Association Between Platelet Function and Disc Hemorrhage in Patients With Normal-Tension Glaucoma: A Prospective Cross-Sectional Study

Pharmaceutical Approaches to Normal Tension Glaucoma

Normal tension glaucoma (NTG) is defined as a subtype of primary open-angle glaucoma (POAG) in which the intraocular pressure (IOP) values are constantly within the statistically normal range without treatment and represents approximately the 30-40% of all glaucomatous cases. The pathophysiology of this condition is multifactorial and is still not completely well known. Several theories have been proposed to explain the onset and progression of this disease, which can be divided into IOP-dependent and IOP-independent factors, suggesting different therapeutic strategies. The current literature strongly supports the fundamental role of IOP in NTG. The gold standard treatment for NTG tends to be based on the lowering IOP even if "statistically normal". Numerous studies have shown, however, that the IOP reduction alone is not enough to slow down or stop the disease progression in all cases, suggesting that other IOP-independent risk factors may contribute to the NTG pathogenesis. In addition to IOP-lowering strategies, several different therapeutic approaches for NTG have been proposed, based on vaso-active, antioxidant, anti-inflammatory and/or neuroprotective substances. To date, unfortunately, there are no standardized or proven treatment alternatives for NTG when compared to traditional IOP reduction treatment regimes. The efficacy of the IOP-independent strategies in decreasing the risk or treating NTG still remains inconclusive. The aim of this review is to highlight strategies reported in the current literature to treat NTG. The paper also describes the challenges in finding appropriate and pertinent treatments for this potentially vision-threatening disease. Further comprehension of NTG pathophysiology can help clinicians determine when to use IOP-lowering treatments alone and when to consider additional or alternatively individualized therapies focused on particular risk factors, on a case-by-case basis.

Optical Coherence Tomography Angiography Demonstrates Strain and Volume Effects on Optic Disk and Peripapillary Vasculature Caused by Horizontal Duction

PURPOSE

The optic nerve mechanically loads the eye during ocular rotation, thus altering the configuration of the disk and peripapillary tissues. We used optical coherence tomography (OCT) angiography (OCTA) to investigate mechanical strains and volume changes in disk and peripapillary blood vessels during horizontal duction.

METHODS

Structural OCT and OCTA were performed centered on optic disks; imaging was repeated in central gaze, and in 30° ab- and adduction. By an algorithm employing point-set registration of 3 D features, we developed a novel approach for measuring disk strains, and strains and volumes of the blood vessels associated with horizontal duction. Repeatability was demonstrated in each gaze position.

RESULTS

19 eyes of 10 healthy adults of average age 37 ± 15 (standard deviation, SD) years were imaged. The method was validated by demonstrating numerically consistent vascular volumes and strains for repeated imaging under identical conditions. Compared with central gaze, vascular volume increased by 5.2 ± 4.1% in adduction. Adduction and abduction caused strains of 3.0 ± 1.6% and 2.6 ± 1.8% in the optic disk, whereas blood vessels showed greater strains of 8.1 ± 1.3% and 8.2 ± 1.7%. Decomposition of strain components depending on directionality and regions demonstrated that adduction induces significant net tensile strains, suggesting traction exerted by the optic nerve. The decomposition also showed that nasotemporal compressive strains are larger in temporal hemidisks than nasal hemidisks. The Bruch's membrane opening was significantly compressed horizontally in adduction by 1.1% (p = .009).

CONCLUSION

This novel analysis combining structural OCT and OCTA demonstrates that optic disk compression during adduction is associated with disk and vascular strains much larger than reported for intraocular pressure elevation and pulsatile perfusion, as well as compressing the disk and increasing peripapillary vascular volume. These changes may be relevant to the pathogenesis of optic nerve and retinal vascular disorders.

Analysis of Variation in Incidence of Optic Disc Hemorrhage According to Seasonal and Temperature Changes

PURPOSE

To investigate seasonal variation in optic disc hemorrhage (DH) by review of fundus photographs representative of 2 calendar years (2019 and 2020).

DESIGN

Retrospective, observational trend study.

METHODS

Patients who visited the Glaucoma Clinic of Seoul National University Hospital and underwent fundus photography were included. All available stereo disc photographs and red-free retinal nerve fiber layer photographs taken between January 1, 2019 and December 31, 2020 were retrospectively reviewed. The monthly incidence rate of DH was determined by reference to the photographs. Seasonal temperature information and patients' intraocular pressure (IOP) information were obtained, organized, and analyzed.

RESULTS

Fundus images of 13,514 eyes were reviewed, and 454 eyes were confirmed to have DH. Poisson regression analyses revealed that as the temperature (T) increased by 1 °C, the DH risk ratio was reduced to 0.979 (95% confidence interval [CI] 0.969-0.989, P < .01). The DH incidence ratio was 1.53 (95% CI 1.23-1.91, P < .01) for the T <10 °C group relative to the T ≥20 °C group. The IOP of the patients with DH in winter was significantly higher than that measured in summer.

CONCLUSION

DH is affected by temperature, and as such, shows seasonal variability. This variability is believed to be caused by temperature-related factors such as IOP or hematological factors. © 2022 Elsevier Inc. All rights reserved.

Primary Open-Angle Glaucoma Combined With Concomitant Somatic Pathology

The goal of the study was to assess the role of concomitant somatic pathology and calculate the total comorbidity index of primary open-angle glaucoma (POAG) in different age groups. Material and Methods — The study included 624 patients (1199 eyes) with POAG aged 45 to 93 years. The control group included 161 people without glaucoma. Patients underwent a comprehensive ophthalmological examination. The Charlson comorbidity index (CI) was calculated, taking into account the concomitant somatic diseases and the age of the patients. Statistical processing of the obtained material was carried out using the IBM SPSS Statistics v.21 program with standard methods of descriptive statistics. Results — with an increase in the age of POAG patients, significant growth in the number of patients with hypertension, coronary heart disease, cerebrovascular accident, atherosclerosis, degenerative diseases of the nervous system, diabetes mellitus, respiratory diseases, musculoskeletal system, and other pathologies were observed. CI was increased in POAG patients with age: 3.02 times for the old age patients, 4.2 times for very old age subjects, compared with middle-aged patients (p<0.001), as well as 1.42 and 1.97 times, respectively, compared with the control group (p<0.001). Conclusion —In patients with POAG, the number of patients with hypertension, ischemic heart disease, cerebrovascular disorders, atherosclerosis, degenerative diseases of the nervous system, diabetes mellitus, respiratory diseases, musculoskeletal system disorders, and other pathologies increased significantly with age. The comorbidity index in POAG patients exhibited growth with age: 3.02 times in the old age group and 4.2 times in the group of very old age people vs. the group of middle-aged patients (p<0.001); and 1.42 and 1.97 times, respectively, vs. the control group (p<0.001).

Effect of systemic blood pressure on optical coherence tomography angiography in glaucoma patients

BACKGROUND

The association between retinal microvascular structure and glaucoma has been revealed in multiple studies using optical tomography angiography (OCTA), but limited information on the macular vessel density (mVD) in patients with glaucoma is available. In this study, we tried to identity the factors that affected macular VD (mVD) in glaucomatous eyes.

METHODS

This retrospective cross-sectional study evaluated OCT and OCTA images from 92 eyes from 58 healthy subjects and 179 eyes from 103 glaucoma patients using the SD-OCT database from July 2017 to July 2018. Glaucomatous eyes were further divided into two groups according to history of disc haemorrhage (DH). Association between mVD and demographic characteristics, ganglion cell-inner plexiform layer (GCIPL) thickness, visual field mean deviation (MD) and systemic blood pressure was analysed in each group.

RESULTS

In both healthy and glaucomatous eyes, mVD was inversely associated with age (β = -0.035, P = 0.025; β = -0.039, P = 0.018). In the glaucomatous eyes, mVD was significantly decreased, as the MD value was worse (β = 0.109, P = 0.002). In glaucomatous eyes with DH, mVD decreased as blood pressure increased (β = -0.111, P = 0.003) CONCLUSIONS: Reduced mVD is more common in older individuals in both healthy and glaucomatous eyes, and correlates with functional deterioration than structural damage in glaucomatous eyes. In glaucomatous eyes with DH, high systemic BP is associated with a reduction in mVD. This may indicate that glaucoma patients with DH are more susceptible to vascular damage secondary to hypertension.

Evidence-based understanding of disc hemorrhage in glaucoma

Disc hemorrhage is a characteristic finding that is highly associated with glaucoma development or progression. Consequently, the literature commonly designates disc hemorrhage as a "risk factor" for glaucoma progression; however, the exact cause-and-effect relationship or mechanism remains unclear. In this review, we discuss the emerging evidence that disc hemorrhage is a secondary development that follows glaucomatous damage. As our understanding of disc hemorrhage has progressed in recent decades, we suggest the terminology be changed from "risk factor" to "indicator" of ongoing glaucomatous development or progression for a more accurate description, better indication of the clinical implications and, ultimately, a better guide for future research.

Development of a nomogram using fundus photography to predict glaucoma progression in patients showing disc hemorrhage

To develop a nomogram to predict the progression of glaucoma by fundus photography in patients with disc hemorrhage. Retrospective review of the medical records of patients with disc hemorrhage, which was detected during follow up with open angle glaucoma, from January 2010 to March 2018. Patients were divided into glaucoma progression (n = 52) or non-progression (n = 38) groups. We assessed proximal location and morphology of disc hemorrhage; relationship to retinal nerve fiber layer defects with disc hemorrhage; and angular extent of disc hemorrhage, between groups using fundus photography. Multiple logistic regression analysis was performed to select prognostic factors, and we constructed a nomogram to predict glaucoma progression. The number of disc hemorrhage at the border of retinal nerve fiber layer defects (P = 0.001) and peripapillary disc hemorrhage (P = 0.008) were significantly higher in the progression group. We used angular extent; location of disc hemorrhage with retinal nerve fiber layer defects; and proximal location of disc hemorrhage to construct the nomogram. The area under the receiver operating characteristic curve of the nomogram was 0.847. We created the nomogram using fundus photography in patients showing disc hemorrhage as a novel and accurate screening method to predict glaucoma progression and aid clinicians to decide on the best treatment plan.

Comparison of Peripapillary Capillary Density in Glaucoma Patients of African and European Descent

PURPOSE

To evaluate racial differences in optic nerve head peripapillary capillary density measured by OCT angiography (OCTA) in patients with open-angle glaucoma.

DESIGN

Observational, cross-sectional study.

PARTICIPANTS

Two hundred eighty-four eyes of 195 glaucoma patients and 108 eyes of 58 healthy participants from the Diagnostic Innovations in Glaucoma Study.

METHODS

Global and sectoral circumpapillary capillary density (cpCD) loss in participants of European descent (ED) and African descent (AD) were compared. Areas under the receiver operating characteristic curve (AUROCs) were used to evaluate diagnostic accuracy of cpCD and global circumpapillary retinal nerve fiber layer (cpRNFL) thickness in the 2 groups after adjusting for confounders.

MAIN OUTCOME MEASURES

Peripapillary capillary density and cpRNFL thickness measurements and their estimated loss.

RESULTS

Participants of AD and ED with glaucoma were of similar age and glaucoma severity. After adjusting for age, disc area, and other confounders, significantly lower cpCD was found in ED eyes compared with AD eyes in mild glaucoma (mean, 42.2% [95% confidence interval (CI), 41.2%-43.2%] and 46.5% [95% CI, 44.8%-48.1%], respectively; adjusted difference, 4.4 [95% CI, 2.6-6.2]; P < 0.001) and moderate to advanced glaucoma (mean, 34.7% and 38.5%, respectively; adjusted difference, 4.8 [95% CI, 1.6-8.1]; P = 0.005). Although capillary density loss was greater in all sectors in ED compared with AD participants, a similar sectoral pattern of density loss was observed in both racial groups. Lower mean deviation and older age were associated with lower cpCD in both races in multivariate models. The adjusted AUROC for discriminating between healthy and glaucomatous eyes for cpCD was higher for ED (0.95) compared with AD (0.68) patients (P < 0.001). Sensitivity at 95% specificity in AD participants was lower than in ED participants for cpCD (0.32 [95% CI, 0.11-0.64] vs. 0.83 [95% CI, 0.69-0.93], respectively; P < 0.001).

CONCLUSIONS

Although peripapillary capillary density parameters showed good diagnostic accuracy for detecting glaucoma in ED patients, their diagnostic accuracy was only modest in AD patients. Diagnostic performance of cpCD is race dependent, and clinicians should be aware that it has poorer performance in AD patients.

Nailfold Capillary Hemorrhages: Microvascular Risk Factors for Primary Open-Angle Glaucoma

Background

Primary open-angle glaucoma (POAG) is associated with systemic microvascular dysfunction including hemorrhages and other abnormalities of the nailfold capillary bed. This study aimed to verify the specificity of nailfold capillary hemorrhages and other abnormalities as risk factors for POAG.

Methods

Nailfold video capillaroscopy was performed using a JH-1004 capillaroscope on the fourth and fifth digits of the nondominant hand in control (n = 277), POAG (n = 206), OHT (n = 57), and SG (n = 29) subjects. The number of hemorrhages, dilated capillaries >50 µm, and avascular zones ≥200 µm were counted and adjusted to counts per 100 capillaries. Descriptive analyses as well as univariate- and multivariable-adjusted logistic regression were performed comparing all groups with controls and POAG with OHT and SG. Subanalyses were conducted in POAG patients examining the association between nailfold capillary outcomes and previous glaucoma surgery, successful IOP control, or disease severity.

Results

All nailfold capillary outcomes were significantly increased in POAG, no outcomes were increased in SG, and only hemorrhages were mildly increased in OHT. Hemorrhages were significantly more frequent in POAG compared with both OHT (P < 0.0001) and SG (P=0.001). There were significant trends between higher numbers of hemorrhages and POAG compared with controls, OHT, and SG, with odds ratios of 18.3 (8.5-39.4), 9.1 (1.9-13.4), and 11.8 (1.7-7.3), respectively, for the presence of two or more hemorrhages per 100 capillaries. Hemorrhages were not significantly associated with previous glaucoma surgery, successful postoperative IOP control, or disease severity in POAG.

Conclusions

These findings suggest that systemic microvascular dysfunction is frequent in POAG and occurs early in the disease process. The high specificity of nailfold hemorrhages makes them viable clinical risk factors for POAG.

Choroidal Microvascular Dropout in Primary Open-angle Glaucoma Eyes With Disc Hemorrhage

PURPOSE

The main purpose of this study was to compare the prevalence of choroidal microvascular dropout (CMvD) in primary open-angle glaucoma (POAG) eyes with and without disc hemorrhage (DH).

METHODS

In a cross-sectional study, 44 eyes of 44 control subjects, 32 eyes of 32 POAG patients with DH, and 41 eyes of 41 POAG patients without DH underwent visual fields (VFs), optical coherence tomography (OCT) and OCT angiography (OCTA). Presence of CMvD was evaluated on the choroidal OCTA slab. VF defect in the glaucoma eyes were classified into initial nasal defect, initial parafoveal scotoma, and combined nasal and parafoveal defect.

RESULTS

CMvD was detected in 17 POAG eyes with DH (53.1%) and 13 POAG eyes without DH (31.7%; P=0.06). On univariate analysis, CMvD in POAG eyes was associated with DH [odds ratio (OR): 2.44, P=0.06] and measures of glaucoma severity: VF mean deviation (OR: 0.85, P=0.02), retinal nerve fiber layer thickness (OR: 0.95, P=0.03), and peripapillary vessel density (OR: 0.94, P=0.09). On multivariate models that accounted for the measures of glaucoma severity, CMvD in POAG eyes was statistically significantly associated with DH (OR≥3, P<0.05). CMvD was more frequently seen in eyes with initial parafoveal scotoma than initial nasal defect both in POAG eyes with DH (P=0.06) and POAG eyes without DH (P<0.001).

CONCLUSIONS

Prevalence of CMvD was significantly greater in POAG eyes with DH compared with POAG eyes without DH. CMvD in POAG eyes was also significantly associated with central VF defects and greater severity of glaucomatous damage.

Effect of Antiplatelet/Anticoagulant Use on Glaucoma Progression in Eyes With Optic Disc Hemorrhage

PURPOSE

To assess whether the use of antiplatelets (APs)/anticoagulants (ACs) affects glaucoma progression in eyes with optic disc hemorrhage (DH).

METHODS

One hundred and nineteen eyes from 119 patients with primary open-angle glaucoma in whom a DH was observed at least once during the follow-up period (mean follow-up duration: 6.2 y) were included in this retrospective observational study. Cox proportional hazard models were used to identify the association between putative factors, including AP/AC use, and glaucoma progression. Glaucoma progression was assessed on the basis of changes noted on serial optic disc and retinal nerve fiber layer photographs or changes in the visual field.

RESULTS

Nineteen of the 119 patients took AP/AC drugs daily [AP/AC use group (AG)], while the others did not [no use group (NG)]. The follow-up period to progression was significantly different between the 2 groups (61.2±23.5 mo for the AG and 47.6±22.0 mo for the NG; P=0.016). Kaplan-Meier analysis revealed a greater cumulative probability of glaucoma progression in the NG than in the AG, with borderline statistical significance (P=0.081). Higher mean intraocular pressure during the follow-up period was a risk factor for glaucoma progression (hazard ratio, 1.107; P=0.014), while AP/AC drug use protected against glaucoma progression (hazard ratio, 0.576; P=0.046).

CONCLUSIONS

According to our result, use of AP/AC drugs was associated with lower risk of glaucoma progression in eyes with DH.

Ocular and systemic risk factors associated with recurrent disc hemorrhage in primary open-angle glaucoma

PURPOSE

To evaluate the risk factors associated with recurrent disc hemorrhage (DH), defined for the present study as at least 3 occurrences of DH in primary open-angle glaucoma (POAG).

METHODS

A total of 178 POAG patients (89 eyes showing at least 3 occurrences of DH and 89 age-matched control eyes with a minimum of 10 years' follow-up without DH) were included in a retrospective, case-control study. Ocular factors were evaluated by a retrospective chart review, and systemic factors were evaluated by a telephone survey. Associations between factors and recurrent DH were investigated by logistic regression analysis. The Kaplan-Meier survival analysis and Cox proportional-hazards regression models were used to evaluate glaucoma progression and to identify the factors predictive of glaucoma progression.

RESULTS

Univariate regression analysis revealed the association of recurrent DH with low baseline intraocular pressure (IOP) [odds ratio (OR), 0.88; 95% confidential interval (CI), 0.80-0.98; P = 0.014], lower percentage reduction of IOP (OR, 0.96; 95% CI, 0.93-0.99; P = 0.020), cold extremities (OR, 2.80; 95% CI, 1.03-7.60; P = 0.043), prone or lateral decubitus sleeping position (OR, 2.14; 95% CI, 1.13-4.03; P = 0.019), and sleeping disorders (OR, 2.33; 95% CI, 1.05-5.15; P = 0.037). Multivariate regression analysis revealed that a lower percentage reduction in IOP (OR, 0.96; 95% CI, 0.93-1.00; P = 0.046) increased the risk of recurrent DH. The control group exhibited a greater cumulative probability of non-progression than the recurrent DH group (P = 0.01, by log-rank test). The Cox proportional-hazards regression model showed that recurrent DH was associated with glaucoma progression [hazard ratio (HR), 1.88; 95% CI; 1.66-3.05; P = 0.01.

CONCLUSIONS

Among the ocular and systemic factors, only lower-percentage reduction of IOP in POAG was associated with recurrent DH. DH recurrence is associated with glaucoma progression and may be dependent on IOP.

Hyperlipidemia, Blood Lipid Level, and the Risk of Glaucoma: A Meta-Analysis

Purpose

Previous studies reported that hyperlipidemia and blood lipid levels were associated with glaucoma, ocular hypertension (OHT), and intraocular pressure (IOP). However, studies aimed at investigating this association have yielded conflicting results. Therefore, to shed light on these inconclusive findings, we performed multiple distinct meta-analyses to clarify the association of hyperlipidemia and blood lipid levels with glaucoma, OHT, and IOP.

Methods

A systematic literature search from Embase, Web of Science, and PubMed was performed to identify relevant studies. To assess the association between hyperlipidemia and glaucoma, we used the pooled odds ratio (OR) with 95% confidence interval (CI). When we assessed the association between blood lipid levels and IOP levels, the pooled mean difference in IOP associated with a 10 mg/dL increase in the blood lipid level was estimated. The pooled difference in IOP was also estimated between patients with and without hyperlipidemia. All the papers that assessed the correlation between hyperlipidemia and glaucoma, between blood lipid levels and IOP levels, and between hyperlipidemia and IOP were included in this meta-analysis.

Results

We detected a marked association between hyperlipidemia and glaucoma (OR = 1.37; 95% CI = 1.16-1.61), with significant heterogeneity among studies. However, hyperlipidemia was not significantly associated with glaucoma in our analysis of only cross-sectional studies, studies that reported only on hypercholesterolemia patients, studies that were conducted only in North America and Europe, or studies in which normal-tension glaucoma (NTG) patients were included only in the subgroup analyses. The pooled results showed that an increase of 10 mg/dL in blood triglyceride levels would increase the IOP by 0.016 mm Hg (95% CI = 0.009-0.024), with evident heterogeneity between studies (P < 0.001; I2 = 92.0%). The pooled results showed that the blood total cholesterol and low-density lipoprotein-cholesterol (LDL-c) level both had a significant association with IOP. When compared to the patients with nonhyperlipidemia, those with hyperlipidemia had a significantly higher IOP of 0.51 mm Hg (95% CI = 0.18-0.83) (P = 0.001 for heterogeneity; I2 = 81.6%).

Conclusions

The evidence suggests that hyperlipidemia is significantly associated with an increased risk of glaucoma and that hyperlipidemia and the increased blood lipid levels are associated with increased IOP.

Optic disk hemorrhage and vitreous hemorrhage after phacoemulsification in a normal tension glaucoma patient: A case report

RATIONALE

Optic disk hemorrhage has been closely correlated with glaucoma for its development and progression. Phacoemulsification surgery results in large intraocular pressure (IOP) fluctuation. We report a case of optic disk hemorrhage and consequently progressive vitreous hemorrhage after an unsuccessful phacoemulsification surgery in an advanced normal tension glaucoma (NTG) patient.

PATIENT CONCERNS

An advanced NTG patient of 82 years old with chronic hypertension underwent an unsuccessful phacoemulsification surgery complicated by posterior capsule rupture. During the postoperative 2 weeks, recurrent episodes of fresh hyphema occurred and B ultrasonography scan revealed the progressive vitreous hemorrhage. The IOP went out of control under the maximum tolerable IOP-lowering medications.

DIAGNOSIS

Vitreous hemorrhage after phacoemulsification in an advanced NTG patient.

INTERVENTIONS

Vitrectomy was performed to search for the cause of the progressive vitreous hemorrhage. After removal of the thick vitreous hemorrhage, a fresh spot of optic disk hemorrhage was detected at the nasal margin of the significantly-cupping disk.

OUTCOMES

Postoperatively, the hemorrhagic vitreous opacity gradually resolved and the IOP remained stable at 10 ∼13 mmHg with topical prostaglandin analogue drops. Fundus examination revealed the dilated disk vessel with localized angiomatous change at the nasal disk margin.

LESSONS

Severe optic disk hemorrhage may occur after phacoemulsification in advanced glaucoma patients. Systemic vascular factors, such as chronic hypertension and old age, and surgical complications, such as posterior capsule rupture and postoperative IOP elevation, would further increase the risk. For phacoemulsification in advanced glaucoma cases, extra care should be taken to control intraoperative IOP fluctuations and monitor postoperative IOP.

Association between focal lamina cribrosa defects and optic disc haemorrhage in glaucoma

BACKGROUND/AIMS

To explore the relationship between focal lamina defect (LD) size and optic disc haemorrhages (DH) in glaucomatous eyes.

METHODS

Radial B-scan images at 15° intervals obtained using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (OCT) were performed on a group of subjects previously assessed for DH every 3 months over a period of 5 years. EDI-OCT scans were assessed for the presence of focal lamina cribrosa defects by a single observer.

RESULTS

119 eyes from 62 subjects (44 females, 18 males) were analysed. 44 eyes (37%) were noted to have at least 1 LD, and of those, eight eyes had more than one defect. 68 eyes (57%) were observed to have at least one DH occur over the course of monitoring. 48 eyes (40%) had recurrent DH, with a mean of 5.17 haemorrhages over the 5-year period. Type 1 focal LD (p=0.0000, OR 7.17), glaucoma progression (p=0.0024, OR 0.32) and ArtDiff (p=0.0466, OR 1.04) were significantly associated as predictors of DH. No correlation between the size of the LD and DH occurrence (p=0.6449, Spearman rank correlation) was found.

CONCLUSION

Focal lamina cribrosa hole-type defects were significantly associated with an increase in DH occurrence over the preceding 5 years. The lack of association between defect size and DH suggests that DH and lamina defects may have separate links to the glaucomatous process.

The impact of disc hemorrhage studies on our understanding of glaucoma: a systematic review 50 years after the rediscovery of disc hemorrhage

PURPOSE OF REVIEW

To trace the influence of disc hemorrhage studies on our understanding of glaucoma.

SOURCES

Major articles published during the last 50 years since the rediscovery of disc hemorrhage were identified. A total of 196 articles were selected from 435 articles retrieved using the keywords glaucoma and disc hemorrhage as of August 9 2018 from PubMed.

RECENT FINDINGS

The main characteristics of disc hemorrhage, including its morphology, recurrence rate, duration, increased incidence in glaucoma, and role in the progression of normal tension glaucoma was well understood by the year 2000. Since then, studies have focused on more sophisticated and accurate methods of elucidating both structural and functional progression, with special attention to the role of the lamina cribrosa. Nevertheless, both the mechanism of disc hemorrhage development and its fuller relationship with glaucoma remain unclear. Disc hemorrhage research requires careful study of glaucomatous optic neuropathy. This has been facilitated by recent advances in optical coherence tomography (OCT) angiography and other OCT technologies. Furthermore, animal studies of disc hemorrhage promise new insights into glaucomatous optic neuropathy.

Association between Rates of Retinal Nerve Fiber Layer Thinning and Previous Disc Hemorrhage in Glaucoma

PURPOSE

To investigate the relationship between previous disc hemorrhage (DH) and subsequent rates of retinal nerve fiber layer (RNFL) thinning.

DESIGN

Longitudinal, observational cohort study.

PARTICIPANTS

Twenty-eight patients with glaucoma and patients with suspected glaucoma who had a history of DH in 1 eye (unilateral DH), but not in the fellow eye, enrolled in the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study were included.

METHODS

All subjects underwent annual optic disc photography and semiannual spectral-domain OCT RNFL thickness measurements. Multivariable linear mixed-effects models were used to investigate the relationship between the presence of previous DH and RNFL thinning rates while adjusting for potential confounding factors, such as race, age, mean intraocular pressure (IOP), baseline disease severity, and central corneal thickness (CCT). The relationship between the timing of DH and the rates of RNFL thinning also was investigated in eyes with a history of DH.

MAIN OUTCOME MEASURES

Rates of global and local RNFL thinning.

RESULTS

Previous DH was significantly associated with faster RNFL thinning rates globally (-0.39 μm/year faster, P = 0.010), in DH quadrants (-0.77 μm/year faster, P = 0.012), and non-DH quadrants (-0.49 μm/year faster, P = 0.038) after adjustment for race, mean IOP, baseline age, baseline standard automated perimetry mean deviation, and CCT. Higher IOP was also significantly associated with faster thinning rates globally (-0.07 μm/year faster per 1 mmHg higher, P = 0.047) and in DH quadrants (-0.10 μm/year faster per 1 mmHg higher, P = 0.044). In eyes with a history of DH, the time elapsed from the latest DH episode to the first OCT examination was not significantly associated with the rate of RNFL thinning.

CONCLUSIONS

A history of DH is an independent risk factor for faster rates of RNFL thinning in non-DH quadrants and in DH quadrants; this risk is present even in eyes that exhibited DH several years earlier.

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 Between Optic Disc Hemorrhage and Renal Function in South Korea

PURPOSE

The purpose of this article is to investigate the relationship between renal function and disc hemorrhage (DH).

MATERIALS AND METHODS

This retrospective cross-sectional survey was conducted at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013, and a total of 168,044 participants at least 20 years of age who voluntarily visited the health screening center for systemic and ophthalmologic examinations, including fundus photography, were enrolled. All subjects underwent a physical examination and provided samples for laboratory analysis. Digital fundus photographs of both eyes were taken and reviewed. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine concentration using the Modification of Diet in Renal Disease (MDRD) formula and Cockcroft-Gault (CG) formula. Subjects were stratified by eGFR into quartiles.

RESULTS

Among participants, 220 (0.1%) showed DH, and 2376 (1.6%) showed glaucomatous retinal nerve fiber layer defects. The DH group showed higher creatinine and lower eGFR than the non-DH group. A significant trend was observed among higher creatinine, decreased eGFR as obtained by the MDRD and CG formulas, and the prevalence of DH (P for trend ≤0.003, logistic regression analysis). A multiple logistic regression model adjusted for age, sex, hypertension, diabetes, and hyperlipidemia showed that the lowest eGFR quartiles estimated by MDRD and CG were significantly associated with DH compared with the highest eGFR quartile (adjusted odds ratio, 1.96; 95% confidence interval, 1.22-3.14 by CG, 1.86; 95% confidence interval, 1.17-2.96 by MDRD).

CONCLUSION

Renal function impairment was independently associated with a higher prevalence of DH in a South Korean population.

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

PURPOSE

The relationship between hypothyroidism and primary open angle glaucoma (POAG) has attracted intense interest recently, but the reported results have been controversial. This meta-analysis was carried out to determine the association between hypothyroidism and POAG.

METHODS

The literature was identified from three databases (Web of Science, Embase, and PubMed). The meta-analyses were performed using random-effects models, with results reported as adjusted odds ratios (ORs) with 95% confidence intervals (CI 95%).

RESULTS

A total of 11 studies meeting the inclusion criteria were included in the final meta-analysis. The pooled OR based on 11 risk estimates showed a statistically significant increased risk of POAG prevalence among individuals with hypothyroidism (OR = 1.64, 95% CI = 1.27-2.13). Substantial heterogeneity among these studies was detected (P < 0.001; I2 = 83.2%). Sub-group analysis revealed that the cohort studies and case-control studies showed a significant association between hypothyroidism and POAG, which was not observed in cross-sectional studies. There was no significant publication bias in this study.

CONCLUSIONS

The findings of this meta-analysis indicate that individuals with hypothyroidism have an increased risk of developing POAG.

Comparison of Glaucoma Progression Between Unilateral and Bilateral Disc Hemorrhage Eyes and Associated Risk Factors for Progression

PURPOSE

To compare glaucoma progression between unilateral and bilateral disc hemorrhage (DH) eyes and to determine the associated risk factors.

METHODS

A total of 78 bilateral primary open-angle glaucoma (POAG) patients who had shown one or more occurrences of DH (48 eyes of 38 unilateral DH patients and 30 eyes of 30 bilateral DH patients) were included. Glaucoma progression was defined by visual field (VF) deterioration. The mean VF global indices progression rates in the pre-DH, post-DH and total follow-up periods were compared between the unilateral and bilateral DH groups. The cumulative probability of glaucoma progression between the 2 groups was compared by the Kaplan-Meier survival analysis. Univariate and multivariate Cox proportional hazard models were used to identify the risk factors for glaucoma progression.

RESULTS

Among the mean VF global indices progression rates, only the mean pattern standard deviation progression rate showed a statistically significant difference between the groups (unilateral DH group: 0.30±0.38 dB/y; bilateral DH group: 0.13±0.27 dB/y) (P=0.042). The Kaplan-Meier analysis revealed a greater cumulative probability of progression in the unilateral than in the bilateral DH group (P=0.008). The multivariate Cox's proportional hazard model indicated unilaterality of DH to be a factor associated with glaucoma progression (hazard ratio, 2.587; P=0.030).

CONCLUSIONS

In bilateral POAG patients with DH, unilaterality of DH is associated with glaucoma progression. Therefore, clinicians need to perform careful and frequent follow-up on bilateral POAG patients showing DH in only 1 eye during the follow-up period.

Anti-platelet effects of anti-glaucomatous eye drops: an in vitro study on human platelets

PURPOSE

Altered platelet aggregability has been implicated in the pathogenesis of glaucoma. This study aims to investigate the anti-platelet potential of intraocular pressure lowering drops, with the possibility of establishing it as an additional mechanism of anti-glaucomatous action.

MATERIALS AND METHODS

The anti-aggregating effects of a series of anti-glaucomatous eye drops were determined on human platelets in the platelet aggregation model, using four known aggregating factors (platelet activating factor [PAF], adenosine diphosphate [ADP], thrombin receptor-activating peptide [TRAP], and arachidonic acid [AA]).

RESULTS

Almost all of the tested samples inhibited platelet aggregation induced by PAF, ADP, TRAP, and AA, except for Alphagan, which did not demonstrate inhibition of ADP- and TRAP-induced aggregation at a wide range of concentrations. Trusopt, Betoptic, and Azarga eye drops were the most potent inhibitors of all four aggregating factors, while Alphagan was the least potent (P<0.05).

CONCLUSION

This study shows that anti-glaucomatous eye drops possess anti-platelet effects, and this was shown for the first time by experimenting on human platelets.

Predictive role of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in normal-tension glaucoma

As a type of primary open-angle glaucoma, normal-tension glaucoma (NTG) is a health problem that manifests itself with low intraocular pressure (IOP) levels and preserves its importance for public health care. In population-based screenings, which take the IOP levels of 21mmHg as a cut-off for the diagnosis of glaucoma, the diagnosis is usually delayed, and the treatment is started in an advanced stage by the referred ophthalmologists. NTG is associated with some autoimmune conditions and systemic diseases, such as paraproteinemia, nocturnal hypotension, and migraine. Recently, a simple and cheap test (namely the hemogram) was defined as measure of systemic inflammation, measuring the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). A recent study displayed an altered platelet function in NTG patients. We hypothesize that an automated hemogram analysis for NLR together with IOP measurements may be used to screen NTG patients who are admitted to primary care clinics if any relationship between NTG and NLR could be demonstrated in future researches.

Association Between Nocturnal Blood Pressure Dips and Optic Disc Hemorrhage in Patients With Normal-Tension Glaucoma

PURPOSE

To investigate the effect of nocturnal blood pressure (BP) dips on the occurrence of optic disc hemorrhage (ODH) in normal-tension glaucoma (NTG) patients and determine whether ODH is associated with greater likelihood of visual field progression (VFP).

DESIGN

Prospective case-control study.

METHODS

This study enrolled 698 eyes of 349 consecutive NTG patients who were ≥40 years old, underwent 24-hour intraocular pressure and ambulatory BP monitoring in the habitual position, were examined for ODH every 4-6 months with optic disc photography, and had ≥5 reliable visual field tests with minimum follow-up of 3 years. NTG patients were classified into 2 groups: "nonphysiologic" dippers, including nondippers and overdippers, and "physiologic" dippers. Odds ratios for the association between the "nonphysiologic" group and ODH were calculated using logistic regression models. Kaplan-Meier analyses were performed to compare outcomes with reference to the presence of ODH for VFP.

RESULTS

Overall, ODH and VFP were detected in 107 (15.3%) eyes and 60 (8.6%) eyes among total 698 eyes, respectively. Overdippers showed a significantly greater frequency of ODH than nondippers or dippers. Being an overdipper was a significant and an independent risk factor for ODH occurrence during follow-up. The rates of VFP were 6%, 7%, and 24% for dippers, nondippers, and overdippers, respectively. Eyes with ODH were associated with greater likelihoods of subsequent VFP than those without. VFP occurred only in eyes with ODH.

CONCLUSIONS

Being an overdipper is a significant risk factor for ODH in NTG eyes. The detection of ODH during follow-up is a potent predictor of future VFP.

Optic disc hemorrhage in glaucoma: pathophysiology and prognostic significance

PURPOSE OF REVIEW

This article reviews the recent findings with regard to the pathophysiology and clinical significance of optic disc hemorrhage in glaucoma.

RECENT FINDINGS

Even though the pathophysiology of disc hemorrhage has been investigated in depth, its underlying mechanism remains unclear. The key disc hemorrhage mechanisms currently under discussion are mechanical vascular disruption and associated vascular susceptibilities. Recent technical advances in spectral-domain optical coherence tomography have yielded more compelling evidence of mechanical vascular disruption behind the pathogenesis of disc hemorrhage in glaucoma. Studies show that disc hemorrhage is associated with structural and functional glaucoma progression. Furthermore, recent findings suggest that disc hemorrhage can have different significances according to its location, recurrence, and associated underlying mechanism.

SUMMARY

The underlying mechanism of disc hemorrhage is complex like that of glaucoma. The ongoing controversy respecting the role of disc hemorrhage as a risk factor for glaucoma progression notwithstanding, special attention entailing closer follow-up and/or treatment escalation is recommended for patients with disc hemorrhage. Further studies investigating the unrevealed pathogenesis of disc hemorrhage and its prognostic value in glaucoma are warranted.

Ocular Blood Flow and Influencing Factors for Glaucoma

Open-angle glaucoma (OAG) is characterized by optic nerve fiber atrophy and deterioration of the visual field, corresponding to damage to the optic nerve head. Intraocular pressure (IOP) is currently the only evidence-based, treatable risk factor for OAG. However, normal-tension glaucoma, the most common type of OAG in Asia, is a type of glaucoma with an unclear pathogenesis. Glaucoma is suspected to be a multifactorial disease with IOP-dependent and IOP-independent risk factors, including decreased ocular blood flow (OBF), oxidative stress, decreased axoplasmic flow, and genetic background. A number of epidemiological studies have generated strong evidence that OBF may be an especially important risk factor for the progression of glaucoma. Recent innovations in laser speckle flowgraphy and optical coherence tomography-based angiography have allowed us to noninvasively monitor changes in the microcirculation of the optic nerve head with high reproducibility. Laser speckle flowgraphy-derived measurement parameters include mean blur rate and pulse wave form parameters, whereas the main optical coherence tomography angiography-derived parameter is the vessel index. Decreases in these parameters are associated with the severity of glaucomatous damage, and changes are detectible even in the earliest, preperimetric stage of glaucoma. In the future, OBF analysis may improve significantly because of continuing progress in the development of the relevant instruments. This review will summarize possible connections between systemic and OBF abnormalities and OAG, describe the scientific rationale for these connections, and discuss their potential implications. Thus, this review will summarize the role of OBF in glaucoma pathogenesis and discuss the wide range of IOP-independent risk factors.