Latest Developments in Normal-Pressure Glaucoma: Diagnosis, Epidemiology, Genetics, Etiology, Causes and Mechanisms to Management

Non-Invasive Monitoring of Intracranial Pressure Pulse Waves from Closed Eyelids in Patients with Normal-Tension Glaucoma

Background and Objectives: Normal-tension glaucoma (NTG) is a subtype of primary open-angle glaucoma characterized by progressive optic nerve damage despite intraocular pressure (IOP) remaining within the normal range. The underlying pathophysiology of NTG remains incompletely understood, and its diagnosis is often delayed due to the lack of a definitive screening tool. This study aimed to evaluate differences in intracranial pressure pulse wave amplitude recorded from closed eyelids between NTG patients and control subjects using a novel non-invasive monitoring technology. Materials and Methods: A cross-sectional observational study was conducted, enrolling NTG patients and age-matched controls. Intracranial pressure pulse wave signals were recorded from closed eyelids using the 'Archimedes' 02 device, which employs a highly sensitive digital pressure sensor and hydromechanical coupling for signal transmission. The amplitude of recorded intracranial pressure pulse waves was analyzed and compared between groups. Statistical analyses were performed using IBM SPSS Statistics 30.0, with significance set at p < 0.05. Results: A total of 140 participants were enrolled, including 68 NTG patients and 72 controls. After applying exclusion criteria, 63 NTG patients and 68 controls were included in the final analysis. The median intracranial pressure pulse wave amplitude was significantly higher in NTG patients (0.1326 a.u.) than in controls (0.0889 a.u.), with p = 0.01. Conclusions: These findings suggest that intracranial pressure pulse wave monitoring may serve as a potential biomarker for NTG. Further studies are needed to determine the diagnostic accuracy, sensitivity, and specificity of this technology for NTG detection.

Evaluation of nerve fiber layer and ganglion cell complex changes in patients with migraine using optical coherence tomography

Purpose

To analyze changes in peripapillary retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness in migraine patients with and without aura compared to healthy controls and to identify factors influencing the occurrence of these anomalies.

Methods

This is a cross-sectional case-control study including migraine patients and control subjects. All patients and controls underwent a complete ophthalmological examination, RNFL and GCC thickness measurements using a spectral domain-OCT device.The duration of migraine, the frequency and duration of migraine attacks, the migraine disability assessment (MIDAS) and migraine severity scale (MIGSEV) questionnaire scores were recorded.

Results

One hundred and twenty eyes from 60 patients (60 eyes in the migraine without aura (MWoA) group and 60 eyes in the migraine with aura (MWA) group) were included. Control group included 30 age and gender matched healthy participants (60 eyes). OCT revealed that RNFL and GCC thickness were significantly reduced in the migraine without aura (MWoA) and in the migraine with aura (MWA) groups compared to the control group and in the migraine with aura (MWA) group compared to the migraine without aura (MWoA) group. Prolonged disease duration was associated to decreased GCC thickness. RNFL and GCC thickness were correlated to disease severity, attack frequency and duration. In the multivariate study, duration of migraine and attack frequency were the main determinant factors of nasal GCC thickness. Disease severity was the main determinant of RNFL and GCC thickness, with the exception of the nasal sector.

Conclusion

Our study emphasize the significant impact of both types of migraine on retinal structures. OCT would serve as a valuable biomarker in migraine.

Application of Negative Pressure by the Ocular Pressure Adjusting Pump to Provide a Sustained Reduction in IOP

Purpose

To evaluate the sustainability of IOP reduction with continuous negative pressure application over an extended duration with use of the Ocular Pressure Adjusting Pump.

Methods

Prospective, controlled, open-label, randomized, single site, pilot study. Subjects with primary open-angle glaucoma (OAG) were enrolled. One eye of each subject was randomized to receive negative pressure application; the fellow eye served as a control. The study eye negative pressure setting was programmed for 60% of the baseline IOP. Subjects wore the Ocular Pressure Adjusting Pump for 8 consecutive hours and IOP measurements occurred at 2-hour intervals for a total of 5 IOP measurements (08:00, 10:00, 12:00, 14:00, 16:00).

Results

Nine subjects successfully enrolled and completed the study. The mean programmed negative pressure setting was -12.0 mmHg. At baseline, the mean IOP in the study eye was 21.4 ± 4.3 mmHg. The mean IOP reduction in the study eye at hours 0, 2, 4, 6, and 8 was 8.1 (37%), 6.4 (28%), 6.3 (29%), 7.3 (34%) and 6.7 (31%), respectively. All IOP measurements during negative pressure application were reduced from baseline. There were no serious adverse events.

Conclusion

The Ocular Pressure Adjusting Pump provides a sustained reduction in IOP while the device is worn with negative pressure applied with an IOP reduction exceeding 25% across 8 hours of continuous wear.

Polygenic Risk Scores Driving Clinical Change in Glaucoma

Glaucoma is a clinically heterogeneous disease and the world's leading cause of irreversible blindness. Therapeutic intervention can prevent blindness but relies on early diagnosis, and current clinical risk factors are limited in their ability to predict who will develop sight-threatening glaucoma. The high heritability of glaucoma makes it an ideal substrate for genetic risk prediction, with the bulk of risk being polygenic in nature. Here, we summarize the foundations of glaucoma genetic risk, the development of polygenic risk prediction instruments, and emerging opportunities for genetic risk stratification. Although challenges remain, genetic risk stratification will significantly improve glaucoma screening and management.

Beyond the optic nerve: Genetics, diagnosis, and promising therapies for glaucoma

Glaucoma stands as a leading global cause of blindness, affecting millions. It entails optic nerve damage and vision loss, categorized into open-angle and closed-angle glaucoma with subtypes like POAG, ACG, XFG, PCG, PDG, and developmental glaucoma. The pathophysiological and genetic factors behind glaucoma remain partially understood, with past studies linking intraocular pressure (IOP) levels to retinal ganglion cell death. Open-angle glaucoma involves elevated resistance to aqueous outflow via the trabecular meshwork, while angle-closure glaucoma typically sees drainage pathways obstructed by the iris. Genes have been identified for POAG, ACG, XFG, PCG, PDG, and developmental glaucoma, allowing for early-onset detection and the emergence of gene therapy as an effective treatment. Nevertheless, diagnostic and treatment options have their constraints, necessitating large-scale, well-designed studies to deepen our grasp of genetics' role in glaucoma's pathogenesis. This review delves into glaucoma's risk factors, pathophysiology, genetics, diagnosis, and available treatment options, including gene therapy. Additionally, it suggests alternative therapies like yoga and meditation as adjunct treatments for glaucoma prevention. Overall, this review advances our comprehension of the pathophysiology and genetic associations of glaucoma while highlighting the potential of gene therapy as a treatment avenue. Further research is imperative to fully elucidate the genetic mechanisms underpinning glaucoma and to devise effective treatments.

Rodent genetically modified models of glaucoma

Glaucoma, one of the leading causes of irreversible blindness worldwide, is a complex and heterogenous disease. While environmental factors are important, it is well-recognized that the disease has a strong heritable component. With the advent of large-cohort genome wide association studies, a myriad of genetic risk loci has been linked to different forms of glaucoma. Animal models have been an indispensable tool in characterizing these loci, especially if they lie within coding regions in the genome. Not only do these models connect genotype to phenotype, advancing our understanding of glaucoma pathogenesis in the process, they also have valuable utility as a platform for the pre-clinical testing of potential therapies. In this review, we will outline genetic models used for studying the major forms of glaucoma, including primary open angle glaucoma, normal tension glaucoma, primary angle closure glaucoma, pigmentary glaucoma, pseudoexfoliation glaucoma, and early onset glaucoma, including congenital and developmental glaucoma, and how studying these models have helped shed light on human glaucoma.

Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma

PURPOSE

To compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).

METHODS

Baseline age and severity-matched NTG and PACG eyes (75 eyes of 60 patients for each subtype) were observed longitudinally. All participants' RNFL thickness were measured by optical coherence tomography (OCT); pVD were measured by swept-source OCT-angiography (OCT-A) and quantified by a customised MATLAB program. The rate of pVD loss and RNFL thinning were estimated by linear mixed-effects models.

RESULTS

NTG eyes had significant pVD loss in all sectors (p≤0.05) while PACG eyes' pVD loss was borderline significant in the global region (p=0.05). Significant RNFL thinning was detected in the inferotemporal and superonasal regions of both groups, and the superotemporal region in the NTG group (all p≤0.02). NTG had faster rate of pVD loss in the global (difference (95% CI) -1.08 (-1.90 to -0.27) %/year), temporal (-1.57 (-2.91 to -0.23) %/year) and superotemporal (-1.46 (-2.65 to -0.26) %/year) regions than PACG (all p≤0.02), without significant difference of the rate of RNFL thinning. A lower baseline mean deviation (MD) was associated with a faster rate of global pVD loss, while a lower baseline pVD was associated with a slower rate of global pVD loss in multivariable analyses (both p≤0.04).

CONCLUSIONS

NTG had more extensive and faster rate of pVD loss than PACG. Baseline global pVD and MD were independently associated with the rate of pVD loss in NTG.

Role of epigenetic regulation in glaucoma

Glaucoma is the world's leading irreversible blinding eye disease. Lowering intraocular pressure is currently the only effective clinical treatment. However, there is a lack of long-acting IOP-lowering drugs, and some patients still experience retinal ganglion cell loss even with good intraocular pressure control. Currently, there is no effective method for neuroprotection and regeneration in clinical practice for glaucoma. In recent years, epigenetics has been widely researched and reported for its role in glaucoma's neuroprotection and regeneration. This article reviews the changes in histone modifications, DNA methylation, non-coding RNA, and m6A methylation in glaucoma, aiming to provide new perspectives for glaucoma management, protection of retinal ganglion cells, and axon regeneration by understanding epigenetic alterations.

Discrimination of glaucomatous from non-glaucomatous optic neuropathy with swept-source optical coherence tomography

OBJECTIVE

To assess the ability of optic nerve head (ONH) parameters, peripapillary retinal nerve fiber layer (pRNFL), and macular ganglion cell layer (GCL) thickness measurements with swept-source optical coherence tomography (SS-OCT), to discriminate between glaucomatous and non-glaucomatous optic neuropathy (GON and NGON).

METHODS

This retrospective cross-sectional study involved 189 eyes of 189 patients, 133 with GON and 56 with NGON. The NGON group included ischemic optic neuropathy, previous optic neuritis, and compressive, toxic-nutritional, and traumatic optic neuropathy. Bivariate analyses of SS-OCT pRNFL and GCL thickness and ONH parameters were performed. Multivariable logistic regression analysis was employed to obtain predictor variables from OCT values, and the area under the receiver operating characteristic curve (AUROC) was calculated to differentiate between NGON and GON.

RESULTS

Bivariate analyses showed that the overall and inferior quadrant of the pNRFL was thinner in the GON group (P=0.044 and P<0.01), while patients with NGON had thinner temporal quadrants (P=0.044). Significant differences between the GON and NGON groups were identified in almost all the ONH topographic parameters. Patients with NGON had thinner superior GCL (P=0.015), but there were no significant differences in GCL overall and inferior thickness. Multivariate logistic regression analysis demonstrated that vertical cup-to-disc ratio (CDR), cup volume, and superior GCL provided independent predictive value for differentiating GON from NGON. The predictive model of these variables along with disc area and age achieved an AUROC=0.944 (95% CI 0.898-0.991).

CONCLUSIONS

SS-OCT is useful in discriminating GON from NGON. Vertical CDR, cup volume, and superior GCL thickness show the highest predictive value.

Familial normal tension glaucoma genetics

Glaucoma is defined by characteristic optic nerve damage and corresponding visual field defects and is the leading cause of irreversible blindness in the world. Elevated intraocular pressure (IOP) is a strong risk factor for developing glaucoma. However, glaucoma can occur at any IOP. Normal tension glaucoma (NTG) arises with IOPs that are within what has been defined as a normal range, i.e., 21 mm Hg or less, which may present challenges in its diagnosis and management. Identifying inheritance patterns and genetic mutations in families with NTG has helped elucidate mechanisms of NTG, however the pathophysiology is complex and not fully understood. Approximately 2% of NTG cases are caused primarily by mutations in single genes, optineurin (OPTN), TANK binding kinase 1 (TKB1), or myocilin (MYOC). Herein, we review pedigree studies of NTG and autosomal dominant NTG caused by OPTN, TBK1, and MYOC mutations. We review identified mutations and resulting clinical features of OPTN-associated and TBK1-associated NTG, including long-term follow up of these patients with NTG. In addition, we report a new four-generation pedigree of NTG caused by a Glu50Lys OPTN mutation, including six family members with a mean follow up of 17 years. Common features of OPTN -associated NTG due to Glu50Lys mutation included early onset of disease with an IOP <21 mm Hg, marked optic disc cupping, and progressive visual field loss which appeared to stabilize once an IOP of less than 10 mm Hg was achieved. Lastly, we review risk factor genes which have been identified to contribute to the complex inheritance of NTG.

Metabolic syndrome as an independent risk factor for glaucoma: a nationally representative study

BACKGROUND

Central insulin resistance contributes to glaucoma development. Given the close association between metabolic syndrome MetS and insulin resistance, this study aimed to determine whether MetS is associated with glaucoma risk.

METHODS

We analyzed data from 11,499 adults aged ≥ 19 years in the 2019-2021 Korean National Health and Nutrition Examination Survey and applied sampling weights to represent the general Korean population. Participants were classified into groups with or without MetS. Ocular hypertension (HTN) was defined as intraocular pressure > 21 mmHg. Primary open-angle glaucoma (POAG) was diagnosed based on the results of a visual field test and optical coherence tomography using the criteria published by the International Society for Geographic and Epidemiological Ophthalmology. We further divided POAG into normal tension (NTG) and POAG with ocular HTN. A spline curve was drawn to determine the dose-response relationship between the number of MetS components and risk of POAG. Odds ratios (ORs) with 95% confidence interval (CI) for POAG according to MetS status were estimated using weighted logistic regression analyses.

RESULTS

The prevalence of POAG was 5.7% and 3.5%, respectively, in groups with and without MetS. We identified a dose-response relationship between the number of MetS components and risk of POAG. Unadjusted ORs (95% CI) for POAG in the group with MetS was 1.85 (1.52-2.25), compared with those without MetS. The trends persisted in adjusted models. The fully-adjusted OR (95% CI) for POAG was 1.47 (1.04-2.09) in the group with MetS. Subgroup analysis revealed that a significant relationship remained only in the NTG group (fully adjusted OR, 1.50; 95% CI 1.05-2.15).

CONCLUSIONS

A comprehensive ophthalmological assessment should be considered for persons with MetS who are at increased risk of POAG, particularly NTG.

Reference values for trans-laminar cribrosa pressure difference and its association with systemic biometric factors

OBJECTIVES

To provide reference values of trans-laminar cribrosa pressure difference (TLCPD) and reveal the association of TLCPD with systemic biometric factors.

METHODS

In this cross-sectional study, 526 quasi-healthy subjects (including 776 eyes) who required lumbar puncture for medical reasons were selected from 4915 neurology inpatients from 2019 to 2022. Patients with any diseases affecting intraocular pressure (IOP) or intracranial pressure (ICP) were excluded. The ICPs of all subjects were obtained by lumbar puncture in the left lateral decubitus position. IOP was measured in the seated position by a handheld iCare tonometer prior to lumbar puncture. TLCPD was calculated by subtracting ICP from IOP. Systemic biometric factors were assessed within 1 h prior to TLCPD measurement.

RESULTS

The TLCPD (mean ± standard deviation) was 4.4 ± 3.6 mmHg, and the 95% reference interval (defined as the 2.5th-97.5th percentiles) of TLCPD was -2.27 to 11.94 mmHg. The 95% reference intervals for IOP and ICP were 10-21 and 6.25-15.44 mmHg, respectively. IOP was correlated with ICP (r = 0.126, p < 0.001). TLCPD was significantly negatively correlated with body mass index (r = -0.086, p = 0.049), whereas it was not associated with age, gender, height, weight, blood pressure, pulse, or waist and hip circumference.

CONCLUSIONS

This study provides reference values of TLCPD and establishes clinically applicable reference intervals for normal TLCPD. Based on association analysis, TLCPD is higher in people with lower BMI.

Mendelian Randomization Implicates Bidirectional Association between Myopia and Primary Open-Angle Glaucoma or Intraocular Pressure

PURPOSE

Observational studies suggest that myopic eyes carry a greater risk of primary open-angle glaucoma (POAG); however, the evidence for this association is inconsistent. This may be the result of confounding factors that arise from myopia that complicate clinical tests for glaucoma. This study used Mendelian randomization (MR) analysis to determine genetic causal associations among myopia, glaucoma, and glaucoma-related traits that overcome the effects of external confounders.

DESIGN

Bidirectional genetic associations between myopia and refractive spherical equivalent (RSE), POAG, and POAG endophenotypes were investigated.

PARTICIPANTS

Data from the largest publicly available genetic banks (n = 216,257-542,934) were analyzed.

METHODS

Multiple MR models and multivariate genomic structural modeling to identify significant mediators for the relationship between myopia and POAG.

MAIN OUTCOME MEASURES

Genetic causal associations between myopia and POAG and POAG endophenotypes.

RESULTS

We found consistent bidirectional genetic associations between myopia and POAG and between myopia and intraocular pressure (IOP) using multiple MR models at Bonferroni-corrected levels of significance. Intraocular pressure showed the most significant mediation effect on RSE and POAG (Sobel test, 0.13; 95% confidence interval, 0.09-0.17; P = 1.37 × 10^-8).

CONCLUSIONS

A strong bidirectional genetic causal link exists between myopia and POAG that is mediated mainly by IOP. Our findings suggest that IOP-lowering treatment for glaucoma may be beneficial in myopic eyes, despite the challenges of establishing a clear clinical diagnosis.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Self-reported glaucoma prevalence and related factors, contribution to reported visual impairment, and functional burden in a cross-sectional study in Colombia

PURPOSE

Describe the self-reported prevalence of glaucoma in Colombian older adults, emphasizing the most important risk factors and associated daily-life functional alterations.

METHODS

This a secondary analysis of the Health, Wellness, and Aging survey conducted in the year 2015. Diagnosis of glaucoma was obtained from self-report. Functional variables were assessed through activities of daily living questionnaires. A descriptive analysis followed by bivariate and multivariate regression models adjusting for confounding variables was conducted.

RESULTS

Self-reported prevalence of glaucoma was 5.67%, with higher rate in women, OR 1.22 (1.13-1.40) p = .003, older age OR 1.02 (1.01-1.02) p < .001, and with higher education OR 1.38 (1.28-1.50) p < .001. Glaucoma was independently associated with diabetes OR 1.37 (1.18-1.61) p  < .001 and hypertension 1.26 (1.08-1.46) p = .003. It also showed statistically significant correlations with poor SRH OR 1.15 (1.02-1.32) p < .001, self-reported visual impairment 1.73 (1.50-2.01) p < .001, and impairment in money management OR 1.59 (1.16-2.08) p  = .002, grocery shopping OR 1.57 (1.26-1.96) p < .001 and preparing meals OR 1.31 (1.06-1.63) p  = .013 and having had falls during the last year OR 1.14 (1.01-1.31) p = 0.041.

CONCLUSION

Our findings suggest the self-reported prevalence of glaucoma in older adults in Colombia to be higher than reported data. Glaucoma and visual impairment in older adults represent a public health concern, since glaucoma was associated with adverse outcomes like functional loss and risk of falling, affecting the quality of life and their participation in society.

Risk of Normal Tension Glaucoma Progression From Automated Baseline Retinal-Vessel Caliber Analysis: A Prospective Cohort Study

PURPOSE

To determine the relationship between baseline retinal-vessel calibers computed by a deep-learning system and the risk of normal tension glaucoma (NTG) progression.

DESIGN

Prospective cohort study.

METHODS

Three hundred and ninety eyes from 197 patients with NTG were followed up for at least 24 months. Retinal-vessel calibers (central retinal arteriolar equivalent [CRAE] and central retinal venular equivalent [CRVE]) were computed from fundus photographs at baseline using a previously validated deep-learning system. Retinal nerve fiber layer (RNFL) thickness and visual field (VF) were evaluated semiannually. The Cox proportional-hazards model was used to evaluate the relationship of baseline retinal-vessel calibers to the risk of glaucoma progression.

RESULTS

Over a mean follow-up period of 34.36 ± 5.88 months, 69 NTG eyes (17.69%) developed progressive RNFL thinning and 22 eyes (5.64%) developed VF deterioration. In the multivariable Cox regression analysis adjusting for age, gender, intraocular pressure, mean ocular perfusion pressure, systolic blood pressure, axial length, standard automated perimetry mean deviation, and RNFL thickness, narrower baseline CRAE (hazard ratio per SD decrease [95% confidence interval], 1.36 [1.01-1.82]) and CRVE (1.35 [1.01-1.80]) were associated with progressive RNFL thinning and narrower baseline CRAE (1.98 [1.17-3.35]) was associated with VF deterioration.

CONCLUSION

In this study, each SD decrease in the baseline CRAE or CRVE was associated with a more than 30% increase in the risk of progressive RNFL thinning and a more than 90% increase in the risk of VF deterioration during the follow-up period. Baseline attenuation of retinal vasculature in NTG eyes was associated with subsequent glaucoma progression. High-throughput deep-learning-based retinal vasculature analysis demonstrated its clinical utility for NTG risk assessment.

Increased Risk of Ocular Hypertension in Patients With Cushing's Disease

PRCIS

An increased risk of ocular hypertension was seen in Cushing's disease.

INTRODUCTION

Systemic steroid use is a significant risk factor for increased intraocular pressure (IOP). The incidence of ocular hypertension may rise to 30%-40% of the general population due to topical or systemic glucocorticoid usage. However, the incidence of ocular hypertension in endogenous hypercortisolemia, as well as the ophthalmological outcomes after endocrine remission due to surgical resection, remain unknown.

MATERIALS AND METHODS

The IOP, visual field, and peripapillary retinal nerve fiber layer thickness were documented in all patients with Cushing's disease (CD) admitted to a tertiary pituitary center for surgery from January to July 2019. Patients with acromegaly and patients with nonfunctioning pituitary adenoma (NFPA) during the same study period served as controls. We calculated the odds ratio (OR), identified the risk factors of developing ocular hypertension, and presented postoperative trends of the IOP.

RESULTS

A total of 52 patients (38.4±12.4 y old) with CD were included. The IOP was higher in patients with CD (left 19.4±5.4 mm Hg and right 20.0±7.1 mm Hg) than in patients with acromegaly (left 17.5±2.3 mm Hg and right 18.6±7.0 mm Hg, P =0.033) and patients with NFPA (left 17.8±2.6 mm Hg and right 17.4±2.4 mm Hg, P =0.005). A total of 21 eyes (20.2%) in patients with CD were diagnosed with ocular hypertension compared with 4 eyes (4.7%) in the acromegaly group and 4 eyes (4.5%) in the NFPA group. The OR of developing ocular hypertension in patients with CD was 5.1 [95% confidence interval (CI), 1.3-25.1, P =0.029] and 6.6 (95% CI, 1.8-30.3, P =0.007) when compared with the 2 control groups. Among patients with CD, those with a higher urine-free cortisol were more likely to develop ocular hypertension (OR=19.4, 95% CI, 1.7-72.6). The IOP decreased at 1 month after surgery in patients with CD, and the change was sustained for 3 months after surgery.

CONCLUSIONS

An increased risk of ocular hypertension was seen in CD and suggests that endogenous hypercortisolemia should be considered as part of the glaucoma assessment. This result warrants the discretion of both ophthalmologists and neuroendocrinologists.

Association Between HSPA5 Promoter Polymorphisms and a Reduced Risk of Normal Tension Glaucoma

INTRODUCTION

In Normal Tension Glaucoma (NTG), factors other than elevated Intraocular Pressure (IOP) are likely to play a role in the pathogenesis of optic neuropathy. The potential similarities between Alzheimer's disease and NTG in cellular apoptosis leading to neuro-degeneration have been shown in recent studies. HSPA5 (Heat Shock Protein family A member 5) promoter polymorphisms have been reported to be associated with a risk of Alzheimer's Disease (AD). The purpose of our study was to investigate the role of HSPA5 promoter polymorphisms in NTG patients.

METHODS

A total of 222 patients with NTG, along with 236 normal controls were enrolled in this study. Genomic DNA was amplified through a Polymerase Chain Reaction (PCR) and identified for the polymorphic HSPA5 (-415 and -370) by Xmn1 and BstY1 restriction digestion, respectively. PCR fragments with potential polymorphic HSPA5 (-180) were subjected to sequence-analyses by a Hex-labeled primer. Genotypes for both the NTG patients and control groups were compared for statistically significant differences.

RESULTS

Polymorphisms (-415) G/A and (-180) del/G were completely linked in our population. The genotype and allele frequency distribution at the -415 G/A and -180 del/G sites showed a significant difference between the NTG cases and controls. The genotype frequency of HSPA5 (-415) AA / (-180) GG and the allele frequency of HSPA5 (-415) A / (-180) G were significantly lower (p=0.04 and p= 0.01, respectively) in the NTG patients when compared with those in the control group. There was no significant difference in genotype or allele frequency distribution of the HSPA5 (-370) C/T between the NTG and control groups. There was a reduced risk of NTG associated with the carriers for the HSPA5 (-415) A / (-180 ) G allele compared with that in the control population (p=0.01).

CONCLUSION

HSPA5 (-415) A and (-180) G allele polymorphisms may be protective factors in the development of NTG.

MicroPulse Transscleral Laser Therapy Demonstrates Similar Efficacy with a Superior and More Favorable Safety Profile Compared to Continuous-Wave Transscleral Cyclophotocoagulation

Purpose. The aim of this study was to compare effectiveness and safety of MicroPulse transscleral laser therapy (MP-TLT) using the original MicroPulse P3® device and continuous-wave transscleral cyclophotocoagulation (CW-TSCPC) using the G-Probe® device in glaucoma. Methods. Spherical equivalent, intraocular pressure (IOP), best-corrected visual acuity (BCVA), and number of topical or oral ophthalmic pressure-reducing medications were registered at every time point, up to the last follow-up at 12 months. A complete slit-lamp examination was conducted to record the following complications: corneal edema, persistent ocular hypotony (IOP ≤5 mmHg) on two consecutive follow-up visits, choroidal detachment, phthisis bulbi, sympathetic ophthalmia, cystoid macular edema, or other abnormal ocular findings. Success was defined as IOP between 6 and 21 mmHg and >20% reduction in IOP with or without antiglaucoma medications. Results. 47 eyes underwent MP-TLT and 150 CW-TSCPC. At 12 months, success was achieved in 88.6% in the CW-TSCPC group and 87.5% in the MP-TLT group ( $p$  = 0.883). In the CW-TSCPC group, eyes achieved a 42.4% IOP reduction (from 28.3 ± 12.3 mmHg to 15.3 ± 6.0 mmHg) and a 31.1% reduction (from 22.0 ± 7.2 mmHg to 15.7 ± 4.8 mmHg) in the MP-TLT group. Visual acuity remained primarily unaltered in both groups. Conclusion. MP-TLT was as effective in lowering IOP as CW-TSCPC and achieved comparable success. Additionally, MP-TLT demonstrated consistent and effective outcomes at every time point. The improved safety profile of MP-TLT allows the therapeutic spectrum to be broadened, granting ophthalmologists’ treatment of glaucoma in earlier stages of glaucoma than those typically treated with CW-TSCPC, i.e., early to moderate and to patients with good central-vision.

First and second transscleral cyclophotocoagulation treatments provide similar intraocular pressure-lowering efficacy in patients with refractory glaucoma

Purpose

The aim of this study is to address the safety and effectiveness of a second continuous-wave transscleral cyclophotocoagulation (CW-TSCPC) treatment by comparing its outcome against a first CW-TSCPC treatment in the same patients with refractory glaucoma.

Methods

Twenty-one eyes with either primary or secondary glaucoma received a second CW-TSCPC laser session ≥ 3 months after the first treatment. Intraocular pressure (IOP), best-corrected visual acuity (BCVA), and number of topical or oral ophthalmic pressure-reducing medications were registered at every time point up to the last follow-up at 3 months. A complete slit-lamp examination was conducted to record for complications or other abnormal ocular findings. Success was defined as IOP between 6 and 21 mmHg and > 20% reduction in IOP with or without anti-glaucoma medications.

Results

At 3 months follow-up of the first CW-TSCPC treatment, a 24.8% decrease in IOP was observed, whereas a 45.6% IOP decrease was observed 3 months post the second CW-TSCPC treatment. Visual acuity did not decrease, and no major complications were observed post either treatment within the follow-up period. Time to failure was 79.5 ± 24.6 and 77.1 ± 29.4, respectively (P = 0.955). No serious complications were observed.

Conclusion

A second CW-TSCPC treatment proved to be a safe and effective treatment option when the first CW-TSCPC treatment was insufficient in maintaining the desired IOP level for a prolonged time (mean time between both sessions 6.4 ± 8.0 months).

Clinical Audit on the Effectiveness of Clinic-Based Intraocular Pressure Phasing for Patients With Glaucoma and Glaucoma Suspect

INTRODUCTION

Glaucoma is a complex disease with intraocular pressure (IOP) playing an important role in its diagnosis and management. IOP has shown diurnal and nocturnal variations, which may affect the course of the disease.

OBJECTIVE

The objective of this study was to determine the effectiveness of clinic-based office hour phasing in the diagnosis and management of glaucoma and glaucoma suspect (GS).

METHODS

A retrospective clinical audit was conducted on patients who were subjected to office hour phasing in a glaucoma clinic, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, between January 2015 and December 2019. The office hour phasing was conducted for various indications such as confirmation of diagnosis, screening, and effectiveness of treatment. IOP was recorded every two hours between 0800 and 1600 using an air puff tonometer by a trained nurse. Measurement of IOP was repeated with Goldmann applanation tonometer at sitting position by a trainee when the IOP ≥ 20 mmHg or discrepancy of IOP > 2 mmHg between two eyes. Other investigations including a Humphrey visual field and gonioscopy were conducted in between the IOP measurements. Diagnosis and clinical decisions on management were made at the end of the office hour clinic phasing.

RESULTS

A total of 83 patients (163 eyes) were included in this clinical audit. Their mean age was 59.3 (16.5) years with 59% of male patients. Both eyes showed an almost similar pattern of mean IOP over five daytime readings in the clinic. A total of 35 eyes (21.5%) showed fluctuation ≥ 6 mmHg, and 128 eyes (78.5%) showed stable IOP during the clinic hour phasing. There was a significant difference in the mean IOP pattern between groups with stable and fluctuating IOP based on repetitive measure analysis of variance (RM ANOVA) (p = 0.008). The final diagnosis was made for 39 eyes (21 OD [right eye] and 18 OS [left eye]) out of 131 eyes (29.8%) with GS. Confirmation of diagnosis was achieved in all eyes (100%) with suspected ocular hypertension (OHT) and normal-tension glaucoma (NTG). Progression of glaucoma was confirmed in four eyes (2 OD and 2 OS) out of 17 eyes (23.5%) with suspected progression.

CONCLUSION

Clinic hour IOP phasing provides a practical approach in confirmation of diagnosis and adjustment in the management of patients with glaucoma and GS.

Association of SIX1-SIX6 polymorphisms with peripapillary retinal nerve fibre layer thickness in children

PURPOSE

Association of SIX1-SIX6 variants with peripapillary retinal nerve fibre layer (p-RNFL) thickness had been reported in adults. This study aimed to investigate these associations in children, with further explorations by spatial, age and sex stratifications.

METHODS

2878 school children aged between 6 and 9 years were enrolled from the Hong Kong Children Eye Study. Three single-nucleotide polymorphisms (SNPs) at the SIX1-SIX6 locus were genotyped. The association of each SNP with p-RNFL thickness (including global and sectoral thickness) were evaluated using multiple linear regression.

RESULTS

SNPs rs33912345 (p=7.7×10^-4) and rs10483727 (p=0.0013) showed significant associations with temporal-inferior p-RNFL thickness. The C allele of rs33912345 was associated with a thinner temporal-inferior p-RNFL by an average of 2.44 µm, while rs10483727-T was associated with a thinner temporal-inferior p-RNFL by 2.32 µm. The association with temporal-inferior p-RNFL was the strongest in the 8-9 year-old group for rs33912345 (p=5.2×10^-4) and rs10483727 (p=3.3×10^-4). Both SNPs were significantly associated with temporal-inferior p-RNFL thickness in boys (p<0.0017), but not in girls (p>0.05). In contrast, rs12436579-C (β=1.66; p=0.0059), but not rs33912345-C (β=1.31; p=0.052) or rs10483727-T (β=1.19; p=0.078), was nominally associated with a thicker nasal-inferior p-RNFL.

CONCLUSIONS

Both rs33912345 and rs10483727 at SIX1-SIX6 were associated with p-RNFL thickness in children, especially at the temporal-inferior sector, with age-dependent and sex-specific effects. SNP rs12436579 was associated with nasal-inferior p-RNFL thickness. Our findings suggested a role of SIX1-SIX6 in RNFL variation during neural retina development in childhood.

12-Month Outcomes of Combined Phacoemulsification and iStent Inject in Asian Eyes with Normal Tension Glaucoma: A Single-Centre Experience

PURPOSE

To evaluate efficacy and safety of the iStent inject combined with phacoemulsification in Asian eyes with normal-tension glaucoma (NTG) up to 12 months after surgery.

STUDY DESIGN

Retrospective case series.

METHODS

Retrospective case series of eyes undergoing surgery from April 2017 to August 2019. Outcome measures included intraocular pressure (IOP), number of topical glaucoma medications and adverse outcomes. Data were retrieved from the post-operative day 1 (POD1), week 1 (POW1), month 1 (POM1), month 3 (POM3), month 6 (POM6) and month 12 (POM12) timepoints. Data were analysed at each timepoint for eyes with available clinical data at that visit. Subgroup analysis was performed for a consistent cohort which included only eyes with data at all six follow-up timepoints.

RESULTS

Data from 91 eyes in the collective subject group was analysed. Majority of subjects were male (53, 58.2%) and Chinese (79, 86.8%). Mean age was 73.2 ± 7.2 years. Pre-operatively, mean IOP was 14.3 ± 3.0 mmHg and mean number of medications was 1.5 ± 0.8. Significant IOP reduction was observed at all timepoints except POW1 and POM12. The number of medications was reduced at all timepoints (p < 0.001). By POM12, there was reduction of 1.2 ± 1.0 medications (p < 0.001). Both the collective and consistent cohorts demonstrated a trend towards decreasing surgical efficacy with time, in IOP reduction and decrease in medications. None of the eyes experienced sight-threatening complications.

CONCLUSIONS

Asian eyes with NTG undergoing combined phacoemulsification and iStent inject surgery demonstrated significant and sustained reduction in number of glaucoma medications up to 12 months post-operatively.

Laser in Glaucoma and Ocular Hypertension Trial (LIGHT) in China - A Randomized Controlled Trial: Design and Baseline Characteristics

PURPOSE

To describe the baseline characteristics of a trial to evaluate whether selective laser trabeculoplasty (SLT), as a first-line treatment, provides superior economic and health-related quality of life outcomes to medical treatment in China.

DESIGN

The LiGHT China trial is an unmasked, single-center, pragmatic, randomized controlled trial.

METHODS

A total of 771 previously undiagnosed patients with primary open angle glaucoma (POAG, 622 patients) or ocular hypertension (OHT, 149 patients) at Zhongshan Ophthalmic Center were recruited from March 2015 to January 2019. Subjects were randomized to SLT-1st (followed by medication then surgery when required) or Medicine-1st (medication followed by surgery when required). The primary outcome was health-related quality of life (HRQL). The secondary outcomes were clinical outcomes, cost, cost-effectiveness, Glaucoma Utility Index, Glaucoma Symptom Scale, visual function, and safety.

RESULTS

The mean age of POAG patients was 49.8 years and 38.8 years for OHT. The median intraocular pressure was 20 mm Hg for the 1,105 POAG eyes and 24 mm Hg for the 271 OHT eyes. POAG eyes had thinner central cornea thickness (CCT, 536 µm) than OHT eyes (545 µm). Median mean deviation of the visual field in POAG eyes was -4.2 dB. Median refractive error was -1.5 D for OHT eyes and -1.25 D for POAG eyes. There was no difference between POAG and OHT patients on baseline scores of GUI, GSS and VF-14. The difference between OHT and POAG on the EQ-5D-5L was 0.024.

CONCLUSIONS

Compared with participants in the LiGHT UK trial, participants in this trial were younger, more myopic and had more severe visual field defects.

Aspects of Tertiary Prevention in Patients with Primary Open Angle Glaucoma

The purpose of the study is to assess the health of patients in the activity of tertiary prevention dedicated to preventing blindness caused by POAG (primary glaucoma with open angle and high tension) and NTG (primary glaucoma with open-angle and statistically normal tension-particular form of glaucoma with open angle) and preservation of the remaining visual function. The design of the study is epidemiological, observational, descriptive and retrospective, and uses only the data recorded in the existing records in the archives of the Ophthalmology office within the Integrated Outpatient Clinic of the Emergency Clinical Hospital of Oradea (IOCECHO) during the years 1999-2019 (anamnestic data; objective examination and paraclinical examination: intraocular pressure-IOP and visual field-VF). The methods of the study included the standardized protocol: anamnesis, physical ophthalmological examination, IOP determination, and computerized perimetry with the "Fast Threshold" strategy performed with the "Opto AP-300" perimeter. The obtained results were statistically processed with a specialized software (S.P.S.S.-I.B.M. Statistics version 22). The study examined the available data of 522 patients of which 140 were men (26.8%) and 382 were women (73.2%). The gender ratio was 0.37. In the period 1999-2019, 150,844 people with ophthalmic pathology were consulted in the Ophthalmology office of IOCECHO out of which 522 patients (0.35%) were diagnosed with primitive open-angle glaucoma, 184 people (35.2%) presented high IOP (POAG), and 338 people (64.8%) had statistically normal IOP (NTG). The annual proportion of cases diagnosed with glaucoma in the total number of patients examined was between 0.1% (2005; 2008; 2010) and 2.4% in 2012, when 101 people were detected. In the studied records, no cases of uni- and/or bilateral blindness were mentioned. The mean age of glaucoma patients at the first consultation was 60.81 ± 12.14 years with high frequencies in the 55-69 age groups and at the last consultation it was 66.10 ± 12.47 years with high frequencies in the age groups between 60-74 years. Monitoring and treatment of glaucoma patients was beneficial; IOP decreased statistically significantly: in patients with POAG by 46.16%, from 30.50 ± 7.98 mmHg to 16.42 ± 3.01 mmHg (p = 0.000) and in those with NTG by 17.44%, at 16.39 ± 3.66 mmHg at 13.53 ± 1.92 mmHG (p = 0.000). The duration of treatment and monitoring was on average 5.1 ± 3.4 years, for 184 patients (35.2%) with POAG and 5.1 ± 3.8 years for 338 patients (64.8%) with NTG. Tertiary prevention of glaucoma, by providing specialized care, ensures effective control of IOP and implicitly of the long-term evolution of the disease. IOP is the only modifiable risk factor in patients with POAG and NTG and its decrease prevents the progression of the disease and emphasizes the importance of early diagnosis and treatment. The management of the glaucoma patient consisted of: complete ophthalmological examination (subjective and objective), paraclinical examination with IOP, and VF measurement (valuable ophthalmological diagnostic tool) for disease detection and effective assessment of disease progression in order to improve the process of therapeutic decision making.

Aerobic exercise reduces intraocular pressure and expands Schlemm's canal dimensions in healthy and primary open-angle glaucoma eyes

Purpose

Aerobic exercise (AE) has been reported to decrease intraocular pressure (IOP) in healthy subjects and there are concomitant morphological changes in the anterior segment of the eye including the Schlemm's canal (SC). However, its effects on IOP and SC morphology in glaucoma patients had not been studied before. We aim to investigate the effect of AE on the IOP and SC dimension in both healthy and primary open-angle glaucoma (POAG) eyes.

Methods

The area and diameter of SC and IOP were measured in 35 primary open-angle glaucoma (POAG) patients (59 eyes) and 36 healthy subjects (72 eyes) before and after performing moderate intensity of AE by running on a treadmill for 30 min. SC was imaged by swept-source optical coherence tomography (SS-OCT) for evaluation.

Results

In comparison with baseline values, mean IOP decreased significantly following AE in both POAG and healthy eyes (both P < 0.001), in which POAG eyes showed a greater degree of reduction compared to healthy eyes (P = 0.002). In comparison with baseline values, in both POAG and healthy eyes, the average cross-sectional area (POAG: 80.48 +/- 59.54 vs. 99.20 +/- 54.87 pixels; healthy: 151.84 +/- 52.76 vs. 198.23 +/- 53.70 pixels; both P < 0.001) and diameter (POAG: 3.73 +/- 1.69 vs. 4.33 +/- 1.74 pixels; healthy: 5.61 +/- 1.02 vs. 6.47 +/- 1.20 pixels; both P < 0.001) of SC significantly increased after AE. In POAG, both treated and untreated with IOP-lowering medications, a significant reduction in mean IOP and increase in SC dimensions following AE were observed (all P < 0.05), and there were no significant differences of such measurements between the two subgroups (all P > 0.05).

Conclusion

AE-induced reduction in IOP and an increase in SC dimensions in POAG eyes as in healthy eyes. Further studies to evaluate the long-term effect of AE on IOP control and SC morphology in POAG seem warranted.

Study of the Prevalence of Glaucoma in Kazakhstan

BACKGROUND

Glaucoma is one of the leading causes of permanent visual disability around the world. However, the available literature lacks data on the prevalence of glaucoma in Central Asia, particularly in the Republic of Kazakhstan.

OBJECTIVE

The study was aimed at assessing the prevalence of glaucoma in the population of the Republic of Kazakhstan over 40 years old in 2019.

METHODS

A retrospective study was based on the analysis of the results of glaucoma screenings in 171 832 patients over 40 years old living in Kazakhstan (in 14 counties). Glaucoma cases were confirmed by Goldmann tonometry, fundus photography, and visual field testing. Demographic indicators, territorial differences, and hereditary predisposition were studied and analysed. In addition, blood pressure was measured.

RESULTS

Of 171 832 patients examined, 452 with verified glaucoma were identified. The average age of the patients was 63.9 ± 9.4. In rural areas, the prevalence of glaucoma was higher compared to the urban population. The overall prevalence of glaucoma among people over 40 years old was 2.37 ± 0.17. The prevalence of glaucoma among women was higher than for men, with an indicator of 1.91 (95% CI relative risk 1.78 - 2.03) (p < 0.05). The highest prevalence was found in the 71 - 75 age group [equals to 14.2% (95% CI 11.7 - 19.9)], with a statistically significant difference (p < 0.05). The highest prevalence of glaucoma was observed in the group of people with a hereditary predisposition, with an indicator of 14.7% (95% CI 0.6 - 1.9) (p < 0.05). Among all patients with concomitant arterial hypertension (n = 90, 19.9%), women (60%) compared with men (40%) had a 2.4% higher risk of glaucoma morbidity (95% CI 1.2% - 3.8%).

CONCLUSION

This study provides updated information on the prevalence of glaucoma in Kazakhstan. The results obtained confirm that the increase in the prevalence of glaucoma in Kazakhstan is directly proportional to the increase in the patients' age. These results showed the importance of screening for a timely diagnosis, especially for patients with high risk factors such as hereditary predisposition. Moreover, the results indicate that the early detection of systemic hypertension and increased intraocular pressure can be used for the prevention of undesirable outcomes such as an irreversible blindness.

Comparison of adherence between fixed and unfixed topical combination glaucoma therapies using Japanese healthcare/pharmacy claims database: a retrospective non-interventional cohort study

Background

Adherence to chronic therapies is crucial to prevent the progression of disease, such as glaucoma. However, only a limited number of studies have investigated them using real-world data in Japan. This study aimed to evaluate Japanese patients’ adherence to fixed- and unfixed-combination eye drops as a second-line therapy for glaucoma in real-world practice.

Methods

This retrospective, non-interventional cohort study utilized a commercially available Japanese healthcare database (MinaCare database). Medical/pharmacy claims data were collected from 2011 to 2016. The primary endpoint was adherence to medications, assessed by proportion of days covered (PDC) with medication during a 12-month post-index period. Meanwhile, the secondary endpoints included the persistence rate.

Results

A total of 738 patients were included in this study: 309 and 329 in the fixed- and unfixed-combination cohorts, respectively. Prostaglandin analog (PG)/β-blocker (BB) was most commonly claimed in 241/309 (78.0%) patients in the fixed-combination cohort. In the unfixed-combination cohort, PG and BB were claimed in 130/329 (39.5%) patients, whereas PG and α2-agonist were claimed in 87/329 (26.4%) patients. Patients were more adherent to the fixed-combination than the unfixed-combinations (mean PDCs [SD], 79.1% [32.1] vs. 62.2% [38.0]; P < 0.0001). The proportion of patients with good adherence (PDC ≥ 80%) was also higher in the fixed-combination cohort (69.6%) than in the unfixed-combination cohort (48.6%) (P < 0.0001). During the 12-month post-index period, the persistence rate was higher in the fixed-combination cohort than in the unfixed-combination cohort (47.6% [95% confidence intervals (CI): 41.9–53.0] vs. 24.9% [95% CI: 20.4–29.7], P < 0.0001).

Conclusions

Japanese patients with glaucoma preferred the fixed-combination therapies over the unfixed-combination therapies. Hence, fixed-combination therapies would contribute to the improvement of adherence.

Periodic normalization of the translaminar pressure gradient prevents glaucomatous damage

The 24-hour intraocular pressure (IOP) rhythm is of interest to clinicians but its overall impact on glaucomatous progression remains unclear. Recent evidence has implicated the translaminar pressure gradient (TLPG), or imbalance between IOP and intracranial pressure, in the development of glaucoma. Evidence suggests that retinal ganglion cell death occurs as a result of decreased axonal transport only after a sustained, elevated TLPG. We hypothesize that periodic normalization of the TLPG prevents glaucomatous damage by enabling temporary resumption of axonal transport. Temporary resumption of axonal transport allows for delivery of critical metabolic cargoes with concomitant removal of metabolic waste which prevents apoptosis of the retinal ganglion cell.

Global assessment of arteriolar, venular and capillary changes in normal tension glaucoma

Microcirculatory insufficiency has been hypothesized in glaucoma pathogenesis. There is a scarcity of data to comprehensively examine the changes in retinal microvasculature and its role in normal tension glaucoma (NTG). We conducted a cross-sectional case-control study and included 168 eyes from 100 NTG patients and 68 healthy subjects. Quantitative retinal arteriolar and venular metrics were measured from retinal photographs using a computer-assisted program. Radial peripapillary capillary network was imaged with OCT-A and quantitative capillary metrics (circumpapillary vessel density (cpVD) and circumpapillary fractal dimension (cpFD)) were measured with a customized MATLAB program. We found that NTG was associated with decreased arteriolar and venular tortuosity, arteriolar branching angle, cpVD and cpFD. Decreased venular caliber, arteriolar and venular branching angles, cpVD and cpFD were associated with thinner average RNFL thickness. Decreased arteriolar and venular branching angles, cpVD and cpFD were also associated with worse standard automated perimetry measurements (mean deviation and visual field index). Compared with retinal arteriolar and venular metrics, regression models based on OCT-A capillary metrics consistently showed stronger associations with NTG and structural and functional measurements in NTG. We concluded that NTG eyes showed generalized microvascular attenuations, in which OCT-A capillary metrics attenuations were more prominent and strongly associated with NTG.

Effective treatment of a normal-tension glaucoma patient with bilateral ab externo XEN Gel Stent implantation

Purpose

To provide the first report of effective use of bilateral XEN Gel Stent implantation using an ab externo open-conjunctival approach designed to improve bleb function and meet the uniquely low intraocular pressure requirements of a Japanese patient with normal-tension glaucoma refractory to topical medical therapy.

Observations

A 54-year-old phakic Japanese woman with severe normal-tension glaucoma on maximally tolerated medical therapy of four topical agents presented with above-goal intraocular pressures and new medication intolerances. She underwent bilateral ab externo open-conjunctival XEN Gel Stent implantation with tenectomy and sub-Tenon's injection of 40μg of mitomycin-C, which resulted in reduction of intraocular pressures by 41.2 and 28.6% to 10 and 10 mmHg in the right and left eyes, respectively at the most recent visit. Postoperatively, a diffuse filtering bleb with good morphology developed in both eyes. The procedure has so far allowed for complete cessation of all four topical medications for up to eight months following surgery without any serious complications.

Conclusions

This case illustrates the potential of Xen Gel Stent implantation through an ab externo, open-conjunctival approach to be an effective, simple alternative to trabeculectomy to meet the unique low-pressure requirements of normal-tension glaucoma patients with practical and safety benefits of a micro-invasive approach.