A novel hypothesis for the pathogenesis of glaucomatous disc hemorrhage

Characteristics of optic disc hemorrhage and optic nerve changes following acute primary angle closure

Introduction

Acute primary angle closure (APAC) is an emergency ophthalmic presentation and a major cause of irreversible blindness in China. However, only a few studies have focused on the characteristics of optic disc hemorrhage (ODH) during an APAC attack, including its shape, depth, location, scope, and duration after intraocular pressure (IOP) control, along with changes in the optic nerve. This study aimed to analyze the characteristics of ODH and optic nerve changes in patients during their first APAC episode.

Methods

This retrospective study involved 32 eyes from 32 patients with APAC who received sequential treatment and analyzed the following parameters: the highest IOP and its duration, ODH, retinal nerve fiber layer thickness (RNFLT), and mean deviation (MD). We compared parameters obtained from the affected eye (ODH group) and contralateral unaffected eye (control group), as well as intragroup comparisons.

Results

The mean IOP in the ODH group was 64.28 ± 10.36 mmHg, with a duration of 4.44 ± 2.35 days. Flame and splinter shapes accounted for 84.38% of the ODH. The mean ODH duration was 4.81 ± 3.25 weeks. ODH during APAC was isolated to one sector in 59.38% of cases, mostly occurring in the temporal superior and temporal inferior (each accounting for 21.88% of the cases). There was a positive correlation between the extent of hemorrhage and the highest IOP duration (p < 0.001). RNFLT was significantly thickened within 72 h post-IOP control but was thinned by 2 weeks. By 6 months, the thinning stabilized, and there was no difference noted between the ODH and control groups at 12 months. MD partly improved at 6 months post-IOP control, and ODH scope significantly affected the MD (p < 0.001). The duration of high IOP was positively correlated to the ODH scope and MD damage.

Discussion

Timely and effective IOP management is essential for recovering visual function following an APAC attack.

Ancillary PanoMap OCT shows the progression of glaucomatous papillomacular bundle defect with disc haemorrhage on the fovea-disc axis

BACKGROUND/AIMS

To identify the spatial relationship between disc haemorrhage (DH) on the fovea-disc axis and retinal nerve fibre layer (RNFL) defect in the papillomacular bundle (PMB) using ancillary PanoMap optical coherence tomography (OCT).

METHODS

We investigated the presence and progression of spatially corresponding PMB defects in glaucomatous eyes with temporally located DH on the fovea-disc axis (FoDi-DH). We identified PMB defects using ancillary PanoMap OCT with guided progression analysis, in addition to red-free photographs.

RESULTS

We studied 36 eyes of 35 glaucoma patients with FoDi-DH, pre-existing PMB defects were observed in 18 eyes (50.0%) at the time and location of the initial FoDi-DH occurrence, 14 (38.9%) of which progressed during the follow-up period. New development of PMB defects occurred in 15 (41.7%) of 18 eyes without pre-existing PMB defects. Overall, FoDi-DH was associated with PMB defects in 33 (91.7%) eyes at locations spatially overlapping the PMB defect. Red-free photography and OCT were complementary in detecting PMB defects and progression. Among 47 cases, 20 were concordant, while 10 and 17 were detected only in photography and OCT, respectively. The central visual field defect increased significantly throughout the follow-up period (p=0.006).

CONCLUSION

Most FoDi-DH cases were related to the presence and progression of glaucomatous PMB defects at locations spatially overlapping the defect. OCT helped clarify changes in PMB defects detected by red-free photograph and the detection of photo-negative PMB defects as well. Similar to inferotemporal and superotemporal-direction DH, temporal DH on the PMB may be an indicator of ongoing RNFL damage that deserves close attention.

Neurovascular dysfunction in glaucoma

Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.

Cerebrospinal Fluid Pressure Reduction Induces Glia-Mediated Retinal Inflammation and Leads to Retinal Ganglion Cell Injury in Rats

Low intracranial pressure (LICP)-induced translaminar cribrosa pressure difference (TLCPD) elevation has been proven as a risk factor in glaucomatous neurodegeneration, whereas the underlying retinal immune features of LICP-induced retinal ganglion cells (RGC) injury remain elusive. Here, we identified the retinal immune characteristics of LICP rats, and minocycline (Mino) treatment was utilized to analyze its inhibitory role in glia-mediated retinal inflammation of LICP rats. The results showed that retrograde axonal transport was decreased in LICP rats without significant RGC loss, indicating the RGC injury was at an early stage before the morphological loss. The activation of retinal microglia and astrocytes with morphologic and M1 or A1-marker alternations was detected in TLCPD elevation rats, the activation level is more dramatic in HIOP rats than in the LICP rats (P<0.05). Besides, we detected reduced retinal tight junction protein expressions, accompanied by specific imbalance patterns of T lymphocytes in the retina of both LICP and HIOP rats (P<0.05). Further Mino treatment showed an effective inhibitory role in glia-driven inflammatory responses in LICP rats, including improving retrograde axonal transport, inhibiting retinal glial activation and proinflammatory subtype polarization, and alleviating the blood-retina barrier compromise. This study identified the glia-mediated retinal inflammation features triggered by LICP stimulus, and Mino application exhibited an effective role in the inhibition of retinal glia-mediated inflammation in LICP-induced TLCPD elevation rats.

Fluctuation of Intraocular Pressure and Vascular Factors Are Associated With the Development of Epiretinal Membrane in Glaucoma

PURPOSE

To identify factors associated with the development of epiretinal membranes (ERM) in glaucoma patients.

DESIGN

Multicenter, propensity-score matched, case-control study.

METHODS

One hundred ninety-two eyes of 192 patients with glaucoma from the Catholic Medical Center Glaucoma Suspect Cohort Study were analyzed. We identified 64 eyes who developed ERM from the cohort, and 128 eyes without ERM were selected by propensity score matching (1:2) according to baseline age and mean deviation (MD) of the visual field (VF). Demographic, systemic, and ocular characteristics were determined at baseline. Intraocular pressure (IOP) was measured, including baseline, mean IOP, and IOP fluctuation. Early-stage ERM, defined as translucent membrane with no underlying retinal distortion, was detected by fundus photography and optical coherence tomography. Central VF progression was considered when new VF defets developed in one either or both hemifields or when there was an increase of 3 or more abnormal points within 12 points of central 10° fixation. Autonomic nervous system status was evaluated by heart rate variability.

RESULTS

Patients who developed ERM were more frequently receiving medication for systemic hypertension and had higher systolic blood pressure, greater IOP fluctuation, more frequent disc hemorrhage (DH), worse VF MD, and a higher rate of central VF progression than patients without ERM. Additionally, patients with early glaucoma who developed ERM had higher rate of autonomic imbalance while patients with moderate-to-advanced glaucoma who developed ERM had greater baseline and peak IOP and worse MD of the last follow-up VF (MD < 6.0 dB). Older age (P = .048), medication for systemic hypertension (P < .001), IOP fluctuation (P < .001), presence of DH (P < .001), and worse last MD of VF (P = .033) were significantly associated with ERM in Cox proportional hazard analysis.

CONCLUSIONS

Early stage of ERMs in glaucomatous eyes are significantly associated with glaucoma progression, medication of systemic hypertension, presence of DH, and IOP fluctuation. These suggest that glaucoma patients who develop early stage of ERMs should be carefully monitored in terms of IOP fluctuation, vascular factors, and glaucoma progression.

Wedge Defects on Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma: Prevalence and Associated Clinical Factors

PRCIS

Among subjects with glaucoma, wedge-shaped defects on optical coherence tomography angiography (OCTA) were associated with disc hemorrhages (DH), paracentral visual field (VF) defects, increased cup-to-disc ratio (CDR), and thinner retinal nerve fiber layer (RNFL).

PURPOSE

To examine determinants of wedge defects on peripapillary OCTA in glaucoma.

MATERIALS AND METHODS

A total of 278 eyes of 186 subjects with mild to severe primary open-angle glaucoma underwent 6×6 spectral-domain OCTA imaging of the superficial peripapillary retina from 2016 to 2020 at an academic practice. Wedge defects were defined as focal microvasculature loss that extends outward from the optic nerve in an arcuate, wedge shape. Logistic regression models controlling for intereye correlation identified variables significantly associated with wedge defects. Eyes with profound microvasculature loss in both hemispheres were excluded. Candidate variables included: age, sex, race or ethnicity, diabetes, hypertension, follow-up duration, baseline untreated intraocular pressure, intraocular pressure at time of imaging, DH history, paracentral VF defects, CDR, central corneal thickness, spherical equivalent, VF mean deviation, RNFL thickness, and glaucoma stage.

RESULTS

Of 278 eyes, 126 (45.3%) had wedge defects in at least 1 hemisphere. In our multivariable logistic regression model, wedge defects were associated with DH history [odds ratio (OR): 3.19, 95% confidence interval (CI): 1.05-9.69, P=0.041], paracentral VF defects [OR: 4.38 (95% CI: 2.11-9.11), P<0.0001], larger CDR [OR: 1.27 (95% CI: 1.03-1.56), P=0.024, per 0.1 increase], and thinner RNFL [OR: 1.71 (95% CI: 1.25-2.34), P=0.0009, per 10 μm decrease].

CONCLUSION

DH history and paracentral VF defects were independently associated with wedge defects on OCTA, which was present in 45.3% of primary open-angle glaucoma patients. These findings may provide insight into glaucoma pathogenesis.

Postradiation Optic Atrophy Is Associated With Intraocular Pressure and May Manifest With Neuroretinal Rim Thinning

BACKGROUND

To determine risk factors for postradiation optic atrophy (PROA) after plaque radiotherapy for uveal melanoma.

METHODS

A single center, retrospective cohort study of patients diagnosed with uveal melanoma involving choroid and/or ciliary body treated with plaque between January 1, 2008, and December 31, 2016. Outcomes included development of PROA with pallor alone or with concomitant neuroretinal rim thinning (NRT). Cox regression analysis was performed to identify risk factors for PROA.

RESULTS

Of 78 plaque-irradiated patients, PROA developed in 41 (53%), with concomitant NRT in 15 (19%). Risk factors for PROA of any type included presentation with worse visual acuity (odds ratio [95% confidence interval] 5.6 [2.3-14.1], P < 0.001), higher baseline intraocular pressure (IOP; 14 vs 16 mm Hg) (1.1 [1.0-1.2], P = 0.03), shorter tumor distance to optic disc (1.3 [1.2-1.5], P < 0.001) and foveola (1.2 [1.1-1.3], P < 0.001), subfoveal subretinal fluid (3.8 [2.0-7.1], P < 0.001), greater radiation prescription depth (1.3 [1.1-1.6], P = 0.002), dose to fovea (point dose) (1.01 [1.01-1.02], P < 0.001), and mean (1.02 [1.02-1.03], P < 0.001) and maximum dose to optic disc per 1 Gy increase (1.02 [1.01-1.03], P < 0.001). On multivariate modeling, dose to disc, baseline IOP, and subfoveal fluid remained significant. Subanalysis revealed risk factors for pallor with NRT of greater mean radiation dose to disc (1.03 [1.01-1.05], P = 0.003), higher maximum IOP (17 vs 20 mm Hg) (1.4 [1.2-1.7], P < 0.001), and subfoveal fluid (12 [2-63], P = 0.004).

CONCLUSION

PROA may result in NRT in addition to optic disc pallor. Risk factors for PROA included higher radiation dose to optic disc, higher baseline IOP, and subfoveal fluid. Higher maximum IOP contributed to concomitant NRT.

Rates of Circumpapillary Retinal Nerve Fiber Layer Thinning and Capillary Density Loss in Glaucomatous Eyes with Disc Hemorrhage

PURPOSE

To investigate longitudinal changes in rates of optic nerve head circumpapillary retinal nerve fiber layer (cpRNFL) thinning and vessel density loss in patients with primary open-angle glaucoma with or without a history of disc hemorrhage (DH).

DESIGN

Observational cohort.

METHODS

In this longitudinal study, 34 eyes with DH and 134 eyes without DH that had ≥1.5 years of follow-up and 3 optical coherence tomography and optical coherence tomography angiography follow-up scans were enrolled. A linear mixed-effects model was used to compare the rates of cpRNFL thinning and vessel density loss between DH and non-DH eyes.

RESULTS

Rates of whole image capillary density loss were faster in the DH group compared with the non-DH group (mean difference [95% confidence interval] -0.32% [-0.59% to -0.04%] per year; P = .027). Faster mean rates of vessel density loss were found in the inferotemporal, inferonasal, and nasal sectors in eyes with DH than without DH (P < .05). There was no statistically significant difference in the global rate of cpRNFL thinning between the 2 groups (P = .679). The mean rate of cpRNFL thinning was faster in the DH group compared with the non-DH group only in the inferotemporal sector (mean difference [95% confidence interval] -1.01 μm (-1.62 μm to -0.40 μm) per year; P = .001).

CONCLUSIONS

Mean rates of vessel density loss between DH and non-DH eyes were different not only in the affected area but also in the other regions. In contrast, a significant difference in cpRNFL thinning between the 2 groups was detected only in the inferotemporal sector. Disc hemorrhage is an independent predictor of faster vessel density loss in glaucoma suspects and patients with primary open-angle glaucoma.

Optic Disc Hemorrhage Is Not Associated with Global Choroidal Vessel Loss, but Is Associated with Localized Choroidal Vessel Loss in Glaucoma

Purpose: To investigate the relationship between optic disc hemorrhage (ODH) and the geographic pattern (regional vs. global) of parapapillary choroidal vessel density (pCVD) loss within the β-parapapillary atrophy (β-PPA) in open-angle glaucoma (OAG) Methods: This retrospective cross-sectional study included 100 OAG eyes with visual field (VF) defects confined to a single hemifield (50 with and 50 without ODH, matched for age (≤10 years) and VF severity (≤1 decibel) at the same hemifield), as well as 50 healthy eyes. The pCVD was measured using optical coherence tomography angiography (OCTA). The relationships between pCVD and clinical factors were assessed globally and regionally. Logistic regression analyses were performed to determine the clinical factors associated with the presence of ODH. Results: The pCVD values within ODH-affected hemiretinae of ODH+ eyes were significantly lower than those in the matched hemiretinae of ODH− eyes (p = 0.001). The presence of ODH was significantly correlated with a lower pCVD within ODH-dominant inferior hemiretinae (p < 0.05). Lower pCVD values at ODH-affected hemiretinae was significantly associated with the presence of ODH (p < 0.05). Conclusions: OAG eyes with ODH demonstrate a greater severity of regional pCVD loss at the hemiretinae spatially corresponding to the ODH location compared to OAG eyes without ODH.

Disc Hemorrhages Are Associated With Localized Three-Dimensional Neuroretinal Rim Thickness Progression in Open-Angle Glaucoma

PURPOSE

To evaluate the relationship between the occurrence of optic disc hemorrhages (DH) and glaucoma progression as determined by multiple glaucoma testing modalities.

DESIGN

Prospective cohort study.

METHODS

A longitudinal study was undertaken of 124 open-angle glaucoma patients who had yearly disc photography, visual fields (VFs), spectral-domain optical coherence tomography (SD-OCT), retinal nerve fiber layer (RNFL) thickness scans, and optic nerve volume scans (Spectralis), all performed on the same day over a 5-year period. The minimum distance band (MDB) thickness, a 3-dimensional (3D) neuroretinal rim parameter, was calculated from optic nerve volume scans. Patients were classified as glaucoma progressors or glaucoma nonprogressors using event-based analysis.

RESULTS

Of 124 open-angle glaucoma patients, 19 (15.3%) had 1 or more DHs on yearly disc photographs. Presence of a DH was associated with localized 3D neuroretinal rim thickness progression (superior MDB progression; odds ratio: 3.96; P = .04) but not with global or inferior MDB progression (P = .14 and .81, respectively), DP progression (P = .08), VF progression (P = .45), or RNFL global, inferior, or superior progression (P = .17, .26, and .76, respectively). In the majority of patients with MDB progression (14/17 or 82%), the progression was noted before or concurrently with the first instance of DH.

CONCLUSIONS

Glaucoma progression detected by high-density 3D SD-OCT neuroretinal rim measurements preceded DH occurrence in the majority of patients. These findings support the hypothesis that DHs are indicators of ongoing glaucoma progression rather than discrete events that cause subsequent progression.

A Review of Potential Novel Glaucoma Therapeutic Options Independent of Intraocular Pressure

Glaucoma, a progressive optic neuropathy characterized by retinal ganglion cell degeneration and visual field loss, is the leading cause of irreversible blindness worldwide. Intraocular pressure (IOP) is presently the only modifiable risk factor demonstrated to slow or halt disease progression; however, glaucomatous damage persists in almost 50% of patients despite significant IOP reduction. Many studies have investigated the non-IOP-related risk factors that contribute to glaucoma progression as well as interventions that can prevent or delay glaucomatous neurodegeneration and preserve vision throughout life, independently of IOP. A vast number of experimental studies have reported effective neuroprotection in glaucoma, and clinical studies are ongoing attempting to provide strong evidence of effectiveness of these interventions. In this review, we look into the current understanding of the pathophysiology of glaucoma and explore the recent advances in non-IOP related strategies for neuroprotection and neuroregeneration in glaucoma.

Characteristics of Central Visual Field Progression in Eyes with Optic Disc Hemorrhage

PURPOSE

To investigate the characteristics and rate of central visual field loss after optic disc hemorrhage (DH).

DESIGN

Prospective cohort study.

METHODS

Three hundred forty-three eyes of 220 subjects who had ≥3 years of follow-up with a minimum of 5 visits with 10-2 and 24-2 visual field (VF) were recruited. Rates of 10-2 mean deviation (MD) loss in each hemifield and predefined zones were compared using linear mixed-effects models in DH and non-DH eyes. Clustered pointwise regression analysis was also used to define central VF progressors and compared with 24-2 VF loss using guided progression analysis.

RESULTS

Thirty-nine eyes with DH and 304 eyes without DH had a mean follow-up of 5.2 years. Eyes with DH had rates of 10-2 MD loss that were 3 times faster than non-DH eyes (mean difference -0.36 dB/year [95% confidence interval 0.54-0.18]; P < .001) and were 3.7 times more likely to progress (P = .002). A larger proportion of glaucomatous eyes showed central VF progression rather than peripheral VF progression in the DH group (30.8% vs. 20.5%) compared with the non-DH group (10.9% vs. 9.2%). In early glaucoma, the rate of 10-2 MD loss was 5.5 times faster in DH eyes than in non-DH eyes (P < .001). Superonasal and superotemporal central VF regions progressed more rapidly than other regions, especially in DH eyes.

CONCLUSION

Central VF loss is accelerated in glaucoma eyes with DH and it corresponds topographically to the DH location. In patients with glaucoma with DH, one should consider supplementing 10-2 VFs with 24-2 VFS to monitor the disease.

Progression of Parapapillary Choroidal Microvascular Dropout After Disc Hemorrhage in Glaucoma Patients: 2 Case Reports

PURPOSE

Microvasculature dropout (MvD) is a novel finding seen in optical coherence tomography angiography (OCTA), which is characterized by a localized dehiscence of the choriocapillaris in the parapapillary atrophy area. Disc hemorrhage (DH) is an important factor often associated with the development and especially progression of glaucoma. Here, we present 2 cases of MvD progression with DH.

METHODS AND RESULTS

Case 1: A 62-year-old female patient with normal tension glaucoma in both her eyes had recurrent DH at the inferior area of her right eye. A new DH was observed in the inferotemporal area of the right eye with MvD progression on OCTA in the same direction three months from the baseline.Case 2: A 57-year-old female patient with bilateral steroid-induced secondary glaucoma also had recurrent DH in her right eye. Four months from the baseline, DH occurred in the superotemporal and inferotemporal area of the right eye, and MvD was detected on OCTA in the superotemporal corresponding direction. After 19 months from the baseline, OCTA was repeated. The DH had resolved, but the superotemporal MvD persisted.

CONCLUSIONS

The 2 cases presented here are the first to report on the relationship between MvD progression and DH. MvD as visualized in OCTA imaging looks to be of clinical importance, and hopefully future studies will reveal the actual connection between MvD, DH, and glaucoma progression.

Disc hemorrhage following peripapillary retinoschisis in glaucoma: a case report

BACKGROUND

Disc hemorrhage (DH) is an important factor often associated with the development and especially progression of glaucoma. In contrast, some studies have reported peripapillary retinoschisis in glaucoma, but it is not recognized as a pathognomonic finding, and opinions on the clinical significance of retinoschisis are not consistent. Here,we present the case of DH following peripapillary retinoschisis in the same area within the same glaucomatous eye.

CASE PRESENTATION

A 70-year-old man with high intraocular pressure (IOP) was referred to the glaucoma clinic. At the time of the baseline study, the IOP was 30mmHg, and peripapillary retinoschisis was discovered at 7 o'clock on the periphery of the optic nerve with swept-source optical coherence tomography. Accompanying retinal nerve fiber layer defect were manifest in the inferotemporal part with red-free fundus photography. Under the impression of open-angle glaucoma, we prescribe latanoprost ophthalmic solution. Eight months later, the IOP was 17mmHg, and the peripapillary retinoschisis had disappeared. DH was observed in the inferotemporal area in the same direction as that of the previous peripapillary retinoschisis.

CONCLUSIONS

The case presented here are the first to report on the relationship between peripapillary retinoschisis and DH. Hopefully future studies will reveal the actual connection between peripapillary retinoschisis and DH.

So-Called Lamina Cribrosa Defects May Mitigate IOP-Induced Neural Tissue Insult

Purpose

The prevailing theory about the function of lamina cribrosa (LC) connective tissues is that they provide structural support to adjacent neural tissues. Missing connective tissues would compromise this support and therefore are regarded as “LC defects”, despite scarce actual evidence of their role. We examined how so-called LC defects alter IOP-related mechanical insult to the LC neural tissues.

Methods

We built numerical models incorporating LC microstructure from polarized light microscopy images. To simulate LC defects of varying sizes, individual beams were progressively removed. We then compared intraocular pressure (IOP)-induced neural tissue deformations between models with and without defects. To better understand the consequences of defect development, we also compared neural tissue deformations between models with partial and complete loss of a beam.

Results

The maximum stretch of neural tissues decreased non-monotonically with defect size. Maximum stretch in the model with the largest defect decreased by 40% in comparison to the model with no defects. Partial loss of a beam increased the maximum stretch of neural tissues in its adjacent pores by 162%, compared with 63% in the model with complete loss of a beam.

Conclusions

Missing LC connective tissues can mitigate IOP-induced neural tissue insult, suggesting that the role of the LC connective tissues is more complex than simply fortifying against IOP. The numerical models further predict that partial loss of a beam is biomechanically considerably worse than complete loss of a beam, perhaps explaining why defects have been reported clinically but partial beams have not.

Acute Onset Optic Disc Hemorrhage Following Pharmacologic Mydriasis

PURPOSE

To report two unusual cases of optic disc hemorrhage occurring following pharmacologic mydriasis.

OBSERVATION

A 78-year old woman and 60-year old man with primary open angle glaucoma developed optic disc hemorrhages shortly after pupillary dilation.

CONCLUSION AND IMPORTANCE

Cycloplegia may cause subtle shifts in vitreous and lamina cribrosa position that may result in the formation of optic disc hemorrhages in susceptible glaucomatous eyes.

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

Purpose

To investigate the association between peripheral vasospasm and the visual field (VF) progression rate in patients with normal-tension glaucoma (NTG) with low-teen intraocular pressure (IOP).

Methods

The finger temperature of 113 NTG patients was measured before and after exposure to ice water using a Temperature gun (cold pressor test). These patients had confirmed VF progression, despite a low-teen IOP during a follow-up period of >5 years. VF progression rates were calculated as the slope of the visual field index (VFI) and mean deviation (MD) over time. Demographic, systemic, and ocular factors and VF progression rates were compared, based on the cold pressor test results. A regression analysis was used to investigate the factors affecting VF progression rates.

Results

Mean age, initial IOP, mean IOP during the follow-up period, and initial VF MD were 57.1 years, 15.8 mmHg, 12.0 mmHg, and -5.2 dB, respectively. When patients were divided into two groups (less vasospasm and more vasospasm) according to changes in temperature after exposure to ice water, the VF progression rate was significantly faster in the group with more vasospasm. In a multiple regression analysis, older age, worse initial VF MD, and greater decrease in finger temperature after ice water exposure were significantly associated with faster VF progression rates.

Conclusion

An excessive drop in finger temperature after exposure to ice water was significantly associated with faster VF progression in patients with low-teen NTG. This suggests that the blood flow in the optic nerve head may also be disturbed by peripheral vasospasm, accelerating glaucomatous damage regardless of IOP.

Identification of risk factors for retinal vascular events in a population-based cross-sectional study in Rumoi, Japan

We conducted a population-based, cross-sectional study in Japan to identify risk factors for retinal vascular events separately by gender. Forty years or older participants were recruited. Fundus photographs were taken, and lifestyle and health characteristics were determined through a questionnaire and physical examinations. We compared the group of those who had retinal vascular events and those who did not. A total of 1689 participants (964 men) were deemed eligible for the study and retinal vascular events were seen in 59 subjects (3.7% of the men, 3.2% of the women). Self-reported diabetes mellitus was significantly associated with the vascular events in each gender [odds ratio (OR) = 6.97, 6.19 (men, women); 95% confidence interval (CI) 3.02–15.9, 2.25–17.0; p < 0.001]. Higher systolic blood pressure (OR = 1.03; 95% CI 1.01–1.04; p = 0.006) and lower frequency of meat consumption (OR = 0.73; 95% CI 0.54–0.99; p = 0.04) were independently associated with the vascular events in men. In women, while vascular events were associated with self-reported hypertension (OR = 2.64; 95% CI 1.03–6.74; p = 0.04), no association was seen with systolic blood pressure. Women with hypertension may need extra care, not only for blood pressure.

The occurrence of optic disc haemorrhage in primary open-angle glaucoma eyes with lower normal pressure and its relating factors

PURPOSE

To report the occurrence probability of disc haemorrhage (DH) and risk factors for it in otherwise healthy Japanese normal-tension glaucoma (NTG) patients who had lower normal intraocular pressure (IOP) and were followed without treatment for 5 years.

METHODS

A prospective observational study. Normal-tension glaucoma (NTG) patients with IOP consistently ≤15 mmHg without treatment were enrolled. The presence or absence of DH was checked semi-annually on the fundus photographs by three independent observers, while patients were followed without treatment. Cox proportional hazards model taking inter-eye correlation into consideration was adopted to identify risk factors for DH occurrence. The main outcomes were DH occurrence probability during 5-year period and its risk factors.

RESULTS

One hundred seventeen eyes of 90 patients with mean age of 54.1 years, mean deviation value of -3.6 decibels and mean IOP during follow-up of 12.4 mmHg were included. Disc haemorrhage (DH) was observed at least once in 34 eyes and more than twice in 15 eyes during the follow-up. The DH occurrence probability at 5 years was 31% (95% confidence interval: 21-40%), and lower myopic refraction (HR = 1.18; p = 0.018), higher IOP during follow-up (HR = 1.35; p = 0.047) and presence of DH at baseline (HR = 4.19; p = 0.002) were its risk factors.

CONCLUSION

Disc haemorrhage (DH) occurrence probability of Japanese healthy NTG patients with mean IOP of 12.4 mmHg and no systemic and/or topical treatment was 31% at 5 years. Lower myopic refraction, higher IOP and its existence at baseline were its risk factors.

Optic nerve head anatomy in myopia and glaucoma, including parapapillary zones alpha, beta, gamma and delta: Histology and clinical features

The optic nerve head can morphologically be differentiated into the optic disc with the lamina cribrosa as its basis, and the parapapillary region with zones alpha (irregular pigmentation due to irregularities of the retinal pigment epithelium (RPE) and peripheral location), beta zone (complete RPE loss while Bruch's membrane (BM) is present), gamma zone (absence of BM), and delta zone (elongated and thinned peripapillary scleral flange) within gamma zone and located at the peripapillary ring. Alpha zone is present in almost all eyes. Beta zone is associated with glaucoma and may develop due to a IOP rise-dependent parapapillary up-piling of RPE. Gamma zone may develop due to a shift of the non-enlarged BM opening (BMO) in moderate myopia, while in highly myopic eyes, the BMO enlarges and a circular gamma zone and delta zone develop. The ophthalmoscopic shape and size of the optic disc is markedly influenced by a myopic shift of BMO, usually into the temporal direction, leading to a BM overhanging into the intrapapillary compartment at the nasal disc border, a secondary lack of BM in the temporal parapapillary region (leading to gamma zone in non-highly myopic eyes), and an ocular optic nerve canal running obliquely from centrally posteriorly to nasally anteriorly. In highly myopic eyes (cut-off for high myopia at approximately -8 diopters or an axial length of 26.5 mm), the optic disc area enlarges, the lamina cribrosa thus enlarges in area and decreases in thickness, and the BMO increases, leading to a circular gamma zone and delta zone in highly myopic eyes.

Disc Hemorrhages Are Associated With the Presence and Progression of Glaucomatous Central Visual Field Defects

PRECIS

In this prospective cohort study, disc hemorrhages were associated with more severe central damage on 24-2 and 10-2 visual fields (VFs), and faster progression globally on 24-2 VFs and centrally on 10-2 VFs.

PURPOSE

To study the relationship between disc hemorrhage (DH) and the presence and progression of glaucomatous central VF damage.

METHODS

Cross-sectional and longitudinal analyses were performed on data from the African Descent and Glaucoma Evaluation Study (ADAGES) cohort. Two masked investigators reviewed disc photographs for the presence and location of DH. 24-2 central VF damage was based on the number of test locations within the central 10 degrees of the 24-2 field pattern deviation and their mean total deviation (MTD). 10-2 central VF damage was based on pattern deviation and MTD. Main outcome measures were the association between DH and presence of central VF damage and between DH and worsening of VF.

RESULTS

DH was detected in 21 of 335 eyes (6.2%). In the cross-sectional analysis, DH was significantly associated with more severe central damage on 24-2 [incidence rate ratio=1.47; 95% confidence interval (CI)=1.02-2.12; P=0.035] and 10-2 VFs (incidence rate ratio=1.81; 95% CI=1.26-2.60; P=0.001). In the longitudinal analysis, DH eyes progressed faster than non-DH eyes based on 24-2 global MTD rates (difference in slopes, β=-0.06; 95% CI=-0.11 to -0.01; P=0.009) and 10-2 MTD rates (β=-0.10; 95% CI=-0.14 to -0.06; P< 0.001), but not 24-2 central MTD rates (β=-0.02; 95% CI=-0.078 to 0.026; P=0.338).

CONCLUSION

DH was associated with the presence and progression of central VF defects. DH identification should prompt intensive central VF monitoring and surveillance with 10-2 fields to detect progression.

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 Rate of Change between Bruch's Membrane Opening Minimum Rim Width and Retinal Nerve Fiber Layer in Eyes Showing Optic Disc Hemorrhage

PURPOSE

To investigate and compare the longitudinal rate of change of Bruch's membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness in eyes showing optic disc hemorrhage(DH).

DESIGN

Observational case series.

METHODS

A total of 82 subjects(82 eyes) showing DH who had undergone more than five reliable spectral-domain optical coherence tomography (OCT) tests were included. BMO-MRW and RNFL were measured with OCT at 3-month intervals. The rates of change in global and each Garway-Heath sector were calculated with a linear mixed-effects model after adjusting for age, sex, and BMO area.

RESULTS

The mean follow-up period was 21.57 ± 7.88 months with a mean number of 7.88 ± 2.39 OCT tests. Baseline demographics were age (58.37 ± 10.65 y); 46.3% were female; and the mean deviation was -4.41 ± 5.04 dB. The global rate of change in BMO-MRW was -3.507 ± 0.675 μm/y and in -1.404 ± 0.208 μm/y in RNFL. The rate of change was the greatest in the inferotemporal sector, which was -9.141 ± 1.254 μm/y in BMO-MRW and -4.204 ± 0.490 μm/y in the RNFL. The rate of change was significantly greater in BMO-MRW than in the RNFL in all sectors, except for the nasal sector (P < .05). Percentage of reduction was significantly greater in BMO-MRW than in RNFL in the inferotemporal and superotemporal sectors (P < .05).

CONCLUSIONS

BMO-MRW showed a significantly greater rate of change than RNFL in eyes showing DH, especially in the inferotemporal and superotemporal sectors in percentage of reduction. Thus, it may be more advantageous to detect glaucomatous progression earlier in BMO-MRW than in the RNFL in eyes showing DH that are more likely to progress.

Densitometric Profiles of Optic Disc Hemorrhages in the Ocular Hypertension Treatment Study

PURPOSE

The origin of blood in glaucoma-related disc hemorrhages (DH) remains unknown. A prior clinic-based study of primary open-angle glaucoma (POAG)-related DH showed that they had grayscale pixel intensities more similar to blood from retinal macroaneurysms and adjacent retinal arterioles than to blood from retinal vein occlusions or adjacent retinal venules, suggesting an arterial source. Here we assessed the densitometric profile of DH from fundus photographs in the Ocular Hypertension Treatment Study (OHTS).

DESIGN

Retrospective cross-sectional study of prospectively collected images.

METHODS

Stereo disc photographs of 161 DH events from 83 OHTS participants (mean age [standard deviation (SD)]: 65.6 [9.2] years; 46.6% female; 13.0% black race) were imported into ImageJ to measure densitometry differences (adjacent arterioles minus DH [ΔA] or venules minus DH [ΔV]). Their size as percentage of disc area, ratio of length to midpoint width, and location relative to the disc margin were also analyzed. We performed t tests to compare ΔA and ΔV, analysis of variance to compare ΔA and ΔV across DH recurrent events, and multivariable linear regression to identify determinants of ΔA and ΔV.

RESULTS

Mean (SD) ΔA and ΔV were -2.2 (8.7) and -11.4 (9.7) pixel intensity units, respectively (P < .001). ΔA and ΔV each did not differ significantly across recurrence of DH (P ≥ .92) or between DH events with and without POAG (P ≥ .26).

CONCLUSIONS

OHTS DH had densitometric measurements more similar in magnitude to adjacent arterioles than venules, supporting an arterial origin for DH. Vascular dysregulation may contribute to disc hemorrhage formation in ocular hypertension.

Role of radially aligned scleral collagen fibers in optic nerve head biomechanics

Collagen fibers organized circumferentially around the canal in the peripapillary sclera are thought to provide biomechanical support to the sensitive tissues within the optic nerve head (ONH). Recent studies have demonstrated the existence of a family of fibers in the innermost sclera organized radially from the scleral canal. Our goal was to determine the role of these radial fibers in the sensitivity of scleral canal biomechanics to acute increases in intraocular pressure (IOP). Following the same general approach of previous parametric sensitivity studies, we created nonlinear generic finite element models of a posterior pole with various combinations of radial and circumferential fibers at an IOP of 0 mmHg. We then simulated the effects of normal and elevated IOP levels (15 and 30 mmHg). We monitored four IOP-induced geometric changes: peripapillary sclera stretch, scleral canal displacement, lamina cribrosa displacement, and scleral canal expansion. In addition, we examined the radial (maximum tension) and through-thickness (maximum compression) strains within the ONH tissues. Our models predicted that: 1) radial fibers reduced the posterior displacement of the lamina, especially at elevated IOP; 2) radial fibers reduced IOP-induced radial strain within the peripapillary sclera and retinal tissue; and 3) a combination of radial and circumferential fibers maintained strains within the ONH at a level similar to those conferred by circumferential fibers alone. In conclusion, radial fibers provide support for the posterior globe, additional to that provided by circumferential fibers. Most importantly, a combination of both fiber families can better protect ONH tissues from excessive IOP-induced deformation than either alone.

Optic disc hemorrhage in nonglaucomatous eyes: A cross-sectional study with average 8-year follow-up

Purpose

To characterize changes in the retinal nerve fiber layer (RNFL) and peripapillary vessel density (VD) at the site of disc hemorrhage (DH) in nonglaucomatous eyes.

Materials and methods

This retrospective cross-sectional study included nonglaucomatous eyes diagnosed with unilateral DH. The change of DH was recorded using disc photography. Both anatomical data and functional visual field (VF) data were collected using optical coherence tomography angiography and Humphrey VF examination.

Results

Sixteen patients were included with average follow-up duration of 95 months. Almost half of DH episodes was initially presented at the inferotemporal area of the optic disc. Pigment formation at the previous DH site after resolution was noted in 12.5% of eyes. Sectoral radial peripapillary VD at the DH site was significantly lower in DH eyes than in the control group; however, the sectoral RNFL thickness at the DH site was not significantly decreased. Progression of the VF defect corresponding to the DH site was found in 81.3% of eyes despite regular use of antiglaucoma agents. The mean change in the VF mean deviation was –0.64 dB/year in DH eyes.

Conclusion

During long follow-up periods, decreased peripapillary VD at the DH site and progression of the VF defect corresponding to the DH site were detected in nonglaucomatous eyes. Retinal pigmentation with an RNFL defect is a clue for DH, although RNFL showed no significant change. Antiglaucoma treatment may not prevent the deterioration of visual function.

Role of glia in optic nerve

Glial cells are critically important for maintenance of neuronal activity in the central nervous system (CNS), including the optic nerve (ON). However, the ON has several unique characteristics, such as an extremely high myelination level of retinal ganglion cell (RGC) axons throughout the length of the nerve (with virtually all fibers myelinated by 7 months of age in humans), lack of synapses and very narrow geometry. Moreover, the optic nerve head (ONH) - a region where the RGC axons exit the eye - represents an interesting area that is morphologically distinct in different species. In many cases of multiple sclerosis (demyelinating disease of the CNS) vision problems are the first manifestation of the disease, suggesting that RGCs and/or glia in the ON are more sensitive to pathological conditions than cells in other parts of the CNS. Here, we summarize current knowledge on glial organization and function in the ON, focusing on glial support of RGCs. We cover both well-established concepts on the important role of glial cells in ON health and new findings, including novel insights into mechanisms of remyelination, microglia/NG2 cell-cell interaction, astrocyte reactivity and the regulation of reactive astrogliosis by mitochondrial fragmentation in microglia.

Association between Rates of Retinal Nerve Fiber Layer Thinning after Intraocular Pressure-Lowering Procedures and Disc Hemorrhage

Purpose

To compare the rates of retinal nerve fiber layer (RNFL) thinning after intraocular pressure (IOP) lowering procedures in eyes with or without disc hemorrhage (DH) history.

Design

Observational cohort study.

Methods

A total of 166 primary open angle glaucoma (POAG) eyes and glaucoma suspect eyes (37 eyes with DH history (DH group) and 129 eyes without DH (non-DH group)) were included from the African Decent and Glaucoma Evaluation Study (ADAGES) and the Diagnostic Innovations in Glaucoma Study (DIGS). Subjects underwent stereoscopic optic disc photography annually and spectral-domain optical coherence tomography (OCT) RNFL thickness measurements every 6 months. The rates of RNFL thinning were compared in eyes with and without DH using univariate and multivariable linear mixed effects models.

Main Outcome Measures

The rates of RNFL thinning.

Results

The mean follow-up of DH group and non-DH group was 4.6 years and 4.2 years, respectively. DH group had more procedures (2.4 vs. 1.9, P= 0.080) before follow-up, and more medications (1.8 vs. 1.4, P= 0.052) and lower mean IOP (12.69 mmHg vs. 14.41 mmHg, P= 0.012) during follow-up compared to non-DH group. When mean IOP was adjusted as a covariate in the model, the RNFL thinning rate in the DH group was 2-fold faster than in the non-DH group (-0.61 μm /year vs. -0.33 μm /year, P= 0.025). Higher mean IOP during follow-up was associated with a faster rate of RNFL thinning after procedures.

Conclusions

POAG or glaucoma suspect eyes with a history of DH should be carefully followed after IOP-lowering procedures. Additional IOP-lowering may be needed to slow structural progression of the DH eyes to the same rate as the non-DH eyes.

Elevated Intraocular Pressure Causes Abnormal Reactivity of Mouse Retinal Arterioles

Objective

Glaucoma is a leading cause of severe visual impairment and blindness. Although high intraocular pressure (IOP) is an established risk factor for the disease, the role of abnormal ocular vessel function in the pathophysiology of glaucoma gains more and more attention. We tested the hypothesis that elevated intraocular pressure (IOP) causes vascular dysfunction in the retina.

Methods

High IOP was induced in one group of mice by unilateral cauterization of three episcleral veins. The other group received sham surgery only. Two weeks later, retinal vascular preparations were studied by video microscopy in vitro. Reactive oxygen species (ROS) levels and expression of hypoxia markers and of prooxidant and antioxidant redox genes as well as of inflammatory cytokines were determined.

Results

Strikingly, responses of retinal arterioles to stepwise elevation of perfusion pressure were impaired in the high-IOP group. Moreover, vasodilation responses to the endothelium-dependent vasodilator, acetylcholine, were markedly reduced in mice with elevated IOP, while no differences were seen in response to the endothelium-independent nitric oxide donor, sodium nitroprusside. Remarkably, ROS levels were increased in the retinal ganglion cell layer including blood vessels. Expression of the NADPH oxidase isoform, NOX2, and of the inflammatory cytokine, TNF-α, was increased at the mRNA level in retinal explants. Expression of NOX2, but not of the hypoxic markers, HIF-1α and VEGF-A, was increased in the retinal ganglion cell layer and in retinal blood vessels at the protein level.

Conclusion

Our data provide first-time evidence that IOP elevation impairs autoregulation and induces endothelial dysfunction in mouse retinal arterioles. Oxidative stress and inflammation, but not hypoxia, appear to be involved in this process.

Elucidation of the Strongest Factors Influencing Rapid Retinal Nerve Fiber Layer Thinning in Glaucoma

Purpose

To determine which groupings of prognostic factors best explain the rapid progressive retinal nerve fiber layer (RNFL) thinning in patients with primary open-angle glaucoma (POAG).

Methods

Optic nerves of 111 POAG patients who were followed for at least 2.5 years, during which the RNFL thickness was measured by serial spectral-domain optical coherence tomography (OCT) were included. Eyes were imaged using enhanced depth-imaging spectral-domain OCT and swept-source OCT angiography to determine the lamina cribrosa curvature index (LCCI), and the presence of a choroidal microvasculature dropout (cMvD), respectively. The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements. A regression tree model was used to find groupings of factors that best explain the rate of future RNFL thinning.

Results

Disc hemorrhage, larger LCCI, and presence of cMvD were associated with faster global RNFL thinning in the multivariate regression analysis. The regression tree analysis revealed three stratified groups based on the rate of RNFL thinning, divided by the LCCI and the presence of cMvD. Eyes with LCCI ≥11.87 had the fastest RNFL thinning (-2.4 ± 0.8 μm/year, mean ± SD). Among eyes with LCCI <11.87, the presence of cMvD was the strongest factor influencing faster RNFL thinning (-1.5 ± 0.8 μm/year). Eyes with LCCI <11.87 and without a cMvD exhibited the slowest RNFL thinning (-0.8 ± 0.9 μm/year).

Conclusions

Our regression tree model demonstrated that larger LCCI, and then the presence of cMvD were the first and second strongest prognostic factors for faster progressive RNFL thinning. Further studies may be needed to confirm these findings.

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.

Influence of Choroidal Microvasculature Dropout on the Rate of Glaucomatous Progression: A Prospective Study

PURPOSE

To determine the prognostic significance of choroidal microvasculature dropout (MvD) to predict the future rate of progressive retinal nerve fiber layer (RNFL) thinning in eyes with primary open-angle glaucoma (POAG).

DESIGN

Prospective, longitudinal case series.

PARTICIPANTS

This study enrolled 101 eyes of 101 patients with POAG who underwent OCT angiography (OCTA) imaging of the optic nerve head at baseline and were followed up for at least 2 years thereafter, during which RNFL thickness was measured by serial spectral-domain OCT.

METHODS

The peripapillary microvasculature was evaluated by examining en face OCTA images. Choroidal MvD was defined as a focal sectoral capillary dropout with no visible microvascular network in the choroidal layer. The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements.

MAIN OUTCOME MEASURES

Influence of the presence of an MvD on the rate of subsequent RNFL thinning.

RESULTS

Microvasculature dropout was identified in 48 eyes (47.5%). The rate of global RNFL thinning was significantly faster in eyes with MvD than eyes without MvD (-1.6±0.8 vs. -1.2±0.9 μm/year, P = 0.018). Eyes with MvD in the inferior hemisphere (n = 41) showed a faster rate of inferior RNFL thinning than eyes without MvD (P = 0.036). Eyes with MvD in both the superior and inferior hemispheres (n = 5) showed faster rates of superior (P = 0.027) and inferior (P = 0.016) RNFL thinning than eyes without MvD. Multivariate regression analysis showed that MvD at baseline (P = 0.003) and the presence of disc hemorrhage during follow-up (P = 0.001) were independently associated with a faster rate of global RNFL thinning.

CONCLUSIONS

Microvasculature dropout was an independent predictor of a faster rate of progressive RNFL thinning in patients with POAG. Microvasculature dropout location was topographically associated with the location of faster RNFL thinning.

Location of Disc Hemorrhage and Direction of Progression in Glaucomatous Retinal Nerve Fiber Layer Defects

PURPOSE

To investigate the relationship between glaucomatous disc hemorrhage (DH) location with respect to the nasal or temporal margin of the retinal nerve fiber layer defect (RNFLD) and the direction of RNFLD widening.

MATERIALS AND METHODS

This is a retrospective, cross-sectional study. Patients with any documented episode of glaucomatous DH throughout the follow-up period, and definite RNFLD widening on retinal nerve fiber layer photographs were analyzed. The location of DH was recorded as either nasal or temporal, and the direction of RNFLD widening was investigated. The laterality of DH location on the RNFLD border and the direction of RNFLD widening were correlated with each other. We also compared clinical parameters between eyes with nasal versus temporal margin DHs.

RESULTS

We analyzed 123 eyes from 116 patients with definite widening of the RNFLD and glaucomatous DH at the border between the healthy and damaged retinal nerve fiber layer. The most common diagnosis was normal-tension glaucoma (109, 87.9%). The most frequent location of DH was the temporal margin of an inferotemporal RNFLD (75, 61.0%), and the most frequent pattern of change in RNFLD was temporal widening (89, 72.4%). The absolute congruency was 82.9% and the total congruency was 99.2%. No significant differences were identified between eyes with nasal versus temporal margin DHs.

CONCLUSIONS

The lateral location of DH on the RNFLD border was highly congruent with the direction of RNFLD widening. This correspondence of laterality between DH development and progression of RNFLD may suggest an intimate structural relationship during the pathogenesis of DH, at the enlarging RNFLD border.

Optic Nerve Head Astrocytes Display Axon-Dependent and -Independent Reactivity in Response to Acutely Elevated Intraocular Pressure

Purpose

Optic nerve head (ONH) astrocytes provide support for axons, but exhibit structural and functional changes (termed reactivity) in a number of glaucoma models. The purpose of this study was to determine if ONH astrocyte structural reactivity is axon-dependent.

Methods

Using rats, we combine retrobulbar optic nerve transection (ONT) with acute controlled elevation of intraocular pressure (CEI), to induce total optic nerve axon loss and ONH astrocyte reactivity, respectively. Animals were euthanized immediately or 1 day post CEI, in the presence or absence of ONT. ONH sections were labeled with fluorescent-tagged phalloidin and antibodies against β3 tubulin, phosphorylated cortactin, phosphorylated paxillin, or complement C3. ONH label intensities were quantified after confocal microscopy. Retrobulbar nerves were assessed for axon injury by light microscopy.

Results

While ONT alone had no effect on ONH astrocyte structural orientation, astrocytes demonstrated significant reorganization of cellular extensions within hours after CEI, even when combined with ONT. However, ONH astrocytes displayed differential intensities of actin (phosphorylated cortactin) and focal adhesion (phosphorylated paxillin) mediators in response to CEI alone, ONT alone, or the combination of CEI and ONT. Lastly, label intensities of complement C3 within the ONH were unchanged in eyes subjected to CEI alone, ONT alone, or the combination of CEI and ONT, relative to controls.

Conclusions

Early ONH astrocyte structural reactivity to elevated IOP is multifaceted, displaying both axon dependent and independent responses. These findings have important implications for pursuing astrocytes as diagnostic and therapeutic targets in neurodegenerative disorders with fluctuating levels of axon injury.

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.

Factors associated with the presence of parafoveal scotoma in glaucomatous eyes with optic disc hemorrhages

PURPOSE

Glaucomatous eyes with disc hemorrhage (DH) have a greater risk of paracentral visual field (VF) loss. However, not every DH eye presents with parafoveal scotoma (PFS), and contributing factors are still to be determined. In the present study, we investigated clinical and ocular factors associated with the presence of PFS in glaucomatous eyes with DH.

METHODS

A case-control study was carried out. One hundred thirty glaucomatous patients with DH were enrolled. They were divided into two groups based on two reliable 24-2 VF tests: those with PFS (defined as ≥3 adjacent points with p < 5% within the central 10 degrees of fixation, ≥1 point with p < 1% lying at the innermost paracentral points, in the same hemifield) and those without PFS. Clinical and ocular data from the time of DH detection were compared between groups. Factors associated with the presence of PFS were investigated through logistic regression.

RESULTS

The PFS group had a higher prevalence of Caucasian patients (82 vs. 47%; p < 0.01). Eyes with PFS had a more negative spherical equivalent and worse VF mean deviation (MD) index (p ≤ 0.01). There was a marginally significant intraocular pressure (IOP) difference between eyes with (15 mmHg) and without PFS (18 mmHg) at the time of DH detection (p = 0.10). Univariable analysis revealed PFS to be significantly associated with Caucasian race (OR, 3.02; p = 0.004), myopia (<-3 diopters; OR, 3.44; p = 0.039), and lower IOP (≤16 mmHg; OR, 2.10; p ≤ 0.047). Multivariable analysis, controlling for VF MD, revealed that only Caucasian race and myopia (as a continuous or categorical variable) remained significant in this model (p ≤ 0.038).

CONCLUSIONS

Caucasian race and the presence and magnitude of myopia were found to be significantly associated with the presence of PFS in glaucomatous eyes with DH. Our results may help clinicians in the identification and surveillance of these eyes at higher risk of central VF loss.

Long-term follow-up of retinal nerve fiber layer cleavages in glaucoma patients and suspects

PURPOSE

To investigate the structural and functional characteristics and change of the retinal nerve fiber layer cleavages (RNFLCs) in glaucoma patients and suspects in long-term follow-up.

METHODS

This is a retrospective longitudinal study. Within 43 eyes of 30 subjects, 62 RNFLC locations were detected on color fundus photography. Basic ophthalmic examinations, color fundus photography, optical coherence tomography (OCT), and visual field (VF) test were performed in 6-month intervals. Clinical characteristics and the structural and functional changes of the cleaved areas were analyzed.

RESULTS

RNFLC and localized vitreoretinal traction occurred most commonly along the superotemporal retinal vessel arcade. Nine locations had corresponding defects on OCT deviation map, while 31 locations were associated with defects on OCT deviation map. Three locations had corresponding VF defects. More of the non-highly myopic eyes had lamellar hole than the highly myopes (p = 0.038). The RNFLC lesions in glaucomatous eyes were more frequently associated with OCT defects on deviation map (p = 0.021). There was no difference in the presence of lamellar hole or the number of RNFLCs between the glaucomatous and non-glaucomatous eyes. During a 66.8 ± 37.8-month follow-up, there was no structural or functional progression of the RNFLCs as determined by color fundus photography, VF test, and GPA of OCT interpreted by three ophthalmologists. There was no statistically significant change of RNFLC area (p = 0.268).

CONCLUSIONS

RNFLC did not show detectable functional or structural change in early glaucoma patients and suspects after long-term follow-up.

Fundus Densitometry Findings Suggest Optic Disc Hemorrhages in Primary Open-Angle Glaucoma Have an Arterial Origin

PURPOSE

To analyze optic disc hemorrhages (DH) associated with primary open-angle glaucoma by quantifying their geometric profile and comparing their densitometry with hemorrhages from retinal vein occlusions (RVO) and retinal macroaneurysms (MA), which have venous and arterial sources of bleeding, respectively.

DESIGN

Retrospective cross-sectional study.

METHODS

Setting: Massachusetts Eye & Ear.

POPULATION

Fundus images of DH (n = 40), MA (n = 14), and RVO (n = 25) were identified. Patient clinical backgrounds and demographics were obtained.

MAIN OUTCOME MEASURES

Grayscale pixel intensity units of hemorrhages and adjacent arteriole and venule over the same background tissue were measured. Densitometry differentials (arteriole or venule minus hemorrhage [ΔA and ΔV, respectively]) were calculated. The ratios of length (radial) to midpoint width for DH were calculated. Mean ΔA and ΔV between groups were compared with t tests. Multiple linear regression assessed the relation of retinal hemorrhage diagnosis to ΔA and ΔV and of DH shape to ΔA and ΔV.

RESULTS

Mean (± standard deviation) ΔA and ΔV for DH (6.9 ± 7.1 and -4.7 ± 8.0 pixel intensity units, respectively) and MA (5.3 ± 5.9 and -6.0 ± 4.6, respectively) were comparable (P ≥ .43). Mean ΔA (14.6 ± 7.7) and ΔV (6.4 ± 6.3) for RVO were significantly higher compared to DH and MA (P < .0001) and remained significant in multivariable analyses. A unit increase in DH length-to-width ratio was associated with 1.2 (0.5) and 1.3 (0.5) pixel intensity unit (standard error) decrease in ΔA and ΔV, respectively (P ≤ .014).

CONCLUSIONS

DH have densitometry profiles comparable to MA and different from RVO, suggesting that DH in glaucoma have an arterial origin.