What is the link between vascular dysregulation and glaucoma?

Sodium-Glucose Cotransporter 2 Inhibitors for the Primary Prevention of Glaucoma in Patients With Type 2 Diabetes: A Target Trial Emulation

PURPOSE

Pleiotropic cardiovascular benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) due to vascular remodeling effects have been demonstrated in patients with type 2 diabetes mellitus. It is unclear whether a similar benefit may be seen for glaucoma. The purpose of this study was to assess the effect of SGLT2i on the risk of glaucoma in patients with type 2 diabetes.

DESIGN

Target trial emulation using observational data from multiple healthcare organizations.

METHODS

This population-based cohort study included adults with type 2 diabetes in the United States who newly initiated treatment with SGLT2i, dipeptidyl peptidase 4 inhibitors (DPP4i), or glucagon-like peptide-1 receptor agonists (GLP1RA) between 2013 and 2023. Propensity score matching was conducted to control for sociodemographic characteristics comorbidities, and concomitant use of medications. The exposure considered was treatment with SGLT2i for type 2 diabetes, and the outcomes were new-onset glaucoma and its subtypes after initiation of antidiabetic treatments. Subgroup analyses were performed to evaluate the effect of individual SGLT2i on incident glaucoma.

RESULTS

After propensity score matching, 722,446 patients were included in the SGLT2i arm and the DPP4i arm, respectively. Patients on SGLT2i, compared with those on DPP4i, had a lower risk of glaucoma (hazard ratio [HR] 0.815, 95% confidence interval [CI] 0.794, 0.837), including open-angle glaucoma (HR 0.755, 95% CI 0.729, 0.781) and primary angle-closure glaucoma (HR 0.702, 95% CI 0.636, 0.781). Among all SGLT2i, ertugliflozin (HR 0.668, 95% CI 0.512, 0.871) was associated with the lowest risk of glaucoma, followed by empagliflozin (HR 0.727, 95% CI 0.696, 0.759), dapagliflozin (HR 0.814, 95% CI 0.774, 0.855), and canagliflozin (HR 0.893, 95% CI 0.862, 0.926). The protective effect of SGLT2i on glaucoma was validated when compared with GLP1RA (HR 0.932, 95% CI 0.906, 0.959).

CONCLUSIONS

Patients on SGLT2i, including canagliflozin, empagliflozin, dapagliflozin, and ertugliflozin, had a significantly lower risk of incident glaucoma compared to those on DPP4i. SGLT2i demonstrated a protective effect for both open-angle glaucoma and angle-closure glaucoma.

Relationship Between Retinal Oxygen Saturation and the Severity of Visual Field Damage in Glaucoma

PRCIS

Increased oxygen saturation (StO 2 ) was significantly associated with the severity of visual field (VF) damage in patients with glaucoma.

OBJECTIVE

To investigate the association between retinal StO 2 percentage and the severity of VF loss in glaucoma.

METHODS

A total of 198 eyes from 131 patients with glaucoma were included in this cross-sectional study. Participants underwent imaging using ocular oximetry (Zilia) and 24-2 Swedish Interactive Threshold Algorithm standard VF (Carl Zeiss-Meditec). StO 2 (%) was measured at 2 locations of the peripapillary optic nerve head (superotemporal, and inferotemporal). Measurements were reported as the mean of at least 5 measurements in each location. Associations between the severity of VF loss, reported as mean deviation, and StO 2 (%) were calculated.

RESULTS

A total of 198 eyes of 131 patients (mean (95% CI) age, 71.1 (68.9,73.3) years, 68 females (51.9%), and 63 males (48.1%) were analyzed. In univariable analysis, higher StO 2 -0.06 (-0.12, 0.00) was associated with severity in all hemifields ( P = 0.047). Multivariate regression analysis showed that each 1% increase in StO 2 was associated with -0.06 (-0.12, -0.00) dB loss in mean deviation in all hemifields ( P = 0.043). In multivariate regression analysis in the superior hemifields, higher StO 2 -0.07 (-0.16, 0.01) tended to be associated with superior hemifield severity ( P = 0.09).

CONCLUSIONS

Retinal oximetry enabled the continuous quantitative measurement of retinal StO 2. Increased StO 2 was significantly associated with the severity of VF damage in patients with glaucoma.

A Randomized, Controlled Comparison of NCX 470, a Nitric Oxide-Donating Bimatoprost, and Latanoprost in Subjects with Open-Angle Glaucoma or Ocular Hypertension: The MONT BLANC Study

PURPOSE

To compare intraocular pressure (IOP)-lowering efficacy and safety of NCX 470, a nitric oxide (NO)-donating bimatoprost, to latanoprost in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Prospective, phase 3, randomized, adaptive dose-selection, double-masked, parallel-group trial.

METHODS

691 subjects with OAG or OHT and unmedicated IOP ≥26 mmHg at 8AM, ≥24 mmHg at 10AM, and ≥22 mmHg at 4PM in the study eye were randomized to NCX 470 0.065%, NCX 470 0.1%, or latanoprost 0.005%. An interim analysis was performed to select the final dose of NCX 470. We evaluated noninferiority of NCX 470 versus latanoprost, based on IOP reduction from baseline at 8AM and 4PM at 2 weeks, 6 weeks, and 3 months.

RESULTS

661 subjects were analyzed; IOP was significantly reduced at all on-treatment time points, with reductions ranging from 8.0 to 9.7 mmHg (P < .0001 at each time point) in the NCX 470 0.1% group. Mean IOP reductions were greater with NCX 470 0.1% than latanoprost 0.005% at all 6 time points and significantly greater (P < .05) at 4 of the 6 time points. The most common adverse event was conjunctival/ocular hyperemia.

CONCLUSION

The NO-donating prostaglandin analogue NCX 470 0.1% was well-tolerated and lowered IOP more than latanoprost in subjects with OAG or OHT at all 6 time points. With a dual mechanism of action that enhances both uveoscleral and trabecular outflow, NCX 470 could become an important first-line therapy for IOP reduction in glaucoma.

Quantitative evaluation of OCT angiography images in healthy and glaucomatous subjects through a novel approach: exploring inter-image variability

PURPOSE

This study aims to investigate inter-image intra-observer variability of macular, and optic disc (ONH) microvasculature measurements of glaucomatous and normal subjects using Swept-Source Optical Coherence Tomography Angiography (OCT-A) (OCT Topcon ImageNet 6; DRI OCT Triton, Topcon Corporation, JAPAN) - based imaging data analysis and processing with a newly made quantitative approach.

METHODS

A total of 20 glaucomatous and 20 healthy eyes underwent three OCT-A scanning of the ONH and macula. Macular and papillary and peripapillary vascular networks were calculated. For each eye, eighteen scans were analyzed using a novel approach: custom MATLAB 2021b scripts were employed for imaging analyses. Grayscale distribution was performed using the histcounts MATLAB function with 51 bins. For all layers, the vascular layer coefficient of variation (vl CoV) of the three measures were performed. The vl CoV difference between the two groups was analyzed by Student t-test.

RESULTS

In glaucomatous eyes, the vl CoV ranged from 4.49% to 8.54%, while in the control group from 3.58% to 8.32%. Both groups exhibited higher CoVs when assessing the optic disc. The papillary and macular microvasculature reproducibility was comparable between groups.

CONCLUSIONS

Utilizing Swept-Source OCT-A images our study has identified an easy and reproducible method that appears to be fast and can assist physicians in assessing macular and ONH perfusion with less inter-image variability, particularly in the 70 μm superficial area of the optic disc. The high reliability obtained suggested that this method could be useful as early clinical biomarker.

Macula vessel density and its relationship with the central visual field mean sensitivity across different stages of exfoliation glaucoma

CLINICAL RELEVANCE

Alterations in ocular microvasculature may contribute to pathogenesis of exfoliation glaucoma (XFG) and may improve monitoring this aggressive type of open angle glaucoma.

BACKGROUND

This work aims to compare the macula vessel density and the relationship between macula vessel density and central visual field mean sensitivity between eyes with XFG and eyes with primary open-angle glaucoma (POAG) of different stages.

METHODS

In this cross-sectional observational study, the macula vessel density values were compared among 52 POAG cases (26 early stage, 26 moderate to advanced stage) and 53 XFG cases (27 early stage, 26 moderate to advanced stage). The vessel density values were evaluated with optical coherence tomography angiography. Vasculature-function and structure-function relationships were analysed by comparing macula vessel density, inner macula thickness and visual field mean sensitivity in early and moderate to advanced stages of XFG and POAG eyes separately.

RESULTS

The early stage XFG eyes had a significantly lower global macula vessel density compared with early stage POAG eyes (42.81 ± 3.85% and 46.56 ± 3.90%, respectively; p = 0.02). However, the tendency of XFG eyes for a lower vessel density compared with the POAG eyes did not exhibit any significance in moderate to advanced stages of glaucoma (37.39 ± 5.65% and 38.35 ± 4.67%, respectively; p = 0.9). The macula vessel density (%)-visual field mean sensitivity (1/Lambert) correlation was statistically significant in early stage XFG eyes (r = 0.464 p = 0.01), while no such correlation was notable for the early stage POAG eyes (r = -0.029 p = 0.89).

CONCLUSION

The macula vessel density appears to be more severely affected in early stage XFG than POAG of similar severity, suggesting a relatively greater value of vascular insufficiency in XFG. The significant vasculature-function association in early stage XFG, which was absent in early stage POAG, may infer the importance of macula vessel density in monitoring functional loss in early stages of XFG.

The effect of systemic sclerosis and its subtypes on ocular anterior and posterior segment parameters

PURPOSE

To evaluate anterior and posterior segment parameters in the eyes of patients with systemic sclerosis (SSc) and examine the effect of disease and disease subtypes on these parameters.

METHODS

This cross-sectional study included 54 eyes of 27 SSc patients and 54 eyes of 27 age- and sex-matched healthy controls. In addition to a complete ophthalmologic examination, all patients were examined using a Scheimpflug camera, specular microscopy, and spectral domain optical coherence tomography.

RESULTS

The mean age of the patients was 52.5 ± 11.4 years and 19 patients were female. Anterior chamber volume, central corneal thickness, and central macular thickness (CMT) were significantly lower in the eyes of SSc patients compared to healthy controls (p = 0.01, p = 0.03, and p = 0.006, respectively). When evaluated according to SSc subtype, CMT was lower in diffuse SSc patients (p = 0.001), while mean retinal nerve fiber layer (RNFL) and inferior quadrant RNFL values were lower in limited SSc (p = 0.003 and p = 0.005, respectively).

CONCLUSION

In the eyes of patients with SSc, some ocular parameters may show decreases compared to healthy individuals, presumably secondary to disease-related vasculopathy and fibrosis. CMT and RNFL parameters may be affected differently according to disease subtype.

Unveiling the silent link: Normal-tension glaucoma's enigmatic bond with cardiac blood flow

This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma (NTG), a condition that continues to baffle clinicians and researchers alike. NTG, characterized by optic nerve damage and visual field loss despite normal intraocular pressure, has long puzzled clinicians. One emerging perspective suggests that alterations in ocular blood flow, particularly within the optic nerve head, may play a pivotal role in its pathogenesis. While NTG shares commonalities with its high-tension counterpart, its unique pathogenesis and potential ties to cardiovascular health make it a fascinating subject of exploration. It navigates through the complex web of vascular dysregulation, blood pressure and perfusion pressure, neurovascular coupling, and oxidative stress, seeking to uncover the hidden threads that tie the heart and eyes together in NTG. This review explores into the intricate mechanisms connecting cardiovascular factors to NTG, shedding light on how cardiac dynamics can influence ocular health, particularly in cases where intraocular pressure remains within the normal range. NTG's enigmatic nature, often characterized by seemingly contradictory risk factors and clinical profiles, underscores the need for a holistic approach to patient care. Drawing parallels to cardiac health, we examine into the shared vascular terrain connecting the heart and the eyes. Cardiovascular factors, including systemic blood flow, endothelial dysfunction, and microcirculatory anomalies, may exert a profound influence on ocular perfusion, impacting the delicate balance within the optic nerve head. By elucidating the subtle clues and potential associations between cardiology and NTG, this review invites clinicians to consider a broader perspective in their evaluation and management of this elusive condition. As the understanding of these connections evolves, so too may the prospects for early diagnosis and tailored interventions, ultimately enhancing the quality of life for those living with NTG.

The Role of Retinal Ganglion Cell Structure and Function in Glaucoma

Glaucoma, a leading cause of irreversible blindness globally, primarily affects retinal ganglion cells (RGCs). This review dives into the anatomy of RGC subtypes, covering the different underlying theoretical mechanisms that lead to RGC susceptibility in glaucoma, including mechanical, vascular, excitotoxicity, and neurotrophic factor deficiency, as well as oxidative stress and inflammation. Furthermore, we examined numerous imaging methods and functional assessments to gain insight into RGC health. Finally, we investigated the current possible neuroprotective targets for RGCs that could help with future glaucoma research and management.

Evaluation of retinal microvascular network in patients with systemic sclerosis: An optical cohorence tomography angiography study

PURPOSE

To investigate the long-term effect of systemic sclerosis on the optic disk and retinal capillary network and to see whether the drugs used in the treatment of SSc affected optical coherence tomography angiography (OCTA) parameters.

MATERIALS AND METHODS

This cross-sectional case-control study included 40 systemic sclerosis patients and 40 healthy individuals. We included only one eye of each patient in the study. Macular layers and angiography scanning were performed with a Zeiss Cirrus 5000 OCTA system. Such values as macular thickness, retinal nerve fiber layer (RNFL), ganglion cell inner plexiform layer (GC-IPL) were obtained. For central vessel and perfusion density (VD, PD), central 6 mm were obtained and were evaluated by dividing it into 3 groups as inner, outer, and full. The FAZ was evaluated through 3 parameters: area, perimeter, circularity index.

RESULTS

Statistically significant difference was found between the groups in terms of the mean and foveal macular thickness values (p=0.008, p=0.033). Significant differences were also found between the two groups in terms of the VD and PD parameters in all regions except for 1 mm center (p<0.05). There were no significant differences in RNFL and GC-IPL values between two groups. Also, a positive correlation was observed between parapapillary perfusion density values and RNFL and GC-IPL thicknesses in SSc group. When the subgroups were compared in terms of vasodilator drug use, the subgroup using vasodilators was seen to have higher mean RNFL and inferior RNFL thicknesses (p=0.045 and p=0.035, respectively). In addition, there was a significant positive correlation between parapapillary VD and RNFL values in the SSc subgroup treated with vasodilators.

CONCLUSIONS

The results of this study demonstrate microvascular loss in individuals with systemic sclerosis, compared with healthy subjects. Also, it has been determined that OCTA is an important test for screening retinal and optic disk microvascular changes over time in cases of systemic sclerosis and may be used to evaluate the response to vasodilator drugs used in the treatment of SSc disease.

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.

Evaluation of the Optic Nerve Head Using Optical Coherence Tomography Angiography in Systemic Sclerosis Patients

PURPOSE

To quantify microvascular vessel density in the optic disc using optical coherence tomography angiography (OCTA) in patients with systemic sclerosis (SS); to determine whether there is a difference in values between patients and controls; and to correlate the OCTA measurements with disease activity, damage risk, and drug usage.

METHODS

Patients aged 20 - 76 years who were followed up after a diagnosis of SS and age- and gender-matched controls. The patients underwent RTVue-XR AngioVue OCTA imaging in this cross-sectional observational study.

RESULTS

A total of 61 eyes of 61 consecutive SS patients and 60 eyes of 60 controls were investigated. There was no statistically significant difference between the patients and control groups regarding the average RNFL (retinal fiber layer) and radial peripapillary capillary (RPC) vessel density (VD) measurements (p = 0.35, p = 0.25, respectively). As the antinuclear antibody (ANA) titer increased, RNFLsuperior (p = 0.01, r = - 0.327), RPCwhole (p = 0.029, r = 0.279), RPCperipapillary (p = 0.037, r = - 0.267), RPCsuperior (p = 0.003, r = - 0.371), and RPCinferior (p = 0.02, r = 0.297) values decreased with statistical significance. The RPCinside values were lower in anti-Scl-70-positive patients compared to patients negative for anti-Scl-70 (topoisomerase I) (p = 0.021). The RNFLnasal (p = 0.03, r = - 0.278) value decreased as the years of disease increased. The RPCinside value was higher in patients using hydroxychloroquine and calcium channel blockers than those who did not use them (p = 0.021 and p = 0.027, respectively). The RPCwhole, RPCperipapillary, and RPCnasal values were higher, with statistical significance in corticosteroid users than in those patients who did not use corticosteroids (p = 0.043, 0.030, and 0.033, respectively).

CONCLUSION

There was no significant difference between the patients and control groups regarding the average RPC VD measurements. However, since this is the first study to analyze optic disc vessel density in SS patients, optic nerve blood flow changes in scleroderma with OCTA could be studied.

Complement System Proteins in the Human Aqueous Humor and Their Association with Primary Open-Angle Glaucoma

This study discovers the complement protein profile in the aqueous humor (AH) of human subjects and investigates its association with primary open-angle glaucoma (POAG) pathogenesis. Among the 32 complement proteins identified, 22 were highly abundant and detected in more than 50% of AH samples. The most predominant active complement proteins in the AH are C3, C4B, C4A, CFB, CFD, and C9. Additionally, the most prevalent complement regulators and receptors include CLU, SERPING1, F2, CFH, CFI, and VTN. Significant alterations in complement proteins were observed in individuals with POAG compared to those with cataracts. Specifically, complement protein F2 was upregulated, while C8G, C6, and CFH were downregulated in POAG samples. Stratification of the samples by race and sex revealed distinct alterations of complement proteins in patients with POAG. In the African American cohort, five complement proteins (C4A, C4B, F2, C7, and C3) were upregulated in POAG compared to cataract patients. In the Caucasian cohort, eight complement proteins (C3, SERPING1, CFI, CLU, CFHR1, C8G, C6, and CFH) were downregulated in the POAG samples compared to the cataract samples. Within the male cohort, three complement proteins (CLU, C6, and CFH) were downregulated in POAG patients compared to those with cataracts. Whereas, within the female cohort, two complement proteins (C4B and F2) were upregulated and one (C8G) downregulated in the POAG samples when compared to cataracts. Discerning these changes in the AH complement protein profile will assist in the development of tailored therapies to modulate the complement system for managing ocular disorders. These insights may also lead to novel biomarkers for diagnosing and monitoring disease progression.

Tear nanoDSF Denaturation Profile Is Predictive of Glaucoma

Primary open-angle glaucoma (POAG) is a frequent blindness-causing neurodegenerative disorder characterized by optic nerve and retinal ganglion cell damage most commonly due to a chronic increase in intraocular pressure. The preservation of visual function in patients critically depends on the timeliness of detection and treatment of the disease, which is challenging due to its asymptomatic course at early stages and lack of objective diagnostic approaches. Recent studies revealed that the pathophysiology of glaucoma includes complex metabolomic and proteomic alterations in the eye liquids, including tear fluid (TF). Although TF can be collected by a non-invasive procedure and may serve as a source of the appropriate biomarkers, its multi-omics analysis is technically sophisticated and unsuitable for clinical practice. In this study, we tested a novel concept of glaucoma diagnostics based on the rapid high-performance analysis of the TF proteome by differential scanning fluorimetry (nanoDSF). An examination of the thermal denaturation of TF proteins in a cohort of 311 ophthalmic patients revealed typical profiles, with two peaks exhibiting characteristic shifts in POAG. Clustering of the profiles according to peaks maxima allowed us to identify glaucoma in 70% of cases, while the employment of artificial intelligence (machine learning) algorithms reduced the amount of false-positive diagnoses to 13.5%. The POAG-associated alterations in the core TF proteins included an increase in the concentration of serum albumin, accompanied by a decrease in lysozyme C, lipocalin-1, and lactotransferrin contents. Unexpectedly, these changes were not the only factor affecting the observed denaturation profile shifts, which considerably depended on the presence of low-molecular-weight ligands of tear proteins, such as fatty acids and iron. Overall, we recognized the TF denaturation profile as a novel biomarker of glaucoma, which integrates proteomic, lipidomic, and metallomic alterations in tears, and monitoring of which could be adapted for rapid non-invasive screening of the disease in a clinical setting.

Results of Nailfold Videocapillaroscopy in Patients with Pseudoexfoliative Glaucoma

The aim of this study was to evaluate the nailfold videocapillaroscopic examination results from patients with pseudoexfoliative glaucoma (XFG) and to assess the relationship between the results of this examination and the patient's clinical status in the XFG group.

MATERIAL AND METHODS

The studied group consisted of 39 Caucasian patients with XFG and 32 patients in a control group. The patients were classified into two subgroups: the hypertensive pseudoexfoliative glaucoma (hXFG) subgroup and the normotensive pseudoexfoliative glaucoma (nXFG) subgroup. The nailfold videocapillaroscopy (NVC) was performed on all participants. The results of each NVC were classified as having a normal or abnormal pattern.

RESULTS

There was no statistical difference between the results of an abnormal NVC pattern in the study group vs. the control group (p = 0.8773). Microhemorrhages were shown in 30.0% of patients with nXFG vs. the control group (6.25%) (p = 0.0520). Microhemorrhages tended to be more frequent in the XFG group (p = 0.1221). A prevalent number of tortuous capillaries was observed in hXFG patients with advanced glaucomatous neuropathy. Dilatation in the capillaries and microbleedings were observed in the group of patients with lower IOP values. Tortuosity in the capillaries was significantly more frequent in PEXG patients (XFG vs. control: p = 0.0386). No relationships between the results of NVC and age, c/d, BCVA, time of treatment, and visual field defect were found.

CONCLUSIONS

Specific features of NVC examination differentiate nXFG from hXFG patients. Some capillaroscopic features may correlate with the patient's clinical status of XFG.

Vascular parameters and endothelin-1 measurements in glaucoma patients with low- and high-tension optic disc hemorrhages

This prospective study aimed to compare vascular parameters (endothelin-1 [ET-1] blood levels, laser Doppler imaging [LDI] of distal phalanxes, and nailfold capillaroscopy) between open-angle glaucoma patients with low- and high-tension optic disc hemorrhages (LTDH and HTDH, respectively). The 33 enrolled patients (mean age, 62.3 ± 13 years) were classified as LTDH or HTDH if they presented at the time of DH detection an intraocular pressure (IOP) < 16 mmHg or ≥ 16 mmHg, respectively. Demographic and ophthalmological data, ET-1 concentrations, LDI (before and 1, 10, and 20 min after cold stimulation), and nailfold capillaroscopy findings were evaluated. The ET-1 blood level was 65% higher in the LTDH (2.27 ± 1.46 pg/ml) than in the HTDH (1.37 ± 0.57 pg/ml; p = 0.03) group. Moreover, there was a statistically significant negative correlation between ET-1 blood concentration and IOP at the time of DH detection (r = -0.45, p = 0.02). Blood flow measurements 10 and 20 min after cold stimulation were lower in the LTDH group than in the HTDH group (p < 0.01). Patients developing DH with lower IOPs have higher ET-1 blood levels and more peripheral vascular dysfunction as estimated by LDI than those with higher IOPs. These findings suggest that distinct underlying mechanisms may be involved in patients developing DH within different IOP ranges.

OCTA and Doppler Ultrasound in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma

The aim of this study was to determine whether the values of vessel density (VD) and perfusion parameters in the ophthalmic artery (OA) and central retinal artery (CRA) of the same eye differ in patients with hypertensive glaucoma (HTG) from patients with normotensive glaucoma (NTG). The first group consisted of 20 HTG patients (40 eyes). Patients with HTG were verified to have primary open-angle glaucoma (POAG). The second group consisted of 20 HTG patients (40 eyes). VD was used to determine the Avanti RTVue XR from Optovue (USA). Peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI) were measured in both the central retinal artery (CRA) and ophthalmic artery (OA) using Doppler sonography on the Affinity 70G from Philips (USA). The visual field (VF) was examined by a fast threshold glaucoma program using a Medmont M700 (Australia). We showed no differences in VF, VD, PSV-OA and EDV-CRA between the two groups. Statistically significant differences between the two groups were observed in PSV in CRA (p = 0.04), EDV in OA (p = 0.009) and in RI in both CRA and OA. Other values were without significant differences in both groups. In both HTG and NTG, we observed in PSV-CRA, EDV-OA, RI-CRA and RI-OA.

Ocular decompression retinopathy following bleb needling in a young child

Ocular decompression retinopathy (ODR) is caused by a sudden lowering of high intraocular pressure. Trabeculectomy is the most common procedure preceding ODR. Various mechanical and vascular etiologies have been proposed to cause ODR, with autoregulation and hemodynamics playing a contributing role. Herein, we report a rare case of ODR occurring after bleb needling in a young child using ultrawide-field fundus photography, fluorescein angiography, and optical coherence tomography.

Evaluation of corneal biomechanical properties using the ocular response analyzer and the dynamic Scheimpflug-Analyzer Corvis ST in high pressure and normal pressure open-angle glaucoma patients

PURPOSE

To characterize differences in corneal biomechanics in high (HPG) and normal pressure (NPG) primary open-angle glaucoma, and its association to disease severity.

METHODS

Corneal biomechanical properties were measured using the Ocular Response Analyzer (ORA) and the dynamic Scheimpflug-Analyzer Corvis ST (CST). Disease severity was functionally assessed by automated perimetry (Humphrey field analyzer) and structurally with the Heidelberg Retina Tomograph. To avoid a possible falsification by intraocular pressure, central corneal thickness and age, which strongly influence ORA and CST measurements, group matching was performed. Linear mixed models and generalized estimating equations were used to consider inter-eye correlation.

RESULTS

Following group matching, 60 eyes of 38 HPG and 103 eyes of 60 NPG patients were included. ORA measurement revealed a higher CRF in HPG than in NPG (P < 0.001). Additionally, the CST parameter integrated radius (P < 0.001) was significantly different between HPG and NPG. The parameter SSI (P < 0.001) representing corneal stiffness was higher in HPG than in NPG. Furthermore, regression analysis revealed associations between biomechanical parameters and indicators of disease severity. In HPG, SSI correlated to RNFL thickness. In NPG, dependencies between biomechanical readings and rim area, MD, and PSD were shown.

CONCLUSION

Significant differences in corneal biomechanical properties were detectable between HPG and NPG patients which might indicate different pathophysiological mechanisms underlying in both entities. Moreover, biomechanical parameters correlated to functional and structural indices of diseases severity. A reduced corneal deformation measured by dynamic methods was associated to advanced glaucomatous damage.

Comparison of microvascular parameters and diagnostic ability of optical coherence tomography angiography between eyes with primary angle closure glaucoma and primary open angle glaucoma

BACKGROUND

To investigate and compare the peripapillary and macular microvascular parameters between eyes with primary angle closure glaucoma (PACG) and primary open-angle glaucoma (POAG) using optical coherence tomography angiography (OCTA).

METHODS

Seventy-nine eyes of 43 patients with primary angle closure glaucoma (PACG), 78 eyes of 43 patients with primary open-angle glaucoma (POAG), 64 eyes of 35 patients with primary angle closure (PAC), and 73 eyes of 40 control subjects underwent imaging with OCTA. Perfusion density (PD) and vessel density (VD) for the macular area, and PD and flux index (FI) for the peripapillary area were calculated automatically. The area under receiver operator characteristic curves (AUC) were constructed to distinguish PACG and POAG eyes from healthy control eyes.

RESULTS

The peripapillary FI in all quadrants and PD and VD of the macular outer circle in superior and inferior quadrants were significantly lower in PACG and POAG eyes than in control eyes. The peripapillary FI in the inferior quadrant was significantly lower in the POAG group than in the PACG group (0.348 ± 0.06 vs. 0.369 ± 0.06, p = 0.04). The remaining OCTA parameters in the peripapillary and macular area did not show a significant difference between the POAG and PACG groups. Eyes with PAC presented significantly lower PD and VD than healthy control eyes at the superior and inferior quadrant of the macular outer circle, while retinal nerve fiber layer and ganglion cell inner complex thickness were not significantly different from than control eyes. The best diagnostic parameter was peripapillary FI in both PACG (AUC: 0.922) and POAG (AUC: 0.938) eyes.

CONCLUSIONS

We found significantly lower peripapillary FI in the inferior quadrant in POAG eyes compared to the PACG eyes, which may indicate the different underlying pathogenesis between POAG and PACG. The PAC eyes had lower macular PD and VD than normal eyes. This suggests that retinal vascular impairment may develop earlier than structural damage in PAC eyes.

M. R, K. R. V, M. R. S, Gopi A. A cross-sectional study of association between ocular pressures and different grades of myopia in young adults

Introduction and Aim: My­opia is one of the most common refractive errors causing visual disability worldwide. Uncorrected refractive error poses a public health challenge especially in young adults who have to spend most of their time in literary works. Intra ocular pressure (IOP) is one of the crucial factors intertwined in the pathophysiology of myopia. Ocular perfusion pressure (OPP) determines ocular blood flow. Studies done on association between IOP and refractive errors are contradictory. There is paucity of literature on relationship between OPP and myopia. Hence this original article aimed to assess the association of IOP and OPP changes with myopia and to analyze the relationship between ocular pressures with severity of myopia.   Materials and Methods: Hundred normal adults in the age group of 18-24 years of either gender were recruited for the present study. Voluntary written and informed consent was sought from all participants and the refractive power of their eyes was noted. They were categorised into three groups based on the severity of myopia. Controls were the emmetropes. All participants were asked to relax for 5-10 minutes and the resting BP and IOP were recorded using sphygmomanometer and rebound tonometer respectively. OPP was calculated.   Results: IOP values were comparatively higher in myopes than emmetropes.  A significant reduction in OPP values were observed in moderate myopes.   Conclusion: Myopes have a higher IOP suggesting myopia is one of the major risk factor for ocular hypertension. Low OPP values in moderate myopes indicate reduced ocular perfusion, making the progressive myopes highly susceptible to glaucoma. 

Glaucoma and Alzheimer: Neurodegenerative disorders show an adrenergic dysbalance

Glaucoma disease is characterized by an increased intraocular pressure (IOP), glaucomatous alterations of the optic disc and corresponding visual field defects. Even lowering the main risk factor IOP until an individual target level does not prevent this neurodegenerative disorder from proceeding. Several autoimmune mechanisms were discovered, partly showing a functionality. One of these autoimmune phenomena targets the ß2-adrenergic receptor (ß2-AR; i.e. agonistic autoantibodies; ß2-agAAb) and is linked to an elevated IOP and an impaired retinal microcirculation. As neurodegenerative disorder, Alzheimer's Disease (AD) is postulated to share a common molecular mechanism with glaucoma. In the present study we investigated autoimmune phenomena targeting the ß2-AR in patients with AD. Sera of the patients were analyzed in a rat cardiomyocyte bioassay for the presence of functional autoantibodies against ß2-AR. In addition, different species of amyloid beta (Aß) monomers were tested (Aß1-14, Aß10-25, Aβ10-37 Aß1-40, Aß1-42, Aβ28-40, and Aß-[Pyr]3-43). Our results demonstrate that none of the short-chain Aß (Aß1-14, Aß10-25, or Aβ28-40) showed any agonistic or inhibitory effect on ß2-AR. Contrary, long-chain Aß-[Pyr]3-43, representing a major neurogenic plaque component, exerted an activation that after blocking by the ß2-AR antagonist ICI118.551, could be identified as that the effect was realized via the ß2-AR. Moreover, the long chain Aß1-40, Aβ1-42, and Aβ10-37, yet not the short-chain Aß peptides prevented the clenbuterol induced desensitization of the ß2-AR. In addition, we identified functional autoantibodies in the sera of AD patients, activating the ß2-AR, like the ß2-agAAb found in patients with glaucoma. As autoimmune mechanisms were reportedly involved in the pathogenesis of glaucoma and Alzheimer's Disease, we postulate that overstimulation of the ß2-AR pathway can induce an adrenergic overdrive, that may play an important role in the multifactorial interplay of neurodegenerative disorders.

Ocular and Systemic Factors Associated with Glaucoma

Glaucoma is one of the leading causes of irreversible blindness in the world. Although numerous factors have been implicated in the pathogenesis of glaucoma, the main focus of management still remains lowering the intraocular pressure (IOP) by medical or surgical therapy. However, a major challenge is that many glaucoma patients continue to progress despite good control of IOP. In this regard, the importance of other coexisting factors that may contribute to disease progression needs to be explored. Ophthalmologists need to be aware of ocular risk factors and the impact of systemic diseases and their medications, along with lifestyle modifications on the course of glaucomatous optic neuropathy and adopt a holistic approach in treating the eye as well as the patient to alleviate the suffering from glaucoma in a comprehensive manner.

How to cite this article

Dada T, Verma S, Gagrani M, et al. Ocular and Systemic Factors associated with Glaucoma. J Curr Glaucoma Pract 2022;16(3):179-191.

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.

Magnesium and Its Role in Primary Open Angle Glaucoma; A Novel Therapeutic?

Glaucoma is the leading cause of irreversible blindness globally, with Primary open angle glaucoma (POAG) being the commonest subtype. POAG is characterized by an increase in intraocular pressure (IOP), leading to optic nerve damage and subsequent visual field defects. Despite the clinical burden this disease poses, current therapies aim to reduce IOP rather than targeting the underling pathogenesis. Although the pathogenesis of POAG is complex, the culprit for this increase in IOP resides in the aqueous humour (AH) outflow pathway; the trabecular meshwork (TM) and Schlemm's canal. Dysfunction in these tissues is due to inherent mitochondrial dysfunction, calcium influx sensitivity, increase in reactive oxygen species (ROS) production, TGFβ-2 induction, leading to a sustained inflammatory response. Magnesium is the second most common intracellular cation, and is a major co-factor in over 300 reactions, being highly conserved within energy-dependent organelles such as the mitochondria. Magnesium deficiency has been observed in POAG and is linked to inflammatory and fibrotic responses, as well as increased oxidative stress (OS). Magnesium supplementation been shown to reduce cellular ROS, alleviate mitochondrial dysregulation and has further antifibrotic and anti-inflammatory properties within ocular tissues, and other soft tissues prone to fibrosis, suggesting that magnesium can improve visual fields in patients with POAG. The link between magnesium deficiency and glaucoma pathogenesis as well as the potential role of magnesium supplementation in the management of patients with POAG will be explored within this review.

Optic disc blood perfusion and oxygenation in glaucoma

Purpose

To investigate the haemoglobin concentration and oxygenation in the optic disc in glaucoma patients vs. controls.

Methods

Thirty-one eyes of primary open angle glaucoma patients (mean age: 64.9 ± 2.1 years) and 31 eyes of 31 healthy controls (65.5 ± 2.0 years) were included. Perimetry, optical coherence tomography (OCT), and OCT angiography were performed. Multispectral imaging was used to record the optic disc reflectance at wavelengths 522 nm, 548 nm, 555 nm, 586 nm, and 610 nm, and haemoglobin concentration and oxygenation (SO₂) were calculated from these measures. This was done in the rest and under stimulation of neuronal activity by flicker light.

Results

The haemoglobin concentration was significantly lower (p < 0.001) in the rim (40.0 ± 6.3) and the excavation (35.7 ± 8.0) of the glaucoma patients’ discs than in controls (45.7 ± 7.5). SO₂ was not different in general, but lower in a subgroup of 18 glaucoma patients with ischaemic disc rims than in non-ischaemic ones (median 26.8%, interquartile range (IQR): 29.5% vs. 51.9%, IQR 32.0%, p = 0.02) as well as in controls (41.0%, IQR 30.6%, p = 0.01). Flicker light stimulation significantly increased the haemoglobin concentration in the controls (+ 1.3 ± 3.6, p = 0.048) as well as in the rim of glaucoma discs (+ 2.6 ± 5.0, p = 0.006) and SO₂ in the controls only (+ 15.4 ± 23.6%, p = 0.001). The haemoglobin concentration was significantly correlated with the perimetric mean defect, retinal nerve fibre layer (RNFL) thickness and para-papillary perfusion density.

Conclusions

The optic disc haemoglobin concentration and oxygenation are quantifiable from multispectral imaging and reduced in glaucoma. The correlation of haemoglobin concentration with perfusion density, RNFL thickness and visual field loss indicates its implication in glaucoma pathology.

Study of normal-tension glaucoma based on OCTA and VBM-DARTEL analysis

The aim of the present study was to investigate the detection value of optical coherence tomography angiography (OCTA) and voxel-based morphometry with diffeomorphic anatomical registration through exponentiated lie algebra (VBM-DARTEL) in normal-tension glaucoma (NTG), as well as the correlation between the two functional indicators. A total of 30 patients (15 males, 15 females) with NTG and 30 (15 males, 15 females) age-, sex- and education-matched healthy controls underwent OCTA and 3.0 T MRI scanning. The OCTA technique was used to scan the optic disc area of all subjects and measure the density of blood vessels around the optic disc; 3.0 T MRI scanning was used to obtain MRI images of the brain structure and the VBM-DARTEL method was applied for image processing using Matlab7.11R2010b (MathWorks). Imaging data were compared between the groups using two-samples t-tests to identify differences in the density of blood vessels around the optic disc and the change in brain parenchyma. Correlation analysis was used to explore associations between the density of blood vessels around the optic disc and the change in brain parenchyma in NTG. The results indicated that the vascular density around the optic disc in the NTG group was significantly decreased compared with that in the control group; the vascular density was decreased with disease progression. The difference between the two groups was statistically significant (P<0.05). The VBM-DARTEL analysis indicated that the volume of the left middle frontal gyrus, right superior frontal gyrus, right precuneus, right angular gyrus and right middle occipital gyrus was decreased, whereas the volume of the right anterior central gyrus was increased. The area under the receiver operating characteristic curve for the local volume difference in brain parenchyma to predict the diagnosis of NTG was >0.7. The area of brain parenchyma reduction was positively correlated with the density of blood vessels around the optic disc (P<0.05), whereas the right anterior central gyrus was negatively correlated with vascular density. In conclusion, OCTA and VBM-DARTEL technology may facilitate non-invasive monitoring of changes in NTG structure and function, and provide non-invasive diagnostic imaging support in the early stage of the disease. These advantages are of great importance in the diagnosis and follow-up of NTG.

Evaluation of the radial peripapillary capillary density in unilateral branch retinal vein occlusion and the unaffected fellow eyes

Background:

Given that unilateral branch retinal vein occlusion (BRVO) and glaucoma share common systemic vascular risk factors, the fellow eyes of patients with BRVO may be at increased risk of glaucoma.

Objectives:

To analyze the radial peripapillary capillary density (RPCD) in eyes with unilateral BRVO and their unaffected fellow eyes using optical coherence tomography angiography (OCTA).

Design:

Cross-sectional, prospective study.

Methods:

The study included 120 eyes of 80 patients: 40 affected eyes of BRVO, 40 fellow eyes of BRVO, and 40 control eyes. The RPCD, retinal nerve fiber layer thickness (RNFLT) were analyzed using OCTA.

Results:

RPCDs in the whole image, peripapillary region, all the hemispheres, and quadrants were statistically lower in the affected eyes than in both the fellow and control eyes ( p < 0.05 for all). RPCD values in the whole image and the peripapillary region were significantly lower in the fellow eyes than in the control eyes ( p = 0.013, and p = 0.021, respectively). RNFLTs in the peripapillary region, inferior hemisphere and inferior quadrant were significantly lower in the affected eyes than in the control eyes ( p < 0.05 for all). No significant differences were detected between the fellow eyes and the control eyes in term of RNFLT values in any regions ( p > 0.05 for all).

Conclusion:

Lower RPCD values despite similar RNFLT values were observed in the fellow eyes of patients with unilateral BRVO compared with healthy controls. These results may indicate the shared vascular mechanisms and risk factors that account for the development of BRVO and glaucoma.

The Association among Blood Pressure, Blood Pressure Medications, and Glaucoma in a Nationwide Electronic Health Records Database

PURPOSE

To measure the association among blood pressure (BP), BP medications, and glaucoma using the All of Us Research Program database.

DESIGN

A retrospective, longitudinal cohort study leveraging a national electronic health record (EHR) database administered by the National Institutes of Health.

PARTICIPANTS

Eye patients in the All of Us Research Program database with at least 15 months of follow-up and 1 BP measurement.

METHODS

Univariable and multivariable Cox regression models predicted the risk of developing incident open-angle glaucoma (OAG). Mean arterial pressure (MAP) and the number of BP medication classes were entered as time-varying predictors to account for changes over time.

MAIN OUTCOME MEASURES

The risk of developing incident OAG, as defined by billing diagnosis codes.

RESULTS

Of 20 815 eligible eye patients who qualified for this study, 462 developed OAG. Low BP (MAP < 83.0 mmHg) was associated with increased risk of developing OAG (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.04-1.67). High BP (MAP > 101.3 mmHg) and the number of BP medication classes were not associated with OAG after adjustment for covariates. Other risk factors associated with OAG included being Black (HR, 3.31, 95% CI, 2.63-4.17), Hispanic or Latino (HR, 2.53, 95% CI, 1.94-3.28), Asian (HR, 2.22, 95% CI, 1.24-3.97), older in age (80+ years, HR, 20.1, 95% CI, 9.10-44.5), and diabetic (HR, 1.32, 95% CI, 1.04-1.67). Female gender was associated with decreased hazard of developing OAG (HR, 0.66, 95% CI, 0.55-0.80). No significant interaction was observed between MAP and the number of BP medications on the risk of developing OAG.

CONCLUSIONS

We found that low BP is associated with increased risk of developing OAG in a national longitudinal EHR database. We did not find evidence supporting a differential effect of medically treated and untreated low BP. This study adds to the body of literature implicating vascular dysregulation as a potential etiology for the development of OAG, particularly emphasizing the lack of influence of BP medications on this relationship.

Clinical Profiles of Glaucomatous Patients With High-tension and Low-tension Optic Disc Hemorrhages: A Comparative Study

PRCIS

Patients with low-tension optic disc hemorrhages (DHs) are more frequently women, have a diagnosis of normal-tension glaucoma (NTG) diagnosis and greater visual field (VF) loss. Symptoms of vascular dysregulation and Asian race also seem to be more prevalent in this clinical subtype.

PURPOSE

Optic DH is an important glaucoma risk factor, and occurs in a wide intraocular pressure (IOP) range. We sought to characterize distinct clinical subtypes of patients with high-tension disc hemorrhage (HTDH) and low-tension disc hemorrhage (LTDH).

PATIENTS AND METHODS

In this cross-sectional study, treated glaucomatous patients with DHs from 2 glaucoma services were consecutively enrolled. Disc photographs were evaluated for the presence of DH by 2 glaucoma specialists. After inclusion, patients were classified on HTDH (IOP≥16 mm Hg) and LTDH (IOP<16 mm Hg; median split). Clinical and ocular data from the time of DH detection were compared between groups.

RESULTS

One hundred thirty-three DH patients were included (LTDH=66 eyes; HTDH=67 eyes). Patients with LTDH were more often women than those with HTDH (77% vs. 42%; P=0.030). There was also a trend for a higher prevalence of Asian descendants (24% vs. 9%; P=0.058) and symptoms suggestive of vascular dysregulation (34% vs. 14%; P=0.057) in LTDH patients. Eyes with LTDH also had worse VF mean deviation index (P=0.037), higher prevalence of NTG diagnosis (46% vs. 17%; P<0.001), and tended to have thinner central corneas (P=0.066).

CONCLUSIONS

Patients developing DHs with treated IOPs in the low teens seem to more frequently fit in a profile represented by women, NTG diagnosis and greater VF loss. The presence of symptoms suggestive of vascular dysregulation and race also seem to differ between these 2 clinical subtypes. A closer optic disc surveillance is recommended for patients with the LTDH subtype, as they may develop DHs despite seemingly well-controlled IOP.

Normal-tension glaucoma: Current concepts and approaches-A review

Normal tension glaucoma (NTG) has remained a challenging disease. We review, from an epidemiological perspective, why we should redefine normality, act earlier at lower pre-treatment intraocular pressure (IOP) level, and the role of ocular perfusion pressures, noting that perfusion is affected by defective vascular bed autoregulation and endothelial dysfunction. The correlation of silent cerebral infarcts (SCI) and NTG may indicate that NTG belongs to a wider spectrum of small vessel diseases (SVD), with its main pathology being also on vascular endothelium. Epidemiological studies also suggested that vascular geometry, such as fractal dimension, may affect perfusion efficiency, occurrence of SCI, SVD and glaucoma. Artificial intelligence with deep learning, may help predicting NTG progression from vascular geometry. Finally, we review latest evidence on the role of minimally-invasive glaucoma surgery, lasers, and newer drugs. We conclude that IOP is not the only modifiable risk factors as, many vascular risk factors are readily modifiable.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Nutritional supplementation in the prevention and treatment of Glaucoma

Glaucoma is a chronic optic neuropathy that creates a significant burden on public health. Oxidative stress is hypothesised to play a role to glaucoma progression, and its reduction is being analysed as a therapeutic target. Dietary antioxidants play a crucial role in helping provide insight into this hypothesis. We reviewed 71 trials, interventional, I -vivo and I -vitro, including 11 randomised controlled trials, to determine if adjunctive nutritional supplementation could lead to a reduction in oxidative stress and prevent glaucomatous progression. Many laboratory findings show that vitamins and natural compounds contain an abundance of intrinsic antioxidative, neuroprotective and vasoprotective properties that show promise in the treatment and prevention of glaucoma. Although there is encouraging early evidence, most clincial findings are inconclusive. The group of B vitamins appear to have the greatest amount of evidence. Other compounds such as flavonoids, carotenoids, curcumin, saffron, CoQ10, Ggngko Biloba and Resveratrol however warrant further investigation in glaucoma patients. Studies of these antioxidants and other nutrients could create adjunctive or alternative preventative and treatment modalities for glaucoma to those currently available.

Comparison of optical coherence tomography angiography metrics in primary angle-closure glaucoma and normal-tension glaucoma

To investigate the peripapillary vascular metrics in early normal tension glaucoma (NTG) and early primary angle closure glaucoma (PACG) eyes using optical coherence tomography angiography (OCT-A). One or both eyes of each subject were imaged for a 3 × 3 mm peripapillary region by swept-source OCT-A (DRI-OCT Triton, Topcon, Japan) and assessed by an automated MATLAB program. OCT-A metrics including circumpapillary vessel density (cpVD) and fractal dimension (cpFD) were compared. Their association with visual field (VF) parameters and retinal nerve fiber layer (RNFL) thickness were determined. Sixty-eight eyes of 51 PACG, 68 eyes of 48 NTG, and 68 eyes of 49 control subjects were cross-sectionally analyzed. NTG eyes had significantly lower global cpVD (52.369 ± 0.781%) compared with PACG eyes (55.389 ± 0.721%, P = 0.004) that had comparable disease severity and average RNFL thickness. Multivariable analysis revealed that, for PACG and NTG eyes, decreased cpVD ([PACG] β = -4.242; CI: -8.120, -0.363 vs [NTG] β = -5.531; CI: -9.472, -1.590) and cpFD ([PACG] β = -8.894;CI: -11.925, -5.864 vs [NTG] β = -12.064; CI: -17.095, -6.932) were associated with decreased RNFL thickness (all P ≤ 0.032); with a stronger association between decrease cpFD and decreased RNFL thickness in NTG eyes (P = 0.028). Decreased cpVD was associated with decrease mean deviation (MD) in NTG eyes (β = -0.707; CI: -1.090, -0.324; P ≤ 0.001) and not associated with the visual field parameters in PACG eyes. Early NTG had lower global cpVD compared with early PACG, despite similar disease severity and average RNFL thickness.

Measurements of OCT Angiography Complement OCT for Diagnosing Early Primary Open-Angle Glaucoma

PURPOSE

To compare measurements of global and regional circumpapillary capillary density (cpCD) with retinal nerve fiber layer (RNFL) thickness and characterize their relationship with visual function in early primary open-angle glaucoma (POAG).

DESIGN

Cross-sectional study.

PARTICIPANTS

Eighty healthy eyes, 64 preperimetric eyes, and 184 mild POAG eyes from the Diagnostic Innovations in Glaucoma Study.

METHODS

Global and regional RNFL thickness and cpCD measurements were obtained using OCT and OCT angiography (OCTA). For direct comparison at the individual and diagnostic group level, RNFL thickness and capillary density values were converted to a normalized relative loss scale.

MAIN OUTCOME MEASURES

Retinal nerve fiber layer thickness and cpCD normalized loss at the individual level and diagnostic group. Global and regional areas under the receiver operating characteristic curve (AUROC) for RNFL thickness and cpCD to detect preperimetric glaucoma and glaucoma, R² for the strength of associations between RNFL thickness function and capillary density function in diagnostic groups.

RESULTS

Both global and regional RNFL thickness and cpCD decreased progressively with increasing glaucoma severity (P < 0.05, except for temporal RNFL thickness). Global and regional cpCD relative loss values were higher than those of RNFL thickness (P < 0.05) in preperimetric glaucoma (except for the superonasal region) and glaucoma (except for the inferonasal and superonasal regions) eyes. Race, intraocular pressure (IOP), and cpCD were associated with greater cpCD than RNFL thickness loss in early glaucoma at the individual level (P < 0.05). Global measurements of capillary density (whole image capillary density and cpCD) had higher diagnostic accuracies than RNFL thickness in detecting preperimetric glaucoma and glaucoma (P < 0.05; except for cpCD/RNFL thickness comparison in glaucoma [P = 0.059]). Visual function was significantly associated with RNFL thickness and cpCD globally and in all regions (P < 0.05, except for temporal RNFL thickness-function association [P = 0.070]).

CONCLUSIONS

Associations between capillary density and visual function were found in the regions known to be at highest risk for damage in preperimetric glaucoma eyes and all regions of mild glaucoma eyes. In early glaucoma, capillary density loss was more pronounced than RNFL thickness loss. Individual characteristics influence the relative magnitudes of capillary density loss compared with RNFL thickness loss. Retinal nerve fiber layer thickness and microvascular assessments are complementary and yield valuable information for the detection of early damages seen in POAG.

Analysis of the choroidal vascularity in asymmetric pseudoexfoliative glaucoma using optical coherence tomography-based image binarization

PURPOSE

To analyse choroidal vascular properties using an image binarization tool in patients with asymmetric pseudoexfoliative glaucoma (PXG) and compare them with healthy individuals.

METHODS

This cross-sectional study included 144 eyes of 96 patients. The eyes were divided into three groups: 48 glaucomatous eyes and 48 non-glaucomatous contralateral eyes with no clinically observable pseudoexfoliation material of patients with asymmetric PXG, and 48 control eyes. Enhanced depth imaging optical coherence tomography scans of the macula and 3.4-mm diameter, 360-degree circle scans of the optic nerve head were binarized using ImageJ software (National Institutes of Health, Bethesda, MD, USA). The choroidal vascularity index (CVI) was calculated as the ratio of the luminal area to the total circumscribed choroidal area.

RESULTS

The macular CVI (mCVI) was significantly lower in the glaucomatous eyes than in the fellow eyes (p = 0.007) and the control eyes (p = 0.001). The peripapillary CVI (pCVI) in all sectors was significantly lower in the glaucomatous eyes than in the other two groups (all p < 0.05). Non-glaucomatous fellow eyes had lower CVI values in the macula and in the peripapillary region, except for the superior-nasal and nasal sectors, compared to the control eyes (all p < 0.05). In multivariate regression analysis, while the cup-to-disc ratio was negatively associated with the pCVI, AL was negatively associated with the mCVI in both eyes of patients with PXG.

CONCLUSIONS

CVI was decreased in the macula and peripapillary area in glaucomatous eyes. Furthermore, the CVI tended to decrease in non-glaucomatous fellow eyes of PXG patients. This finding may suggest subclinical involvement and require further exploration into the pathogenesis of glaucoma.

Targeted Lipidomic Analysis of Aqueous Humor Reveals Signaling Lipid-Mediated Pathways in Primary Open-Angle Glaucoma

Simple Summary

Analysis of the eye liquids collected from a cohort of primary open-angle glaucoma patients identified signaling lipids, the pattern of which suggests a role of arachidonic acid/platelet activating-factor (PAF)-dependent pathways and oxidative stress in the pathogenesis of the disease and provides novel targets for its diagnostics and treatment.

Abstract

Primary open-angle glaucoma (POAG) is characterized by degeneration of retinal ganglion cells associated with an increase in intraocular pressure (IOP) due to hindered aqueous humor (AH) drainage through the trabecular meshwork and uveoscleral pathway. Polyunsaturated fatty acids and oxylipins are signaling lipids regulating neuroinflammation, neuronal survival and AH outflow. Among them, prostaglandins have been previously implicated in glaucoma and employed for its treatment. This study addressed the role of signaling lipids in glaucoma by determining their changes in AH accompanying IOP growth and progression of the disease. Eye liquids were collected from patients with POAG of different stages and cataract patients without glaucoma. Lipids were identified and quantified by UPLC-MS/MS. The compounds discriminating glaucoma groups were recognized using ANCOVA and PLS-DA statistic approaches and their biosynthetic pathways were predicted by bioinformatics. Among 22 signaling lipids identified in AH, stage/IOP-dependent alterations in glaucoma were provided by a small set of mediators, including 12,13-DiHOME, 9- and 13-HODE/KODE, arachidonic acid and lyso-PAF. These observations correlated with the expression of cytochromes P450 (CYPs) and phospholipases A2 in the ocular tissues. Interestingly, tear fluid exhibited similar lipidomic alterations in POAG. Overall, POAG may involve arachidonic acid/PAF-dependent pathways and oxidative stress as evidenced from an increase in its markers, KODEs and 12,13-DiHOME. The latter is a product of CYPs, one of which, CYP1B1, is known as POAG and primary congenital glaucoma-associated gene. These data provide novel targets for glaucoma treatment. Oxylipin content of tear fluid may have diagnostic value in POAG.

Longer Axial Length Potentiates Relationship of Intraocular Pressure and Peripapillary Vessel Density in Glaucoma Patients

Purpose

The purpose of this study was to investigate how axial length (AL) changes the relationship of intraocular pressure (IOP) with peripapillary vessel density (pVD) in glaucoma versus non-glaucomatous eyes.

Methods

A population-based, cross-sectional study of 2127 African Americans aged 40 years and older in Inglewood, California, were imaged with 6 × 6-mm optic disc optical coherence tomography angiography scans. There were 1028 healthy subjects (1539 eyes) and 65 subjects with glaucoma (86 eyes) who met inclusion criteria. A multivariable linear mixed effects regression model investigated the relationship of IOP on pVD after controlling for signal strength, retinal nerve fiber layer thickness, and age. These results were stratified by AL groups.

Results

Higher IOP was a significant predictor of lower pVD among subjects with glaucoma (P = 0.009), but not among healthy subjects (P = 0.26). After stratifying by the sample median AL (23.46 mm), higher IOP was associated with lower pVD among subjects with glaucoma with longer AL (≥ 23.46 mm, P = 0.005), but not among those in the shorter AL (< 23.46 mm, P = 0.45). IOP was not significantly associated with pVD among healthy subjects in either AL stratum.

Conclusions

Among subjects with glaucoma with longer AL, IOP was significantly associated with pVD. This relationship was not seen among subjects with glaucoma with shorter AL or non-glaucomatous subjects in either AL group. These findings support the hypothesis that disturbed retinal autoregulation may be present in subjects with glaucoma with longer AL. Longitudinal studies are needed to further investigate whether axial elongation increases glaucoma risk by compromising retinal autoregulation.

Proteome Characterization of Glaucoma Aqueous Humor

Glaucoma is the leading cause of irreversible blindness worldwide. The proteome characterization of glaucoma is not clearly understood. A total of 175 subjects, including 57 primary acute angle-closure glaucoma (PAACG), 50 primary chronic angle-closure glaucoma (PCACG), 35 neovascular glaucoma (NVG), and 33 cataract patients, were enrolled and comparison proteomic analysis was provided. The samples were randomly divided into discovery group or validation group, whose aqueous humor proteome was analyzed by data-independent acquisition or by parallel reaction monitoring. The common proteome features of three types of glaucoma were immune response, lipid metabolism, and cell death. Three proteins, VTN, SERPIND1, and CD14, showed significant upregulation in glaucoma and could discriminate glaucoma from cataract. Mutual differential proteomic analysis of PAACG, PCACG, and NVG showed different proteome characterization of the three types of glaucoma. NVG was characterized with activated angiogenesis. PAACG was characterized with activation of inflammation response. SERPIND1 was discovered to play vital role in glaucoma occurrences, which is associated with eye transparency decrease and glucose metabolism. This study would provide insights in understanding proteome characterization of glaucoma and benefit the clinical application of AH proteome.

•

Aqueous humor proteome of different glaucoma (PACG, NVG) was profiled.

•

Potential protein biomarkers for glaucoma were proposed.

•

Potential mechanism of glaucoma was described.

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SERPIND1 was discovered to have potential value for glaucoma diagnosis.

Agonistic autoantibodies against ß2-adrenergic receptor influence retinal microcirculation in glaucoma suspects and patients

PURPOSE

Agonistic β2-adrenergic receptor autoantibodies (β2-agAAb) have been observed in sera of patients with ocular hypertension and open-angle glaucoma (OAG). They target the β2-receptors on trabecular meshwork, ciliary body and pericytes (Junemann et al. 2018; Hohberger et al. 2019). In addition to their influence on the intraocular pressure, an association to retinal microcirculation is discussed. This study aimed to investigate foveal avascular zone (FAZ) characteristics by en face OCT angiography (OCT-A) in glaucoma suspects and its relationship to β2-agAAb status in patients with OAG.

MATERIAL AND METHODS

Thirty-four patients (28 OAG, 6 glaucoma suspects) underwent standardized, clinical examination including sensory testing as white-on-white perimetry (Octopus G1, mean defect, MD) and structural measures as retinal nerve fibre layer (RNFL) thickness, neuroretinal rim width (BMO-MRW), retinal ganglion cell layer (RGCL) thickness, and inner nuclear layer (INL) thickness with high-resolution OCT. FAZ characteristics were measured by OCT-A scans of superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). FAZ-R was calculated (area FAZ (SVP)/area FAZ (ICP)). Using cardiomyocyte bioassays we analysed serum samples for the presence of β2-agAAb.

RESULTS

(I) Total mean FAZ area [mm2]: 0.34±0.16 (SVP), 0.24±0.12 (ICP), and 0.49±0.24 (DCP); mean FAZ-R 1.58±0.94. No correlation was seen for FAZ-R with MD, RNFL, BMO-MRW, RGCL thickness and INL thickness (p>0.05). (II) ß2-agAAb have been observed in 91% patients and showed no correlation with MD, RNFL, BMO-MRW, RGCL thickness and INL thickness (p>0.05). (III) FAZ-R correlated significantly with the β2-agAAb-induced increase of the beat rate of cardiomyocyte (p = 0.028).

CONCLUSION

FAZ characteristics did not correlate with any glaucoma associated functional and morphometric follow-up parameter in the present cohort. However, level of β2-agAAb showed a significantly correlation with FAZ-ratio. We conclude that β2-agAAb might be a novel biomarker in glaucoma pathogenesis showing association to FAZ-ratio with OCT-A.

Agonistic β2-Adrenergic Receptor Autoantibodies Characterize the Aqueous Humor of Patients With Primary and Secondary Open-Angle Glaucoma

Purpose

Agonistic β2-adrenergic receptor autoantibodies (β2-agAAbs) were recently observed in sera of patients with ocular hypertension (OHT), primary (POAG), and secondary open-angle glaucoma (SOAG), yet not in healthy controls (HCs). It was the aim of the present study to investigate the presence of β2-agAAb in aqueous humor (AH) samples of OAG patients and to correlate these with the corresponding β2-agAAb serum data.

Material and Methods

Thirty-nine patients (21 male, 18 female) were recruited from the Department of Ophthalmology, University of Erlangen-Nürnberg: twenty-one POAG, 18 SOAG. Aqueous humor samples were collected during minimal invasive glaucoma surgery. Serum and AH samples were analyzed for β2-agAAb by a bioassay quantifying the beating rate of cultured cardiomyocyte (cut-off: 2 U).

Results

Thirty-six of 39 (92.3%) and 34 of 39 (87.2%) of OAG patients showed a β2-agAAb in their sera and AH samples, respectively. All β2-agAAb AH-positive OAG patients were also seropositive. We also observed a β2-agAAb seropositivity in 95 and 89% of patients with POAG and SOAG, respectively. Beta2-agAAbs were seen in 86% (POAG) and 78% (SOAG) of AH samples. The β2-agAAb adrenergic activity was increased in the AH of patients with POAG (6.5 ± 1.5 U) when compared with those with SOAG (4.1 ± 1.1 U; p = 0.004). Serum β2-agAAb adrenergic activity did not differ between the cohorts [POAG (4.5 ± 1.5 U); SOAG (4.6 ± 2.1 U; p=0.458)]. No correlation of the beating rates were observed between serum and AH samples for group and subgroup analyses.

Conclusion

The detection of β2-agAAb in systemic and local circulations supports the hypothesis of a direct functional impact of these agAAbs on ocular G-protein coupled receptors. The high prevalence of β2-agAAb in serum and AH samples of patients with POAG or SOAG suggests a common role of these AAbs in the etiopathogenesis of glaucoma, independent of open-angle glaucoma subtype.

Serum Selenium Levels in Glaucoma: a Pilot Study

BACKGROUND

Trace elements are assumed to be involved in glaucoma pathogenesis via changes in oxidative stress. Especially serum selenium (Se) has been linked to this neurodegenerative disease. Serum Se levels differ between countries due to nutrition and ethnicity. It was the aim of the present study to investigate serum Se levels in primary open-angle glaucoma (POAG) patients and controls in Germany and to consider potential age and gender effects.

MATERIAL AND METHODS

The Se concentration of 39 serum samples (22 patients with POAG, 17 controls) were analyzed by inductively coupled plasma-sector field mass spectrometry (ICP-sf-MS) in high resolution mode. Covariance and percentile regression were analyzed. Age and gender were defined as confounding factors and their different trends were investigated. Moreover, age was examined across different quantiles of Se levels.

RESULTS

Total serum least-squares means (LS-means) Se levels were 132.02 µg/L (controls) and 134.86 µg/L (POAG). Total serum Se levels did not differ between the study groups (p > 0.05). Significant age and gender effects of serum Se were observed. Quantile analysis showed that the 1st serum Se quantile decreased with increasing age in POAG patients in contrast to controls. The odds ratios of the 1st serum Se were 1.3 (with 2nd quantile) and 1.3 (with 3rd quantile), respectively.

CONCLUSION

The serum Se level of the German cohort was almost half of those of the published US cohort (glaucoma 209.11 ng/mL; control 194.45 ng/mL). Age and gender effects were observed; the serum Se level increased with age in women (controls and POAG), however, Se levels decreased with age in men (controls and POAG).

OCT-angiography: Regional reduced macula microcirculation in ocular hypertensive and pre-perimetric glaucoma patients

PURPOSE

OCT-angiography (OCT-A) offers a non-invasive method to visualize retinochoroidal microvasculature. As glaucoma disease affects retinal ganglion cells in the macula, macular microcirculation is of interest. The purpose of the study was to investigate regional macular vascular characteristics in patients with ocular hypertension (OHT), pre-perimetric primary open-angle glaucoma (pre-POAG) and controls by OCT-A in three microvascular layers.

MATERIAL AND METHODS

180 subjects were recruited from the Erlangen Glaucoma Registry, the Department of Ophthalmology, University of Erlangen and residents: 38 OHT, 20 pre-POAG, 122 controls. All subjects received an ophthalmological examination including measurements of retinal nerve fibre layer (RNFL), retinal ganglion cell layer (RGC), inner nuclear layer (INL), and Bruch's Membrane Opening-Minimum Rim Width (BMO-MRW). Macular vascular characteristics (vessel density, VD, foveal avascular zone, FAZ) were measured by OCT-A (Spectralis OCT II) in superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP).

RESULTS

With age correction of VD data, type 3 tests on fixed effects showed a significant interaction between diagnosis and sectorial VD in SVP (p = 0.0004), ICP (p = 0.0073), and DCP (p = 0.0003). Moreover, a significance in sectorial VD was observed within each layer (p<0.0001) and for the covariate age (p<0.0001). FAZ differed significantly between patients' groups only in ICP (p = 0.03), not in SVP and DCP. For VD the AUC values of SVP, ICP, and DCP were highest among diagnostic modalities (AUC: 0.88, 95%-CI: 0.75-1.0, p<0.001).

CONCLUSION

Regional reduced macula VD was observed in all three retinal vascular layers of eyes with OHT and pre-POAG compared to controls, indicating localized microvascular changes as early marker in glaucoma pathogenesis.

Glaucoma and neuroinflammation: An overview

Glaucoma is an optic neuropathy characterized by well-defined optic disc morphological changes (i.e., cup enlargement, neuroretinal border thinning, and notching, papillary vessel modifications) consequent to retinal ganglion cell loss, axonal degeneration, and lamina cribrosa remodeling. These modifications tend to be progressive and are the main cause of functional damage in glaucoma. Despite the latest findings about the pathophysiology of the disease, the exact trigger mechanisms and the mechanism of degeneration of retinal ganglion cells and their axons have not been completely elucidated. Neuroinflammation may play a role in both the development and the progression of the disease as a result of its effects on retinal environment and retinal ganglion cells. We summarize the latest findings about neuroinflammation in glaucoma and examine the connection between risk factors, neuroinflammation, and retinal ganglion cell degeneration.

[Rho kinase inhibitors as new local therapy option in primary open angle glaucoma]

BACKGROUND

In 2014 in Japan and 2017 in the USA, the Rho-kinase inhibitors were approved as a new antiglaucomatous substance group and will now be launched in Europe.

OBJECTIVE

On this occasion the current state of knowledge on Rho-kinase inhibitors is presented.

METHODS

In intensive search in PubMed the relevant experimental and clinical literature on the Rho-kinase inhibitors ripasudil and netarsudil and the combination of netarsudil and latanoprost were selected and compiled for this review.

RESULTS

The intraocular pressure lowering efficacy of ripasudil and netarsudil is in the range of the beta blocker timolol and the prostaglandin analogue latanoprost. In the fixed combination netarsudil/latanoprost the intraocular pressure reduction is greater than that of the single components and reaches a target pressure of below 15 mm Hg in 32%. Conjunctival hyperemia with 53-65% is the most common local side effect. Systemic side effects are very rare and so far there are no contraindications.

CONCLUSION

The Rho-kinase inhibitors are an interesting new introduction for glaucoma therapy, as each new pressure-lowering therapy represents an additional chance to reach the individually defined target pressure level in a glaucoma patient with local therapy; however, many of the pleiotropic effects associated with Rho-kinase inhibitors have so far only been found experimentally and will require clinical confirmation in the future.

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.

Neuroinflammation in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.

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.