early to advanced primary open angle glaucoma

PURPOSE

To evaluate macular and peripapillary vessel density (mVD, pVD) using optical coherence tomography angiography (OCT-A) in healthy subjects, patients with ocular hypertension (OHT) and primary open-angle glaucoma (POAG) patients.

METHODS

In this prospective observational study, OCT-A images were obtained from 60 eyes of 36 healthy, ocular hypertension (OHT), preperimetric glaucoma (PPG), early glaucoma (EG) and moderate and advanced POAG subjects. Superficial mVD was acquired over a 6×6-mm cube centered on the foveal avascular zone and pVD over a 4.5×4.5-mm cube centered on the optic disc. Peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell complex (GCC) thickness was calculated using spectral-domain OCT. Correlations between vascular, structural and Humphrey VF indices were evaluated (Spearman's rank correlation coefficient).

RESULTS

Median pVD and mVD in the PPG eyes were lower than in healthy eyes (51.87% and 47.23% versus 55.70% and 53.61%, respectively; P<0.001 and P=0.003), but higher than in mild glaucoma eyes (46.21% and 41.98%, P<0.001 compared to normal eyes) and moderate to advanced glaucoma eyes (37.45% and 39.89%, P<0.0001 compared to normal eyes). The highest correlations were found between structural parameters and pVD (r=0.87 and 0.86 for pRNFL and GCC, P<0.0001), followed by mVD (r=0.69 for both pRNFL and GCC, P<0.0001). Correlations with mean VF sensitivity were similar for pVD and mVD (r=0.61 and 0.56) and for GCC and pRNFL (r=0.60 and 0.52, P<0.0001 for all).

CONCLUSIONS

VD measured with OCT-A shows reduction in POAG. Detection of this damage differentiates PPG from normal and perimetric POAG eyes with a high correlation with structural parameters. Peripapillary VD accuracy is higher than mVD in detecting the disease. These results suggest that OCT-A could improve POAG diagnosis and understanding of the pathophysiologic mechanisms behind glaucoma.

Migraine as a risk factor for primary open angle glaucoma: A systematic review and meta-analysis

Migraine is increasingly being reported as a risk factor for primary open angle glaucoma (POAG). However, studies aimed to investigate this association yielded conflicting results. To assess the consistency of the data on the topic, we performed a systematic review and meta-analysis. A systematic literature search from Embase, Web of Science, and PubMed was performed to identify relevant studies on the relationship between migraine and POAG. Random effects models were used to estimate the pooled relative risks (RRs) with 95% confidence intervals (95% CIs) in this meta-analysis. A total of 11 studies meeting the inclusion criteria were included in this meta-analysis. Our findings showed an RR of developing POAG of 1.24 (95% CI = 1.12-1.37) in migraine patients. No evidence of significant heterogeneity was detected across studies (P = .071; I = 41.7%). This association was not modified by the glaucoma type of the included patients. A significant association was observed in case-control design studies, but not in cohort design studies. Little evidence of publication bias was found. The findings of this meta-analysis suggest that migraine can significantly increase the risk of the development of POAG. However, the cohort study design failed to identify this association. Whether migraines can significantly increase the risk of developing POAG is still controversial.

Association of intraocular pressure-related factors and retinal vessel diameter with optic disc rim area in subjects with and without primary open angle glaucoma

IMPORTANCE

The data may support the notion that the intra-ocular pressure (IOP)-related factors and vascular factors were implicated concurrently in glaucomatous optic nerve damage.

BACKGROUND

To study the association of intraocular pressure (IOP)-related factors, IOP, trans-lamina cribrosa pressure difference (TLCPD), cerebrospinal fluid pressure (CSFP) and retinal vessel diameters (RVD), central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) with neuro-retinal rim area (RA).

DESIGN

A population-based, cross-sectional study.

PARTICIPANTS

A total of 6830 people aged 30 years and over.

METHODS

All participants underwent a comprehensive eye examination, fundus photograph-based measurements of RVD and Heidelberg retinal tomogram (HRT) measurement of optic disc.

MAIN OUTCOME MEASURES

RA, CRAE, CRVE, IOP, body mass index (BMI), CSFP and TLCPD.

RESULTS

Primary open-angle glaucoma (POAG) was diagnosed using two separate methods: 67 from expert consensus, and 125 from the International Society of Geographical and Epidemiologic Ophthalmology (ISGEO) classification. After excluding of those with high myopia or without gradable HRT images, 4194 non-glaucoma and 40 POAG were analysed for determinants of RA. On multivariable analysis determinants of reduced RA were POAG (P < 0.001), higher IOP (P = 0.03), higher refractive error (P < 0.01), longer axial length (P = 0.01), CRVE (P < 0.001), lower BMI (P = 0.015), older age (P < 0.001) smaller disc area (P < 0.001) and higher TLCPD (P = 0.03). When age and/or BMI were omitted from the model, reduced RA was also associated with lower CSFP (P < 0.001).

CONCLUSIONS AND RELEVANCE

Reduced RA is associated with narrow CRVE and higher IOP or lower CSFP. The data supports the concurrent role of IOP-related and vascular factors in glaucomatous optic nerve damage.

Increased stroke risk among patients with open-angle glaucoma: a 10-year follow-up cohort study

BACKGROUND

Although several studies showed the association between stroke and open-angle glaucoma (OAG), there is still lack of longitudinal studies based on large populations. Therefore, in this study, we investigated the risk of stroke after OAG diagnosis over a 10-year follow-up period.

METHODS

We performed a retrospective nationwide propensity score-matched cohort study. OAG and comparison groups were selected from a large database from the Korean National Health Insurance Service, comprising 1 025 340 random subjects. The OAG group comprised patients with an initial diagnosis of OAG between January 2004 and December 2007 (n=1520), and the comparison group comprised randomly selected patients (five per glaucoma patient; n=7570). Each cohort was tracked until 2013 for stroke development. Cox proportional hazard regression analysis was performed to determine possible association RESULTS: OAG was associated with increased stroke incidence (HR=1.20, 95% CI 1.03 to 1.40). Hypertension, diabetes mellitus, chronic renal failure, atrial fibrillation, hyperlipidaemia, increasing age and male gender also increased the incidences of stroke. Risk of stroke for patients with OAG was greater in the older age group (≥65 years, HR=1.23, 95% CI 1.02 to 1.47) than in the younger age group (<65 years, HR=1.12, 95% CI 0.86 to 1.46), and greater in males (HR=1.31, 95% CI 1.06 to 1.60) than in females (HR=1.10, 95% CI 0.88 to 1.38).

CONCLUSIONS

Patients who were diagnosed with OAG were more likely to experience subsequent stroke than comparison group without OAG, and the risk was greater for older adults and males.

Retinal vasculature in glaucoma: a review

Despite the critical impact of glaucoma on global blindness, its aetiology is not fully characterised. Elevated intraocular pressure is highly associated with glaucomatous optic neuropathy. However, visual field loss still progresses in some patients with normal or even low intraocular pressure. Vascular factors have been suggested to play a role in glaucoma development, based on numerous studies showing associations of glaucoma with blood pressure, ocular perfusion pressure, vasospasm, cardiovascular disease and ocular blood flow. As the retinal vasculature is the only part of the human circulation that readily allows non-invasive visualisation of the microcirculation, a number of quantitative retinal vascular parameters measured from retinal photographs using computer software (eg, calibre, fractal dimension, tortuosity and branching angle) are currently being explored for any association with glaucoma and its progression. Several population-based and clinical studies have reported that changes in retinal vasculature (eg, retinal arteriolar narrowing and decreased fractal dimension) are associated with optic nerve damage and glaucoma, supporting the vascular theory of glaucoma pathogenesis. This review summarises recent findings on the relationships between quantitatively measured structural retinal vascular changes with glaucoma and other markers of optic nerve head damage, including retinal nerve fibre layer thickness. Clinical implications, recent new advances in retinal vascular imaging (eg, optical coherence tomography angiography) and future research directions are also discussed.

Glaucoma history and risk factors

Apart from the risk of developing glaucoma there is also the risk that it is not detected and irreversible loss of vision ensues. Some studies of methods of glaucoma diagnosis have examined the results of instrument-based examinations with great if not complete reliance on objective findings in arriving at a diagnosis. The very valuable advances in glaucoma detection instrument technologies, and apparent increasing dependence on them, may have led to reduced consideration of information available from a patient history in those studies. Dependence on objective evidence of glaucomatous pathology may reduce the possibility of detecting glaucoma suspects or patients at risk for becoming glaucoma suspects. A valid positive family history of glaucoma is very valuable information. However, negative family histories can often be unreliable due to large numbers of glaucoma cases being undiagnosed. No evidence of family history is appropriate rather than no family history. In addition the unreliability of a negative family history is increased when patients with glaucoma fail to inform their family members. A finding of no family history can only be stated as no known family history. In examining the potential diagnostic contribution from a patient history, this review considers, age, frailty, race, type and degree of refractive error, systemic hyper- and hypotension, vasospasm, migraine, pigmentary dispersion syndrome, pseudoexfoliation syndrome, obstructive sleep apnea syndrome, diabetes, medication interactions and side effects, the degree of exposure to intraocular and intracranial pressure elevations and fluctuations, smoking, and symptoms in addition to genetics and family history of the disease.

Visual Field Progression is Associated with Systemic Concentration of Macrophage Chemoattractant Protein-1 in Normal-Tension Glaucoma

PURPOSE

To investigate the associations between endothelin-1 (ET-1) and macrophage chemoattractant protein-1 (MCP-1) levels and visual field (VF) progression in normal-tension glaucoma (NTG).

METHODS

We conducted a prospective, longitudinal study in 71 patients with NTG. Blood samples from all subjects were assayed for ET-1 and MCP-1 concentrations, and baseline ophthalmic examinations, including the VF, were performed. Baseline data were compared with follow-up data over 3 years.

RESULTS

After 3 years of follow-up, 14 of the 71 patients showed VF progression, and the systemic MCP-1 level was significantly associated with VF progression (r = 0.318, p = 0.007). Multiple regression analysis showed that VF progression was significantly associated with MCP-1 (odds ratio, OR = 1.021, 95% CI = 1.003-1.040; p = 0.020) and optic disc hemorrhage (ODH; OR = 1.573; 95% CI = 1.140-2.170; p = 0.023).

CONCLUSIONS

Systemic MCP-1 levels were associated with VF progression in patients with NTG.

Comparison of Retinal Vessel Diameter Between Open-Angle Glaucoma Patients With Initial Parafoveal Scotoma and Peripheral Nasal Step

PURPOSE

To compare retinal vessel diameters (RVDs) between open-angle glaucoma (OAG) patients with initial parafoveal scotoma (PFS) and those with initial peripheral nasal step (PNS).

DESIGN

Retrospective, cross-sectional study.

METHODS

We enrolled 151 eyes of 151 patients with OAG (83 with normal-tension glaucoma [NTG] and 68 with primary open-angle glaucoma [POAG]). The patients were categorized into the PFS and PNS groups according to the location of the initial visual field (VF) defect. Clinical characteristics and RVD indices-central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE)-were compared between the groups. Subgroup analyses were conducted in the NTG and POAG groups.

RESULTS

Forty-six patients had PFS and 105 had PNS. The CRAE of the PFS group was significantly lower than that of the PNS group in all glaucoma patients (P = .001). However, neither the mean deviation in VF nor that in the average retinal nerve fiber layer thickness showed significant intergroup differences. In the NTG subgroup analysis, the CRAE of the PFS group was significantly lower than that of the PNS group (P = .013). Conversely, in the POAG subgroup analysis, the CRAE in the PFS group did not differ significantly from that in the PNS group (P = .123).

CONCLUSIONS

Retinal arteriolar diameter was narrower in OAG patients with initial PFS than in those with initial PNS, especially in the NTG group. This suggests that the initial location of the VF defect may be associated with the vascular mechanism in patients with glaucoma.

Ophthalmological Assessment of OCT and Electrophysiological Changes in Migraine Patients

BACKGROUND

A cross-sectional study to investigate the morphological and functional changes of the visual pathway taking place in patients with migraine.

METHODS

Fifteen patients (14 female, 1 male) diagnosed with migraine with aura and 23 patients (21 female, 2 male) diagnosed with migraine without aura were compared with 20 healthy volunteers (18 female, 2 male). All the participants underwent optical coherence tomography scan, electroretinogram (ERG), visual evoked potentials, and multifocal electroretinogram (mf-ERG) recording.

RESULTS

Assessing ERG recordings, no significant differences in mean N1-P1 amplitudes were measured among the groups. The mean visual evoked potentials N80-P100 amplitudes were not significantly different among the three groups (one way analysis of variance: P = 0.075, F = 2.718). No significant difference was found in P100 latency times among groups. The mean retinal response density of mf-ERG in ring 1 was higher in healthy individuals compared with migraineurs, with statistical significance (Kruskal-Wallis analysis of variance and Dunn multiple comparisons test; P < 0.001, mean rank difference = -24.857 and P < 0.001, mean rank difference = -20.9, for migraine with aura-control and migraine without aura-control comparisons, respectively). In migraine with aura subjects, retinal nerve fiber layer thickness in superior and inferior quadrants was significantly decreased compared with healthy individuals, whereas in migraine without aura group, only the superior quadrant was significantly thinner compared with the control group.

CONCLUSIONS

Retinal response density in mfERG of all migraineurs was significantly lessened compared with healthy individuals. There was no significant difference in visual evoked potentials N80-P100 amplitudes or P100 latencies among the groups. Moreover, retinal nerve fiber layer thinning observed in patients with migraine compared with control subjects, appeared statistically significant in some quadrants. The authors may be able to defend the retinal blood flow decrease theory in migraine. The results also indicate that several levels of the visual pathway seem to be affected in migraineurs.

Ocular blood flow in glaucoma - the Leuven Eye Study

PURPOSE

Elevated intra-ocular pressure (IOP) has been identified as a major risk factor for glaucoma. Additionally, extensive literature depicts a vascular dysfunction to exist in these patients. However, a large ocular blood flow-oriented trial to integrate these findings in the clinical setting is lacking. This study would likely help to identify which of these vascular data can be used as a clinical tool for screening and disease stratification.

METHOD

Prospective, cross-sectional, case-control hospital-based study. Patients with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), ocular hypertension (OHT), glaucoma suspects and healthy volunteers were recruited. In addition to a comprehensive ophthalmological examination, a vascular-oriented questionnaire was completed and ocular blood flow assessment (colour Doppler imaging of retrobulbar vessels, retinal oximetry, dynamic contour tonometry, optical coherent tomography enhanced-depth imaging of the choroid) were performed. Statistical analysis was based on multiple imputation to account for missingness.

RESULTS

A total of 614 subjects (291 males) were recruited between March and December 2013 (POAG: 214, NTG: 192; OHT: 27; glaucoma suspect: 41; healthy controls: 140). Glaucoma groups (NTG and POAG) were age and gender matched with the control group (p > 0.05). Glaucoma groups were paired in terms of functional and structural parameters (p > 0.08). Mean ocular perfusion pressure was higher in the glaucoma groups than in controls (p < 0.001). Glaucoma groups had lower retrobulbar velocities, higher retinal venous saturation and choroidal thickness asymmetries when compared to the healthy group, in line with the current literature.

CONCLUSIONS

The Leuven Eye Study stands as one of the largest clinical trials on ocular blood flow in glaucoma. The creation of this vast database may help integrate the vascular aspects of glaucoma into the clinical practice of glaucoma.

Motion Processing Deficits in Migraine

This study was designed to determine whether cortical motion processing abnormalities are present in individuals with migraine. Performance was measured using a visual motion coherence task (motion coherence perimetry, MCP) thought to depend on the operation of cortical area V5. Motion coherence thresholds were measured using stimuli composed of moving dots at 17 locations in the central ± 20° of visual field. Pre-cortical visual function was also measured using frequency doubling perimetry (FDP) at the same 17 locations. Several migraine subjects demonstrated significant pre-cortical visual functional abnormalities, however, most subjects had normal visual fields measured with FDP. Abnormal MCP performance was measured in 15 of 19 migraine-with-aura subjects, and 11 of 17 migraine-without-aura subjects. A decreased ability to detect coherent motion may possibly be explained by an increase in baseline neuronal noise, such as would be consistent with the concept of cortical hyperexcitability in migraine.

Intraocular pressure and ocular biometric parameters changes in migraine

Background

The aim of this study was to assess the intraocular pressure and ocular biometric parameters in migraine patients during acute migraine attacks and compare them with painless period and healthy controls using a new optical biometer AL-Scan.

Methods

In this prospective, case–control study, the axial length, corneal curvature radius, anterior chamber depth, central corneal thickness, and pupil size of 40 migraine patients during acute migraine attacks and painless period and 40 age- and sex-matched healthy subjects were measured using a AL-Scan optical biometer (Nidek Co., Gamagori, Japan). All patients underwent a complete ophthalmic examination before the measurements. IOP and biometer measurements were taken at the same time of day (10:00–12:00) in order to minimize the effects of diurnal variation.

Results

There was not a statistically significant difference in intraocular pressure between the migraine patients during acute migraine attacks (15.07 mmHg), painless period (14.10 mmHg), and the controls (15,73 ± 0,81). Also, the ocular biometric parameters did not significantly vary during the acute migraine attacks.

Conclusions

Further studies are needed to evaluate the etiopathologic relationship between intraocular pressure and ocular biometric parameters and acute migraine attack.

Does Migraine Increase the Risk of Glaucoma?: A Population-Based Cohort Study

This study investigated whether migraine influences the risk of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) in Taiwan.We retrieved the data analyzed in this study from the National Health Insurance Research Database in Taiwan. We included 17,606 newly diagnosed migraine patients without preexisting glaucoma and randomly selected and matched 70,423 subjects without migraine as the comparison cohort. The same exclusion criteria were also applied to comparison subjects. Multivariate Cox proportion-hazards regression model was used to assess the effects of migraines on the risk of glaucoma after adjusting for demographic characteristics and comorbidities.The cumulative incidence of POAG was higher in the migraine cohort than that in the comparison cohort (log-rank P = 0.04). The overall incidence of POAG (per 10,000 person-years) was 9.62 and 7.69, respectively, for migraine cohort and nonmigraine cohort (crude hazard ratio [HR] = 1.24, 95% confidence interval [CI] = 1.01-1.54). After adjusting the covariates, the risk of POAG was not significantly higher in the migraine cohort than in the comparison cohort (adjusted HR [aHR] = 1.15, 95% CI = 0.93-1.42). The cumulative incidence of PACG did not differ between the migraine cohort and the comparison cohort (log-rank test P = 0.53). The overall incidence of PACG was not significantly higher in the migraine cohort than that in the comparison cohort (7.42 vs 6.84 per 10,000 person-years), with an aHR of 1.04 (95% CI = 0.82-1.32).This study shows that migraines are not associated with a higher risk either in POAG or in PACG.

Retinal Nerve Fiber Layer Thickness Changes in Migraine: A Meta-Analysis of Case-Control Studies

BACKGROUND

The neurovascular dysfunction appears to be related to the development of migraines and it could be possible that hypoperfusion might also involve other areas besides brain, including the retina. Numerous studies have analyzed the ability of optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) thickness abnormalities and changes in migraine, but the results have not always been consistent. Therefore, we carried out a meta-analysis to evaluate the RNFL thickness measured with OCT in migraine.

METHODS

Case-control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PUBMED and EMBASE. For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence interval (CI). The statistical analysis was performed by RevMan 5.0 software.

RESULTS

Six case-control studies were included in the present meta-analysis, containing a total of 432 eyes in migraine patients and 288 eyes in healthy controls. The results of our study showed that there was a significant reduction in average RNFL thickness in patients with migraine compared to healthy controls (WMD = -3.67, 95% CI: -6.84 to -0.49, p = 0.02). Additionally, differences of RNFL thickness in superior quadrant (WMD = -9.23, 95% CI: -15.63 to -2.82, p = 0.005), inferior quadrant (WMD = -3.47, 95% CI: -6.73 to -0.22, p = 0.04), nasal quadrant (WMD = -3.86, 95% CI: -7.10 to -0.61, p = 0.02) and temporal quadrant (WMD = -3.10, 95% CI: -5.05 to -1.15, p = 0.002) were all significant between the two groups.

CONCLUSIONS

Our meta-analysis found that RNFL thickness in the migraine patients was thinner than that in the healthy control group. Given the limited sample size, further investigations are needed to validate these findings.

Towards axonal regeneration and neuroprotection in glaucoma: Rho kinase inhibitors as promising therapeutics

Due to a prolonged life expectancy worldwide, the incidence of age-related neurodegenerative disorders such as glaucoma is increasing. Glaucoma is the second cause of blindness, resulting from a slow and progressive loss of retinal ganglion cells (RGCs) and their axons. Up to now, intraocular pressure (IOP) reduction is the only treatment modality by which ophthalmologists attempt to control disease progression. However, not all patients benefit from this therapy, and the pathophysiology of glaucoma is not always associated with an elevated IOP. These limitations, together with the multifactorial etiology of glaucoma, urge the pressing medical need for novel and alternative treatment strategies. Such new therapies should focus on preventing or retarding RGC death, but also on repair of injured axons, to ultimately preserve or improve structural and functional connectivity. In this respect, Rho-associated coiled-coil forming protein kinase (ROCK) inhibitors hold a promising potential to become very prominent drugs for future glaucoma treatment. Their field of action in the eye does not seem to be restricted to IOP reduction by targeting the trabecular meshwork or improving filtration surgery outcome. Indeed, over the past years, important progress has been made in elucidating their ability to improve ocular blood flow, to prevent RGC death/increase RGC survival and to retard axonal degeneration or induce proper axonal regeneration. Within this review, we aim to highlight the currently known capacity of ROCK inhibition to promote neuroprotection and regeneration in several in vitro, ex vivo and in vivo experimental glaucoma models.

Clinical impact of migraine for the management of glaucoma patients

Migraine is a common and debilitating primary headache disorder that affects 10-15% of the general population, particularly people of working age. Migraine is relevant to providers of clinical eye-care because migraine attacks are associated with a range of visual sensory symptoms, and because of growing evidence that the results of standard tests of visual function necessary for the diagnosis and monitoring of glaucoma (visual fields, electrophysiology, ocular imaging) can be abnormal due to migraine. These abnormalities are measureable in-between migraine events (the interictal period), despite patients being asymptomatic and otherwise healthy. This picture is further complicated by epidemiological data that suggests an increased prevalence of migraine in patients with glaucoma, particularly in patients with normal tension glaucoma. We discuss how migraine, as a co-morbidity, can confound the results and interpretation of clinical tests that form part of contemporary glaucoma evaluation, and provide practical evidence-based recommendations for the clinical testing and management of patients with migraine who attend eye-care settings.

Choroid thickness and ocular pulse amplitude in migraine during attack

AIM

To compare the choroidal thickness and ocular pulse amplitude (OPA) measurements obtained during the attack period in migraine patients and age and gender matched control group participants using high definition optical coherence tomography (OCT).

METHODS

Thirty eyes at the side of the headache of 30 subjects with a diagnosis of migraine with or without aura and unilateral migraine and 29 age and gender matched healthy participants were enrolled in this observational, cross-sectional study. OCT scans were performed to all participants. Choroidal thicknesses were measured at the fovea, 1500 μm nasal and 1500 μm temporal to the fovea. Intraocular pressure (IOP) and OPA were also measured.

RESULTS

The choroidal thickness measurements obtained during the attack period in migraine patients were (mean±SD) 279.82±35.87, 250.05±29.49, and 239.58±27.92 and in control group were 308.20±44.97, 276.95±41.39, and 281.60±41.38 at foveal, nasal, and temporal measurement points, respectively. Choroidal thickness significantly decreased according to the control group (P<0.05) at all measured points in migraine patients during attack. IOP (mean±SD) values were 16.71±3.26 and17.40±3.19 and OPA (mean±SD) values were 2.26±0.81 and 2.64±1.03 in migraine and control groups, respectively, and did not seem to be changed (P>0.05).

CONCLUSIONS

Choroidal thickness was found to be significantly decreased in unilateral migraine patients during the attack period when compared with the control group, whereas OPA did not change. The possible implications of these findings on the association between migraine and glaucoma are discussed.

Vascular dysregulation in normal-tension glaucoma is not affected by structure and function of the microcirculation or macrocirculation at rest: a case-control study

In normal-tension glaucoma (NTG), optic nerve damage occurs despite a normal intraocular pressure. Studies implicating systemic blood pressure or, more recently, arterial stiffness in the pathophysiology of NTG have produced conflicting results. Our aim was to investigate whether NTG is associated with alterations in the macrocirculation or microcirculation, cardiac function, and peripheral and central hemodynamics. Thirty patients with NTG (mean age 65 years, range 46-79) and 33 healthy subjects (mean age 67 years, range 42-79) matched for age and sex were included in the study. Exclusion criteria (for both cases and controls) were history of cardiovascular disease, diabetes mellitus, severe hypertension, and hypercholesterolemia. Aortic stiffness was measured using carotid-femoral pulse wave velocity (PWV), central hemodynamics using carotid artery applanation tonometry, and diameter, stiffness, and intima-media thickness (IMT) of the carotid and femoral artery using echo-tracking. Total peripheral resistance index (TPRI) was derived from mean arterial pressure and cardiac index, measured using ultrasound. There were no statistically significant differences in arterial structure nor function between NTG patients and age and sex-matched controls. NTG versus controls, respectively: brachial blood pressure 126 ± 15/77 ± 8 versus 127 ± 16/76 ± 7 mm Hg, P = 0.81; carotid-femoral PWV 9.8 ± 2.1 versus 10.1 ± 1.9 m/s, P = 0.60; TPRI 1833 ± 609 versus 1779 ± 602 dyne.s/cm5/m2, P = 0.79; and carotid IMT 0.65 ± 0.14 versus 0.68 ± 0.13 mm, P = 0.39. This study could not show an association of NTG with altered IMT, arterial stiffness, total peripheral resistance, cardiac output, and peripheral or central hemodynamics at rest. Although the majority of these NTG patients do exhibit symptoms of vascular dysregulation, in the present study this was not translated into alterations in the microcirculation or macrocirculation at rest.

Retinal vessel diameter in normal-tension glaucoma patients with asymmetric progression

PURPOSE

To investigate the longitudinal changes in the central retinal vessel diameter in asymmetric progressive normal-tension glaucoma (NTG) patients.

METHODS

This study included 27 patients with bilateral NTG without any systemic vascular disease who showed glaucomatous progression in one eye at the mean follow-up of 24.3 months (range, 18-29 months). Progression was determined by the development of new retinal nerve fiber layer (RNFL) defects or widening of pre-existing defects on red-free RNFL photographs. The central retinal arteriolar equivalent (CRAE) and the central retinal venular equivalent (CRVE) were measured at baseline and at the mean follow-up of 24.3 months. We classified the eyes of each patient as either progressed or stable eyes, and compared the differences and changes in the CRAE and CRVE.

RESULTS

No significant inter-eye difference was observed at baseline in the mean CRAE (167.5 ± 22.2 μm vs. 168.2 ± 15.5 μm, p = 0.809) and in the mean CRVE (276.3 ± 18.2 μm vs. 281.6 ± 21.9 μm, p = 0.267) between the progressed and stable eyes. There were significant changes in CRAE in the progressed eyes between baseline and 2 years after baseline (from 167.5 ± 22.2 μm to 146.9 ± 18.0 μm, p < 0.0001), but there were no significant changes in the stable eyes (from 168.2 ± 15.5 μm to 167.5 ± 14.8 μm, p = 0.084).

CONCLUSIONS

In our series of NTG patients with asymmetric progression, central retinal artery diameter decreased over time in the progressed eyes, whereas no significant decrease in the central retinal artery diameter was seen in the stable eyes.

Ocular pulse amplitude and Doppler waveform analysis in glaucoma patients

PURPOSE

To determine the correlation between ocular blood flow velocities and ocular pulse amplitude (OPA) in glaucoma patients using colour Doppler imaging (CDI) waveform analysis.

METHOD

A prospective, observer-masked, case-control study was performed. OPA and blood flow variables from central retinal artery and vein (CRA, CRV), nasal and temporal short posterior ciliary arteries (NPCA, TPCA) and ophthalmic artery (OA) were obtained through dynamic contour tonometry and CDI, respectively. Univariate and multiple regression analyses were performed to explore the correlations between OPA and retrobulbar CDI waveform and systemic cardiovascular parameters (blood pressure, blood pressure amplitude, mean ocular perfusion pressure and peripheral pulse).

RESULTS

One hundred and ninety-two patients were included [healthy controls: 55; primary open-angle glaucoma (POAG): 74; normal-tension glaucoma (NTG): 63]. OPA was statistically different between groups (Healthy: 3.17 ± 1.2 mmHg; NTG: 2.58 ± 1.2 mmHg; POAG: 2.60 ± 1.1 mmHg; p < 0.01), but not between the glaucoma groups (p = 0.60). Multiple regression models to explain OPA variance were made for each cohort (healthy: p < 0.001, r = 0.605; NTG: p = 0.003, r = 0.372; POAG: p < 0.001, r = 0.412). OPA was independently associated with retrobulbar CDI parameters in the healthy subjects and POAG patients (healthy CRV resistance index: β = 3.37, CI: 0.16-6.59; healthy NPCA mean systolic/diastolic velocity ratio: β = 1.34, CI: 0.52-2.15; POAG TPCA mean systolic velocity: β = 0.14, CI 0.05-0.23). OPA in the NTG group was associated with diastolic blood pressure and pulse rate (β = -0.04, CI: -0.06 to -0.01; β = -0.04, CI: -0.06 to -0.001, respectively).

CONCLUSIONS

Vascular-related models provide a better explanation to OPA variance in healthy individuals than in glaucoma patients. The variables that influence OPA seem to be different in healthy, POAG and NTG patients.

Retinal nerve fibre layer, ganglion cell layer and choroid thinning in migraine with aura

BACKGROUND

The aim of this study was to investigate the thickness of the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), and choroid thickness (CT) in patients who have migraines, with and without aura, using spectral optical coherence tomography (OCT).

METHODS

Forty-five patients who had migraines without aura (Group 1), 45 patients who had migraines with aura (Group 2), and 30 healthy participants (control group) were included in the study. Spectral OCT was used to measure the RNFL, GCL and CT values for all patients.

RESULTS

The mean age of Group 1, Group 2, and the control group was 34.6 ± 4.3, 32.8 ± 4.9, and 31.8 ± 4.6 years, respectively. The mean attack frequency was 3.6/month in Group 1 and 3.7/month in Group 2. The mean age among the groups (p = 0.27) and number of attacks in migraine patients (p = 0.73) were not significantly different. There was significant thinning in the RNFL and GCL in Group 2 (p < 0.05, p < 0.001 respectively), while there were no significant differences in RNFL and GCL measurements between Group 1 and the control group (p > 0.05). All groups were significantly different from one another with respect to CT, with the most thinning observed in Group 2 (p < 0.001). When all migraine patients (without grouping) were compared with the control group, there were significant differences on all parameters: RNFL thickness, GCC thickness and CT (p < 0.05).

CONCLUSIONS

RNFL and GCL were significantly thinner in the migraine patients with aura as compared with both the migraine patients without aura and the control subjects. In migraine, both with aura and without aura, patients' choroid thinning should be considered when evaluating ophthalmological findings.