Open-Angle Glaucoma—An Epidemiologic Overview

Quality by design steered approach for co-encapsulation of timolol maleate and dorzolamide hydrochloride in injectable liposomes

Glaucoma is caused by high intraocular pressure, which can causes blindness. Combinations of timolol and dorzolamide are used for its treatment with a requirement of multiple dosing with dosing being twice or four times a day. Conventional eye drops have poor pre-corneal retention and is thus less available for action. This study utilizes principles of Quality by Design for formulation of injectable liposomes coloaded with timolol maleate and dorzolamide HCl, which overcomes limitations of conventional eye drops. For implementation of Quality by Design principles a systematic approach involving defining Quality Target Product Profile, identification of Critical Quality Attributes, mapping Critical Quality Attributes to Critical Process Parameters and Critical Material Attributes, Failure Mode and Effect Analysis based risk assessment, Taguchi screening, and 32 full factorial Design of Experiments design were utilized. A robust model for formulation of coloaded liposomes was successfully developed. Design of Experiments approach allowed to obtain optimized batch having particle size of 116.1 nm, encapsulation efficiency of dorzolamide HCl of 72.12 % and encapsulation efficiency of timolol maleate of 71.94 %. In-vitro drug release showed a sustained release for 4 days. The prepared formulation was in the desired osmolarity range. Biosafety was proved using histopathological characterization. In-vivo studies for assessing the Intra Ocular Pressure reduction showed that there was no significant difference in Intra Ocular Pressure reduction between prepared liposomes and marketed formulation but were superior than marketed formulation because of less fluctuations in Intra Ocular Pressure. Prepared coloaded injectable liposomes lays the foundation for further research in the area and can be translated from to bench side for commercial clinical use.

Aging and intraocular pressure homeostasis in mice

Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.

Recent updates on ocular disease management with ophthalmic ointments

Ophthalmic diseases can result in permanent vision loss and blindness. Convenient topical and systemic treatments are preferred to address these sight-threatening conditions. However, the unique anatomy of the eye presents challenges for drug delivery. Various ophthalmic ointment formulations have been developed to enhance bioavailability in the eye to prolong residence time and improve corneal permeability. This article explores a wide range of ocular diseases affecting individuals globally and how ointments are used to manage them. From eye to ocular barriers, this review focuses on published scientific research and formulation strategies for severe ocular complications using conventional topical ointments. Additionally, it delves through patented technologies and marketed formulations supporting the use of ointments in ocular drug delivery.

A Comparative Study on Efficacy of Intraocular Pressure Lowering of Two Fixed-Dose Antiglaucoma Drug Combination Brinzolamide-Brimonidine Versus Latanoprost-Timolol in Primary Open-Angle Glaucoma and Ocular Hypertension

Purpose: To compare the efficacy of Brinzolamide-Brimonidine (BB) (1%+0.2%) with the gold standard Latanoprost-Timolol (LT) (0.005%+0.5%) in treating primary open-angle glaucoma (POAG) and ocular hypertension (OHT). Methods: A 1-year prospective study, spanning from May 2022 to May 2023, conducted at a tertiary eye-care hospital. Participants, aged 40-60, with a baseline intraocular pressure (IOP) >21 mm Hg, requiring a >30% reduction, were enrolled. Group A (n = 100) received BB, and Group B (n = 100) received LT. Outcomes were assessed at 1 month (IOP difference from baseline), 3 and 6 months (mean diurnal variations). Results: The mean age at presentation was 55.5 ± 4.5 years in Group A and 54.7 ± 4.2 years in Group B. At 1 month, Group A exhibited a mean IOP of 18.7 mm Hg, while Group B had 17.6 mm Hg, with no statistically significant difference (P = 0.53). No significant diurnal variation was observed in either group (P = 0.07). Target pressure was achieved in 88% of patients in Group A and slightly higher at 92% in Group B. Moreover, no serious side effects were reported, and compliance was higher in Group B (98%) compared to Group A (96%). Conclusion: Although LT showed slightly better and sustained IOP reduction, the difference was not statistically significant. Both BB and LT demonstrated comparable outcomes for managing POAG and OHT.

IOP and glaucoma damage: The essential role of optic nerve head and retinal mechanosensors

There are many unanswered questions on the relation of intraocular pressure to glaucoma development and progression. IOP itself cannot be distilled to a single, unifying value, because IOP level varies over time, differs depending on ocular location, and can be affected by method of measurement. Ultimately, IOP level creates mechanical strain that affects axonal function at the optic nerve head which causes local extracellular matrix remodeling and retinal ganglion cell death - hallmarks of glaucoma and the cause of glaucomatous vision loss. Extracellular tissue strain at the ONH and lamina cribrosa is regionally variable and differs in magnitude and location between healthy and glaucomatous eyes. The ultimate targets of IOP-induced tissue strain in glaucoma are retinal ganglion cell axons at the optic nerve head and the cells that support axonal function (astrocytes, the neurovascular unit, microglia, and fibroblasts). These cells sense tissue strain through a series of signals that originate at the cell membrane and alter cytoskeletal organization, migration, differentiation, gene transcription, and proliferation. The proteins that translate mechanical stimuli into molecular signals act as band-pass filters - sensing some stimuli while ignoring others - and cellular responses to stimuli can differ based on cell type and differentiation state. Therefore, to fully understand the IOP signals that are relevant to glaucoma, it is necessary to understand the ultimate cellular targets of IOP-induced mechanical stimuli and their ability to sense, ignore, and translate these signals into cellular actions.

Myocilin Mutation N480K Leads to Early Onset Juvenile and Adult-onset Primary Open Angle Glaucoma in a Six Generation Family

PRCIS

A pathogenic autosomal dominant MYOC mutation N480K detected in 6 generations of an Indian family is primarily responsible for juvenile open angle glaucoma (JOAG) and adult-onset primary open angle glaucoma (POAG), emphasizing the importance of screening this mutation at a younger age.

PURPOSE

To screen myocilin mutations in a large South Indian family with early-onset JOAG and adult-onset POAG.

METHODS

In a large South Indian family with 20 members, 8 members diagnosed as JOAG, 7 members as POAG, 4 members as JOAG suspect, and 1 member as POAG suspect were screened for myocilin ( MYOC) mutations using Sanger sequencing. Whole exome sequencing was performed on clinically suspected JOAG/POAG individuals.

RESULTS

Myocilin gene mutation N480K (c.1440C>G) was detected in 20 family members, including proband, of whom 8 were JOAG and 7 were POAG patients, 3 were JOAG suspects, and 2 were unaffected. Among the unaffected carriers, 1 was less than 5 years old, and another was 25 years old. The earliest to develop the disease was a 10-year-old child. The penetrance of the mutation was 95% over 10 years of age. This family had JOAG/POAG suspects with no N480K MYOC mutation, and they were further screened for other mutations using whole-exome sequencing. Polymorphisms CYP1B1 L432V and MYOC R76K were detected in 3 JOAG/POAG suspects, and among these 3, one had another CYP1B1 polymorphic variant R368H. The presence of the CYP1B1 polymorphism along with an MYOC polymorphic variant among the JOAG/POAG suspects needs additional studies to explore their combined role in the onset of glaucoma.

CONCLUSIONS

This study reveals that MYOC mutation is primarily responsible for JOAG and adult-onset POAG in a family, emphasizing the importance of screening for this mutation at a younger age for early treatment.

Aging and intraocular pressure homeostasis in mice

Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.

The effect of a brinzolamide/brimonidine fixed combination on optic nerve head blood flow in rabbits

PURPOSE

The purpose of this study was to investigate the effect of a 1% brinzolamide and 0.1% brimonidine fixed combination (BBFC) on ONH blood flow (BF) in rabbits.

METHODS

A crossover study was conducted on pigmented rabbits; a physiological saline solution, brinzolamide, or BBFC was administered for eight days. ONH BF, intraocular pressure (IOP) and systemic parameters were measured before the eighth day's first dose and at 6, 9, 12, and 14 hours after the dose. ONH BF was assessed using laser speckle flowgraphy, and mean blur rate (MBR) values were calculated. The percentage against baseline of each parameter was calculated, and intergroup comparisons were performed at each time point.

RESULTS

There were no significant differences in the percentage change in systemic parameters. At 6 hours after administration, the BBFC group showed a significantly higher percentage change in large vessel area-MBR (%MV) compared to the control group (98.6±16.8%MV vs. 81.3±7.9%MV, P = 0.03). On the other hand, the brinzolamide group did not show a significant difference. Both the brinzolamide and BBFC groups had significantly lower percentage change in IOP (%IOP) compared to the control group (90.6±5.0%IOP, 93.3±2.9%IOP, and 99.2±1.7%IOP, respectively, P < 0.01).

CONCLUSION

BBFC effectively reduces IOP and mitigates diurnal fluctuation-induced decreases in ONH BF.

Paving the way while playing catch up: mitochondrial genetics in African ancestry primary open-angle glaucoma

Glaucoma, the leading cause of irreversible blindness worldwide, disproportionately affects individuals of African descent. Specifically, previous research has indicated that primary open-angle glaucoma (POAG), the most common form of disease, is more prevalent, severe, early-onset, and rapidly-progressive in populations of African ancestry. Recent studies have identified genetic variations that may contribute to the greater burden of disease in this population. In particular, mitochondrial genetics has emerged as a profoundly influential factor in multiple neurodegenerative diseases, including POAG. Several hypotheses explaining the underlying mechanisms of mitochondrial genetic contribution to disease progression have been proposed, including nuclear-mitochondrial gene mismatch. Exploring the fundamentals of mitochondrial genetics and disease pathways within the understudied African ancestry population can lead to groundbreaking advancements in the research and clinical understanding of POAG. This article discusses the currently known involvements of mitochondrial genetic factors in POAG, recent directions of study, and potential future prospects in mitochondrial genetic studies in individuals of African descent.

Neurovascular segregation of the retinal nerve fiber layer in glaucoma

The imaging data of one eye from 154 healthy and 143 glaucoma participants were acquired to evaluate the contributions of the neuronal and vascular components within the retinal nerve fiber layer (RNFL) for detecting glaucoma and modeling visual field loss through the use of optical coherence tomography (OCT) and OCT angiography. The neuronal and vascular components within the circumpapillary RNFL were independently evaluated. In healthy eyes, the neuronal component showed a stronger association with age (r = -0.52, p < 0.001) compared to measured RNFL thickness (r = -0.46, p < 0.001). Using the neuronal component alone improved detection of glaucoma (AUC: 0.890 ± 0.020) compared to measured RNFL thickness (AUC: 0.877 ± 0.021; χ2 = 5.54, p = 0.019). Inclusion of the capillary components with the sectoral neuronal component resulted in a significant improvement in glaucoma detection (AUC: 0.927 ± 0.015; χ2 = 15.34, p < 0.001). After adjusting for potential confounders, AUC increased to 0.952 ± 0.011. Results from modeling visual field loss in glaucoma eyes suggest that visual field losses associated with neuronal thinning were moderated in eyes with a larger capillary component. These findings suggest that segregation of the neurovascular components could help improve understanding of disease pathophysiology and affect disease management in glaucoma.

Proteomics-Based Identification of Retinal Protein Networks Impacted by Elevated Intraocular Pressure in the Hypertonic Saline Injection Model of Experimental Glaucoma

Elevated intraocular pressure is considered a major cause of glaucomatous retinal neurodegeneration. To facilitate a better understanding of the underlying molecular processes and mechanisms, we report a study focusing on alterations of the retina proteome by induced ocular hypertension in a rat model of the disease. Glaucomatous processes were modeled through sclerosing the aqueous outflow routes of the eyes by hypertonic saline injections into an episcleral vein. Mass spectrometry-based quantitative retina proteomics using a label-free shotgun methodology identified over 200 proteins significantly affected by ocular hypertension. Various facets of glaucomatous pathophysiology were revealed through the organization of the findings into protein interaction networks and by pathway analyses. Concentrating on retinal neurodegeneration as a characteristic process of the disease, elevated intraocular pressure-induced alterations in the expression of selected proteins were verified by targeted proteomics based on nanoflow liquid chromatography coupled with nano-electrospray ionization tandem mass spectrometry using the parallel reaction monitoring method of data acquisition. Acquired raw data are shared through deposition to the ProteomeXchange Consortium (PXD042729), making a retina proteomics dataset on the selected animal model of glaucoma available for the first time.

Long-term Impact of Immediate Versus Delayed Treatment of Early Glaucoma: Results From the Early Manifest Glaucoma Trial

PURPOSE

To compare long-term visual outcomes in the 2 arms of the Early Manifest Glaucoma Trial (EMGT) and determine if delayed treatment was associated with a penalty in terms of visual function.

DESIGN

Long-term follow-up of a prospective, randomized controlled clinical trial.

METHODS

EMGT was carried out at 2 centers in Sweden; 255 subjects with newly detected, untreated glaucoma were randomized to immediate treatment with topical betaxolol and argon laser trabeculoplasty or to no initial treatment as long as no progression was detected. Subjects were followed prospectively with standard automated perimetry, visual acuity measurements, and tonometry for up to 21 years. Outcomes included vision impairment (VI), the perimetric mean deviation (MD) index and rate of progression, and visual acuity.

RESULTS

At study end, percentages of eyes with VI or blindness were slightly higher in the treated group than in the untreated control group, 12.1% vs 11.0%, and 9.4.% vs 6.1% respectively, as were subjects with VI in at least one eye, 19.5% vs 18.7%. The differences were not statistically significant, nor were cumulative incidences of VI in at least one eye. The control group had more field loss than the treatment group, with median MD in the worse eye of -14.73 dB vs -12.85 dB, and rate of progression of -0.74 vs -0.60 dB/y, which was not statistically significant. Differences in visual acuity were minimal.

CONCLUSIONS

Delaying treatment did not result in serious penalties. VI occurred at similar proportions in both treatment arms with a slight preponderance in the treatment group, whereas visual field damage was slightly higher in the control group.

Vasoreactivity of the optic nerve head, nailfold, and facial skin in response to cold provocation in normal-tension glaucoma patients

BACKGROUND

The dysfunction of optic nerve head (ONH) hemodynamics has been suggested to be involved in the pathogenesis of normal-tension glaucoma (NTG). The aim of this study was to compare vasoreactivity in the ONH, nailfold, and facial skin in response to cold-water provocation in NTG patients and healthy controls.

METHODS

We performed cold-water provocation in 14 eyes of 14 NTG patients and 15 eyes of 15 age-matched control subjects. Laser speckle flowgraphy-derived tissue-area mean blur rate (MT), skin blood flowmetry-derived pulse wave amplitude (PA), nailfold capillaroscopy-derived nailfold capillary diameter, and other clinical parameters were recorded at baseline and 4 and 6 min after the cold stimulus. We compared changes (as percentages) in these variables in the NTG and control subjects with a linear mixed-effects model and evaluated correlations between these changes with Spearman's rank correlation coefficient.

RESULTS

The interaction term between the NTG group (reference, control group) and the 4-min protocol step (reference, baseline) significantly affected the changes in MT, nailfold capillary diameter and PA (β = -9.51%, P = 0.017, β = -20.32%, P = 0.002; β =  + 18.06%, P = 0.017, respectively). The change in MT was positively correlated with the change in nailfold capillary diameter, and negatively correlated with the change in PA (r = 0.39, P = 0.036; r = -0.40, P = 0.031, respectively).

CONCLUSION

NTG patients showed abnormal vasoconstriction in the ONH and nailfold and vasodilation in the facial skin in response to cold-water provocation.

Prevalence of Glu323Lys Mutation of the TIGR/MYOC Gene and Risk Factors amongst Primary Open-angle Glaucoma Patients in Ouagadougou, Burkina Faso

Aim

Glaucoma is a group of degenerative diseases of the optic nerve whose predisposing factors may be genetic. The objective of this study was to estimate the frequency of the Glu323Lys mutation as a genetic risk factor for glaucoma.

Materials and methods

A cross-sectional study over 6 months from October 2020 to March 2021 in Ouagadougou, Burkina Faso. A total of 89 samples of patients with primary open-angle glaucoma (POAG) were collected. The frequency of the Glu323Lys mutation of the myocilin, trabecular meshwork inducible glucocorticoid response (TIGR/MYOC) gene by polymerase chain reaction (PCR)-restriction fragment length polymorphism.

Results

In glaucoma patients, only homozygous nonmutated guanine-guanine (GG) and heterozygous mutated adenine-guanine (AG) genotypes were found in 96.63 and 3.37% of cases, respectively. Around 69.66% of patients had a family history of glaucoma, 28.09% had a history of hypertension, and 7.86% had a history of diabetes.

Conclusion

The frequency of the Glu323Lys mutation of the TIGR/MYOC gene was 3.37% in the glaucoma population in Ouagadougou. A case-control study is necessary to know the contribution of the Glu323Lys mutation as a genetic risk factor for glaucoma in our study population.

Clinical significance

This study constituted the beginning of genetic investigations of glaucoma in our context and showed a low Glu323Lys mutation.

How to cite this article

Traoré L, Sanou J, Bakyono BS, et al. Prevalence of Glu323Lys Mutation of the TIGR/MYOC Gene and Risk Factors amongst Primary Open-angle Glaucoma Patients in Ouagadougou, Burkina Faso. J Curr Glaucoma Pract 2023;17(2):79-84.

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.

Real-World Analysis on the Characteristics, Therapeutic Paths and Economic Burden for Patients Treated for Glaucoma in Italy

This real-world analysis was performed on administrative databases to evaluate characteristics, therapies, and related economic burden of glaucoma in Italy. Adults with at least 1 prescription for ophthalmic drops (ATC class S01E: antiglaucoma preparations, miotics) during data availability period (January 2010-June 2021) were screened, then patients with glaucoma were included. First date of ophthalmic drops prescription was the index date. Included patients had at least 12 months of data availability before index-date and afterwards. Overall, 18,161 glaucoma-treated patients were identified. The most frequent comorbidities were hypertension (60.2%), dyslipidemia (29.7%) and diabetes (17%). During available period, 70% (N = 12,754) had a second-line therapy and 57% (N = 10,394) a third-line therapy, predominantly ophthalmic drugs. As first-line, besides 96.3% patients with ophthalmic drops, a small proportion reported trabeculectomy (3.5%) or trabeculoplasty (0.4%). Adherence to ophthalmic drops was found in 58.3% patients and therapy persistence reached 78.1%. Mean total annual cost per patient was €1,725, mostly due to all-cause drug expenditure (€800), all-cause hospitalizations (€567) and outpatient services (€359). In conclusion, glaucoma-treated patients were mostly in monotherapy ophthalmic medications, with an unsatisfying adherence and persistence (<80%). Drug expenditures were the weightiest item among healthcare costs. These real-life data suggest that further efforts are needed to optimize glaucoma management.

Ocular Drug Delivery: a Comprehensive Review

The human eye is a sophisticated organ with distinctive anatomy and physiology that hinders the passage of drugs into targeted ophthalmic sites. Effective topical administration is an interest of scientists for many decades. Their difficult mission is to prolong drug residence time and guarantee an appropriate ocular permeation. Several ocular obstacles oppose effective drug delivery such as precorneal, corneal, and blood-corneal barriers. Routes for ocular delivery include topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral, and retrobulbar. More than 95% of marketed products exists in liquid state. However, other products could be in semi-solid (ointments and gels), solid state (powder, insert and lens), or mixed (in situ gel). Nowadays, attractiveness to nanotechnology-based carries is resulted from their capabilities to entrap both hydrophilic and lipophilic drugs, enhance ocular permeability, sustain residence time, improve drug stability, and augment bioavailability. Different in vitro, ex vivo, and in vivo characterization approaches help to predict the outcomes of the constructed nanocarriers. This review aims to clarify anatomy of the eye, various ocular diseases, and obstacles to ocular delivery. Moreover, it studies the advantages and drawbacks of different ocular routes of administration and dosage forms. This review also discusses different nanostructured platforms and their characterization approaches. Strategies to enhance ocular bioavailability are also explained. Finally, recent advances in ocular delivery are described.

A Randomized, Double-Masked, Active-Controlled, Crossover Phase III Equivalence Study of Generic Dorzolamide 2% versus Innovator Trusopt® Eye Drop Solution in Subjects with Open-Angle Glaucoma or Ocular Hypertension

Background

The aim of this study was to demonstrate the equivalence of generic dorzolamide 2% eye drops solution versus the innovator formulation (Trusopt® eye drops solution) in patients with open-angle glaucoma or ocular hypertension.

Methods

This prospective, monocentric, double-masked, active-controlled crossover phase III study included 32 patients. After washout, patients were randomized to reference product (Trusopt®) or test product (dorzolamide 2% eye drops, Rompharm Company SRL) for a 4-week period. Subsequent washout and crossover were performed. Drops were applied t.i.d. The primary efficacy endpoint was the difference in mean diurnal IOP. Goldmann applanation tonometry was performed at 8 am, 12 pm, and 4 pm at each visit, and safety was assessed by documentation of adverse events (AEs). Therapy adherence was documented by self-reporting and eye drop bottle weighing. An ANOVA with treatment, sequence, study period, and patient within the sequence as effects was performed and an additional post hoc ANCOVA including the baseline IOP was also performed.

Results

34 patients were randomized and analyzed in the safety population. The per-protocol population included 32 patients. According to the self-report, all patients were >80% compliant. Under the ANCOVA model, the 90% confidence interval for the average change of the IOP −0.27 mmHg (−1.17 mmHg–0.64 mmHg) is included by the acceptance range −1.5 mmHg to +1.5 mmHg after excluding 2 patients, which had falsely reported high therapy adherence. No clinically relevant difference was observed in frequency or severity of the AEs between both treatments.

Conclusions

This study showed the equivalence of the tested generic dorzolamide 2% eye drops solution to the reference product Trusopt® eye drops solution. Trial Registration. This trial is registered with (ClinicalTrials.gov (identifier: NCT00878917) on April 9, 2009).

Retinal ganglion cell-specific genetic regulation in primary open-angle glaucoma

To assess the transcriptomic profile of disease-specific cell populations, fibroblasts from patients with primary open-angle glaucoma (POAG) were reprogrammed into induced pluripotent stem cells (iPSCs) before being differentiated into retinal organoids and compared with those from healthy individuals. We performed single-cell RNA sequencing of a total of 247,520 cells and identified cluster-specific molecular signatures. Comparing the gene expression profile between cases and controls, we identified novel genetic associations for this blinding disease. Expression quantitative trait mapping identified a total of 4,443 significant loci across all cell types, 312 of which are specific to the retinal ganglion cell subpopulations, which ultimately degenerate in POAG. Transcriptome-wide association analysis identified genes at loci previously associated with POAG, and analysis, conditional on disease status, implicated 97 statistically significant retinal ganglion cell-specific expression quantitative trait loci. This work highlights the power of large-scale iPSC studies to uncover context-specific profiles for a genetically complex disease.

The genetic basis for adult onset glaucoma: Recent advances and future directions

Glaucoma, a diverse group of eye disorders that results in the degeneration of retinal ganglion cells, is the world's leading cause of irreversible blindness. Apart from age and ancestry, the major risk factor for glaucoma is increased intraocular pressure (IOP). In primary open-angle glaucoma (POAG), the anterior chamber angle is open but there is resistance to aqueous outflow. In primary angle-closure glaucoma (PACG), crowding of the anterior chamber angle due to anatomical alterations impede aqueous drainage through the angle. In exfoliation syndrome and exfoliation glaucoma, deposition of white flaky material throughout the anterior chamber directly interfere with aqueous outflow. Observational studies have established that there is a strong hereditable component for glaucoma onset and progression. Indeed, a succession of genome wide association studies (GWAS) that were centered upon single nucleotide polymorphisms (SNP) have yielded more than a hundred genetic markers associated with glaucoma risk. However, a shortcoming of GWAS studies is the difficulty in identifying the actual effector genes responsible for disease pathogenesis. Building on the foundation laid by GWAS studies, research groups have recently begun to perform whole exome-sequencing to evaluate the contribution of protein-changing, coding sequence genetic variants to glaucoma risk. The adoption of this technology in both large population-based studies as well as family studies are revealing the presence of novel, protein-changing genetic variants that could enrich our understanding of the pathogenesis of glaucoma. This review will cover recent advances in the genetics of primary open-angle glaucoma, primary angle-closure glaucoma and exfoliation glaucoma, which collectively make up the vast majority of all glaucoma cases in the world today. We will discuss how recent advances in research methodology have uncovered new risk genes, and how follow up biological investigations could be undertaken in order to define how the risk encoded by a genetic sequence variant comes into play in patients. We will also hypothesise how data arising from characterising these genetic variants could be utilized to predict glaucoma risk and the manner in which new therapeutic strategies might be informed.

[Factor analysis of the risk of developing primary open-angle glaucoma]

Primary open-angle glaucoma (POAG) is the most common form of glaucoma. Insufficient information about the pathogenetic aspects of POAG development necessitates further research of the main clinical, functional, and genetic risk factors for the disease development, as well as their correlations using modern methods of mathematical analysis.

PURPOSE

To assess the significance of risk factors in POAG development based on multivariate analysis of variance.

MATERIAL AND METHODS

The study included 348 patients (348 eyes) with stages I-IV POAG aged 45 to 87 years, who underwent a comprehensive ophthalmological and genetic examination. The control group consisted of 48 individuals (48 eyes) without glaucoma, matched with POAG patients in terms of gender and age. Ophthalmological examination of patients was carried out in 2013-2019 at the «Optimed» Laser Eye Surgery Center in Ufa, molecular genetic research - at the Institute of Biochemistry and Genetics of the Ufa Federal Research Center of the Russian Academy of Sciences. The results were statistically processed using the IBM SPSS Statistics v.21 program. The multivariate analysis employed the principal component method. Correlations between patient parameters and main factors were calculated using the method of rotation - varimax. The significance level was taken equal to 0.05 when testing statistical hypotheses.

RESULTS

Factor analysis was used to rank the factors associated with POAG development, the following variables were attributed to the most significant indicators of high risk (16.75% of the total variance) of developing the disease: age, comorbidity index, cataract, pseudoexfoliative syndrome, pigmentation intensity in the anterior chamber angle.

CONCLUSION

Factor analysis is a multivariate method of mathematical analysis that allows studying the role of the risk factors for POAG development and their association with the disease, which contributes to early diagnosis and identification of clinical and functional features of the disease.

Androgen deprivation therapy may reduce the risk of primary open-angle glaucoma in patients with prostate cancer: a nationwide population-based cohort study

Background

We evaluated the risk of developing primary open-angle glaucoma (POAG) according to androgen deprivation therapy (ADT) status in patients with prostate cancer.

Materials and methods

From the nationwide claims database in South Korea, 218,203 men with prostate cancer were identified between 2008 and 2017. After applying the inclusion and exclusion criteria, a total of 170,701 patients (42,877 in the ADT and non-ADT groups and 127,824 in the non-ADT group) were included in the analysis. To adjust for comorbidities between cohorts, exact matching was performed. Cox proportional hazard regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of POAG associated with ADT after controlling for potential confounding factors.

Results

In the matched cohort, the ADT group had a lower proportion of newly developed POAG than the non-ADT group (2.10% vs. 2.88%, respectively; P < 0.0001). Multivariable analysis revealed that the ADT group had a significantly lower risk of POAG than the non-ADT group (HR, 0.808; 95% CI, 0.739–0.884; P < 0.0001). The risk of POAG was lower in patients who underwent ADT for less than 2 years (HR, 0.782; 95% CI, 0.690–0.886; P = 0.0001) and in those receiving ADT for over 2 years (HR, 0.825; 95% CI, 0.744–0.916; P = 0.0003) compared with the non-ADT group.

Conclusions

The use of ADT was associated with a decreased risk of POAG in Korean patients with prostate cancer. Our findings suggest that testosterone may be involved in the pathophysiology of POAG, and this should be confirmed through further studies.

Evaluation of putative differences in vessel density and flow area in normal tension and high-pressure glaucoma using OCT-angiography

PURPOSE

To evaluate the putative differences in terms of vessel density and flow area between control (CTRL), high-pressure glaucoma (HPG) and normal tension glaucoma (NTG) subjects at macular and peripapillary level. To assess the correlation between Visual Field Index (VFI), the stage of glaucoma, and optical coherence tomography angiography (OCT-A) parameters.

MATERIAL AND METHODS

In this pilot, prospective study 46 eyes of 46 glaucomatous patients (19 NTG+27 HPG) and 25 control eyes (CTRL) of 25 subjects were recruited. All patients underwent a complete ophthalmologic examination and visual field testing. A 3×3mm volumetric macular scan (Angio Retina [3.0]) and a 4.5×4.5mm diameter peripapillary scan (Angio Disc [4.5]) were performed in the right eye using RTVue-XR Avanti (Optovue, Inc.) OCT-A.

RESULTS

Groups were homogeneous for age (P=0.784) and gender (P=0.623). Among the evaluated optic nerve head (ONH) and macular OCT-A parameters, ONH whole image (P<0.001), inside disc (P=0.021), peripapillary (P<0.001), ONH flow area (P<0.026), macula whole image (P<0.001), fovea (P<0.001), parafovea (P<0.001) showed a significant difference when CTRL group was compared to HPG group at the post hoc test. Similarly, ONH whole image (P<0.001), inside disc (P=0.005), peripapillary (P<0.001), ONH flow area (P<0.026), macula whole image (P<0.001), FOVEA (P<0.001), parafovea (P<0.001) showed a significant difference were CTRL were compared to NTG group. On the contrary, no significant difference was found when NTG and HPG groups were compared. Age was not significantly correlated with any of the OCT-A parameters. The stage of the disease showed a high, significant, correlation with ONH whole image (r=-0.81; P<0.0001), inside disc (r=-0.42; P<0.0001), peripapillary (r=-0.81; P<0.0001), RNFL (r=-0.79; P<0.0001), macula whole image (r=0.56; P<0.0001), fovea (r=-0.78; P<0.0001) and parafovea (r=0.67; P<0.0001). On the contrary, VFI showed a high, significant, correlation with ONH whole image (r=0.77; P<0.0001), inside disc (r=0.39; P=0.0018), peripapillary (r=0.713; P<0.0001), RNFL (r=0.63; P<0.0001), macula whole image (r=-0.39; P=0.0007), fovea (r=0.60; P<0.0001) and parafovea (r=-0.52; P<0.0001).

CONCLUSIONS

Our data support the usefulness of the OCT-A in the common clinical practice for diagnosis, staging, evaluating the progression of the disease as well as for better understanding of its pathogenic mechanisms.

Investigation of Key Signaling Pathways Associating miR-204 and Common Retinopathies

MicroRNAs are a large group of small noncoding RNAs that work in multiple cellular pathways. miR-204, as one of the key axes in the development, maintenance, and pathogenesis of the retina, plays several roles by modulating its target genes. This study was aimed at evaluating the target genes of miR-204 involved in the development and progression of common retinopathies such as glaucoma, retinoblastoma, and age-related macular degeneration. In this study, three datasets related to retinopathies (GSE50195, GSE27276, and GSE97508) were selected from Gene Expression Omnibus. miR-204 target genes were isolated from TargeScan. The shares between retinopathy and miR-204 target genes were then categorized. Using Enrichr and STRING, we highlighted the signaling pathways and the relationships between the proteins. SHC1 events in ERBB2, adherent junction's interactions, NGF signaling via TRKA from the plasma membrane, IRF3-mediated activation of type 1 IFN, pathways in upregulated genes and G0 and early G1, RORA-activated gene expression, PERK-regulated gene expression, adherent junction's interactions, and CREB phosphorylation pathways in downregulated genes were identified in glaucoma, retinoblastoma, and age-related macular degeneration. WEE1, SMC2, HMGB1, RRM2, and POLA1 proteins were also observed to be involved in the progression and invasion of retinoblastoma; SLC24A2 and DTX4 in age-related macular degeneration; and EPHB6, EFNB3, and SHC1 in glaucoma. Continuous bioinformatics analysis has shown that miR-204 has a significant presence and expression in retinal tissue, and approximately 293 genes are controlled and regulated by miR-204 in this tissue; also, target genes of miR-204 have the potential to develop various retinopathies; thus, a study of related target genes can provide appropriate treatment strategies in the future.

Twelve-Year Incidence of Open-angle Glaucoma: The Thessaloniki Eye Study

OBJECTIVE

The objective of this study was to determine the 12-year incidence of open-angle glaucoma (OAG), with further classification into primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG), in an elderly White population.

DESIGN

A longitudinal, population-based study in urban Northern Greece.

PARTICIPANT

Surviving cohort of the 2554 Thessaloniki Eye Study subjects 60 years and above who had the baseline examination.

METHODS

The surviving cohort was re-examined 12 years after baseline, using the same methodology and the same standard operating procedures as in the baseline examination. The definitions of glaucoma and pseudoexfoliation were consistent throughout the study. The 12-year incidences of OAG, POAG, and PEXG with corresponding 95% confidence intervals (CIs) were calculated for the whole study population, consisting of clinic-visit and home-visit participants. The population at risk was defined as those who did not meet the study criteria for the diagnosis of glaucoma in either eye at baseline.

MAIN OUTCOME MEASURES

Twelve-year incidence of OAG, with further classification into POAG and PEXG.

RESULTS

Of 1468 eligible subjects in the surviving cohort, 1092 were examined (participation rate 74%). Mean age at baseline was 68.9±4.6 years. Mean follow-up time was 11.6±1.6 years. The 12-year incidence of OAG was 4.4% (95% CI: 3.3-5.8); 0.37% per year. In the overall population the incidence of POAG and PEXG was 2.1% (95% CI: 1.3-3.2) and 2.3% (95% CI: 1.5-3.4), respectively. The corresponding incidence proportions were 2.9 (95% CI: 1.8-4.3) in those without PEX and 8.9 (95% CI: 5.8-12.9) in those with PEX at baseline and/or incidence. The latter was strongly associated with higher odds for incident glaucoma (odds ratio=3.34, 95% CI: 1.83-6.08, P<0.001). Of all incident OAG cases, 11.1% (95% CI: 4.4-24) had baseline intraocular pressure >21 mm Hg.

CONCLUSIONS

The incidence of OAG was similar or higher compared with other White populations. The incidence of glaucoma in those with PEX was higher compared with the incidence of glaucoma in those without PEX.

Pathophysiology of the comorbidity of glaucoma with obstructive sleep apnea: A postulation

Glaucoma is a serious and progressive optic neuropathy, the exact pathophysiology of which is still poorly understood. Furthermore, glaucoma exhibits significant comorbidity with obstructive sleep apnea (OSA) that warrants an in-depth study in view of highly probable beneficial and far-reaching clinical implications. In this brief paper, the authors have studied the existing theories in an attempt to explain the comorbidity and its underlying pathophysiology. From the ensuing evidence, the role of connective tissue strength has emerged as a major factor and which appears to play a pivotal role not only in the development of glaucoma but also in the underlying pathophysiology of its enigmatic comorbidity with OSA. Understanding the pathophysiology of the comorbidity can stimulate newer therapeutic strategies targeted toward strengthening of connective tissues that may at least retard if not arrest the progression of glaucomatous changes and their complications.

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.

The Effect of Medical Lowering of Intraocular Pressure on Peripapillary and Macular Blood Flow as Measured by Optical Coherence Tomography Angiography in Treatment-naive Eyes

PRCIS

Reduction of intraocular pressure (IOP) by latanoprost in treatment-naive eyes is significantly correlated to an increase in vessel density (VD) at the optic nerve head (ONH).

PURPOSE

To evaluate the effect of topical latanoprost on ocular microvasculature using optical coherence tomography angiography (OCTA).

PATIENTS AND METHODS

In this prospective case-control study, 26 eyes from 18 treatment-naive subjects in whom prostaglandin analogue (PGA) latanoprost 0.005% was initiated were included as cases. In 10 out of the 18 subjects, medication was initiated in only 1 eye; their contralateral untreated eyes were used as controls. OCTA (AngioVue, Optovue Inc., Fremont, CA) was performed at baseline and ≥3 weeks after commencing treatment. Main outcome measures were change in flow area and VD at the ONH, radial peripapillary capillaries (RPC), and macula. Comparison between the 2 visits was performed using a linear mixed model adjusted for intereye correlation and mean ocular perfusion pressure.

RESULTS

IOP decreased by 26.1%±11.3% (P<0.001) in the cases and 0.18%±12.2% (P=0.63) in controls. Significant correlations between change in IOP and change in ONH VD (correlation coefficient [r]=-0.42, P=0.04), and between change in IOP and change in RPC VD (r=-0.48, P=0.02) were observed in the cases, whereas none were observed in the controls. When multiple testing was considered, no significant changes in flow area and VD were observed in cases and controls.

CONCLUSIONS

The reduction of IOP by a PGA in treatment-naive eyes was significantly correlated to the increase in ONH VD and RPC VD. This may indicate a mechanism by which IOP reduction modulates the risk of glaucoma progression by improving ocular microperfusion.

Melatonin mitigates disrupted circadian rhythms, lowers intraocular pressure, and improves retinal ganglion cells function in glaucoma

Glaucoma is a progressive optic neuropathy associated with damage to retinal ganglion cells (RGCs) and disrupted circadian rhythms. Melatonin is a promising substance to ameliorate glaucoma-associated compromised circadian rhythms, sleep, mood, and retinal cells function. However, studies estimating melatonin effects in glaucoma are currently lacking. Therefore, In this study, we investigated the effect of long-term (daily at 10:30 pm for 90 days) oral melatonin administration on systemic (Tb) and local to the organ of vision (IOP) circadian rhythms, pattern electroretinogram (PERG), sleep, and mood, depending on glaucoma stage in patients diagnosed with stable or advanced primary open-angle glaucoma. In a laboratory study in 15 of them, 24-hour records of salivary melatonin were obtained and MTNR1B receptor gene polymorphism was assessed. Melatonin increased the stability of the Tb circadian rhythm by improving its phase alignment and alignment with IOP. Melatonin time-dependently decreased IOP and IOP standard deviation (SD). IOP 24-hour mean and IOP SD decreases were more pronounced in individuals with the higher initial 24-hour IOP mean. Melatonin improved RGCs function in advanced glaucoma; N95 amplitude increase correlated positively with RGCs loss. The beneficial effects of melatonin on sleep and mood were greater in advanced glaucoma. Finally, delayed salivary melatonin and Tb phases were observed in MTNR1B G-allele carriers with advanced glaucoma. Combined, these results provide evidence for melatonin efficiency in restoring disrupted circadian rhythms in glaucoma with different effects of melatonin on systemic vs. local circadian rhythms, indicating that a personalized strategy of melatonin administration may further refine its treatment benefits.

Medication Adherence and Persistence of Open-Angle Glaucoma Patients in Korea: A Retrospective Study Using National Health Insurance Claims Data

This study aimed to analyze medication adherence and persistence among open-angle glaucoma patients in Korea. A retrospective study was conducted using the Korean National Health Insurance (NHI) claims database from 2016 to 2019. Newly diagnosed open-angle glaucoma patients who were prescribed with the intraocular pressure (IOP)-lowering eyedrops were included. Adherence was measured using the medication possession ratio (MPR), and persistence was measured using the duration of therapy during the 24 month follow-up period. During the study period, 14,648 open-angle glaucoma patients were identified, and 3118 (21.3%) and 4481 patients (30.6%) were adherent to and persistent with their glaucoma treatment, respectively. The mean MPR was 48.8%, and the mean duration of therapy was 357.2 days. Logistic regression analysis showed that patients who are older, female, using prostaglandins as the index medication, and visiting secondary or tertiary hospitals were significantly associated with greater rates of adherence (odds ratio (OR) = 1.21, 1.12, 1.27, and 1.73, respectively) and persistence (OR = 1.11, 1.17, 1.16, 1.17, and 1.36, respectively) during the study period. Patients with open-angle glaucoma in Korea had substandard medication adherence and discontinued their treatment. Ophthalmologists should pay more attention to younger, male patients to improve adherence.

Comparison of ophthalmic artery blood flow between open-angle glaucoma and nonglaucomatous eyes of Indian patients

This study was undertaken to compare ophthalmic artery blood flow in eyes having primary open angle glaucoma (POAG) with age matched non glaucomatous eyes using the technique of Color Doppler imaging in Indian patients. One hundred patients of either sex over 40 years of age were divided into two groups of 50 patients each. Group 1 included 50 patients diagnosed with POAG whereas group 2 included patients who did not have POAG. Tests like visual fields and OCT RNFL were conducted and a radiologist assessed the ophthalmic artery blood flow using Color Doppler imaging. Hemodynamic calculations of ocular blood flow were done using the parameters of resistivity index (RI) and pulsatility index (PI). Statistically significant increase in the values of RI and PI were noted in patients with POAG as compared to those who did not have POAG.

Smarce1 and Tensin 4 Are Putative Modulators of Corneoscleral Stiffness

The biomechanical properties of the cornea and sclera are important in the onset and progression of multiple ocular pathologies and vary substantially between individuals, yet the source of this variation remains unknown. Here we identify genes putatively regulating corneoscleral biomechanical tissue properties by conducting high-fidelity ocular compliance measurements across the BXD recombinant inbred mouse set and performing quantitative trait analysis. We find seven cis-eQTLs and non-synonymous SNPs associating with ocular compliance, and show by RT-qPCR and immunolabeling that only two of the candidate genes, Smarce1 and Tns4, showed significant expression in corneal and scleral tissues. Both have mechanistic potential to influence the development and/or regulation of tissue material properties. This work motivates further study of Smarce1 and Tns4 for their role(s) in ocular pathology involving the corneoscleral envelope as well as the development of novel mouse models of ocular pathophysiology, such as myopia and glaucoma.

Association between Systemic Antioxidant Capacity and Retinal Vessel Diameters in Patients with Primary-Open Angle Glaucoma

The retinal vessel narrowing may be implicated in the pathogenesis of glaucoma; however, the association between systemic oxidative stress and retinal vessel diameter remains largely unknown. We examined the relationship between serum oxidative stress markers and retinal vessel diameters in eyes with primary open-angle glaucoma (POAG) and cataract, using central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE). We included 66 eyes of 66 patients with POAG (37 men, 29 women; 65.4 ± 11.7 years) and 20 eyes of 20 patients with cataract (7 men, 13 women; 69.4 ± 9.0 years) as the controls. The CRAE (p < 0.0001), CRVE (p < 0.0001), and serum biological antioxidant potential (BAP) (p = 0.0419) were significantly lower in the POAG group compared to the controls. The BAP showed significant correlation both with CRAE (ρ = 0.2148, p = 0.0471) and systolic blood pressure (ρ = −0.2431, p = 0.0241), while neither Diacron reactive oxygen metabolites nor sulfhydryl test correlated with them. The multivariate analyses indicated that age, best corrected visual acuity, and BAP were independent factors for CRAE or CRVE. The present study suggested that lower systemic antioxidant capacity was significantly associated with the intraocular pressure-independent vascular narrowing in POAG patients. This study provided a novel insight into the pathophysiology of glaucoma and highlighted the clinical impact on systemic antioxidant treatment for patients with glaucoma.

Evaluation of Redox Profiles of the Serum and Aqueous Humor in Patients with Primary Open-Angle Glaucoma and Exfoliation Glaucoma

Oxidative stress is thought to play a significant role in the development of glaucoma. However, the association between systemic and local oxidative stresses in different types of glaucoma has not been assessed fully. The current study compared the redox status in the aqueous humor (AH) and blood samples among eyes with primary open-angle glaucoma (POAG), exfoliation glaucoma (EXG), and non-glaucomatous controls to evaluate the relationship among systemic redox status, intraocular oxidative stress, and clinical backgrounds. AH and blood samples were obtained from 45 eyes of 45 Japanese subjects (15 POAG, 15 EXG, and 15 control eyes). The serum levels of lipid peroxides, ferric-reducing activity, and thiol antioxidant activity were measured by diacron reactive oxygen metabolites (dROM), biologic antioxidant potential (BAP), and sulfhydryl (SH) tests, respectively, using a free radical analyzer. The activities of cytosolic and mitochondrial forms of the superoxide dismutase (SOD) isoforms, i.e., SOD1 and SOD2, respectively, in AH and serum were measured using a multiplex bead immunoassay. In AH, SOD1 in subjects with EXG and SOD2 in those with POAG and EXG were significantly higher than in control eyes. In serum, compared to control subjects, BAP in subjects with POAG and EXG was significantly lower; SOD1 in those with EXG and SOD2 in those with POAG and EXG were significantly higher. dROM and SH did not differ significantly among the groups. The BAP values were correlated negatively with the SOD1 concentrations in AH and serum, SOD2 in the AH, intraocular pressure, and number of antiglaucoma medications. In conclusion, lower systemic antioxidant capacity accompanies up-regulation of higher local antioxidant enzymes, suggesting increased oxidative stress in eyes with OAG, especially in EXG. Determination of the systemic BAP values may help predict the redox status in AH.

Primary open angle glaucoma management in a tertiary eye care center in Saudi Arabia: a best practice implementation pilot project

AIM

Primary open angle glaucoma (POAG) is a leading cause of permanent visual loss affecting significant numbers in Saudi Arabia. There is no cure for glaucoma but there is mounting evidence to guide ophthalmologists in diagnosing and managing this disease. The aim of this pilot project was to assess the compliance with evidence-based criteria and to implement an adapted clinical practice guideline (CPG) for the management of patients with POAG at a tertiary eye care center in Riyadh, Saudi Arabia that will lead to improving quality, consistency and optimizing patients' care.

METHODS

The project consisted of three phases using audit and feedback strategy. It has utilized the Joanna Briggs Institute Practical Application of Clinical Evidence System and Getting Research into Practice audit and feedback tool. Eleven evidence-based audit criteria were developed. A baseline audit was then conducted. Barriers behind areas of noncompliance were identified and a number of strategies were implemented to overcome them. A follow-up postimplementation audit was then conducted.

RESULTS

Twenty electronic medical files were randomly selected for baseline audit. The results of the audit have identified a number of possible areas to improve in the diagnosis and management of POAG in compliance with the adapted CPG with compliance rate as low as 20% (4/20) in some criteria. Multifaceted interventions were implemented targeting mainly attitude and lack of knowledge and time and resource barriers. Significant improvement occurred in most criteria audited postimplementation.

CONCLUSION

The project demonstrates that audit and feedback is a feasible and effective tool to change glaucoma practice in a teaching hospital in Saudi Arabia. The success was due to multifaceted interventions including clear communication to promote awareness, an easily accessible CPG, and regular reminders to improve knowledge and change behavior. We propose our pilot implementation to be generalized to promote implementing evidence-based ophthalmology.

Retinal Nerve Fiber Layer Thickness in Healthy Eyes of Black, Chinese, and Latino Americans: A Population-Based Multiethnic Study

PURPOSE

To compare peripapillary retinal nerve fiber layer (RNFL) thickness among healthy adults by race and ethnicity and to identify determinants of RNFL thickness.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

Data from 6133 individuals (11 585 eyes) from 3 population-based studies in Los Angeles County, California, 50 years of age or older and of self-described African, Chinese, or Latin American ancestry.

METHODS

We measured RNFL thickness and optic nerve head parameters using the Cirrus HD-OCT 4000. Multivariate linear mixed regression was used to evaluate factors associated with RNFL thickness among participants without ocular diseases.

MAIN OUTCOME MEASURES

Determinants and modifiers of RNFL thickness.

RESULTS

The mean age of the participants was 60.1 years (standard deviation, 7.4 years). Black Americans showed the lowest RNFL thickness and smallest cup-to-disc ratio (CDR), and Chinese Americans showed the largest CDR and disc area after adjusting for age and gender (all P < 0.05). Per each 10-year older age group, the average RNFL thickness was 2.5 μm (95% confidence interval [CI], 1.8-3.1 μm), 2.8 μm (95% CI, 2.3-3.3 μm), and 3.5 μm (95% CI, 2.9-4.1 μm) thinner for Black, Chinese, and Latino Americans, respectively (age trend P < 0.05 and interaction P = 0.041). Black Americans compared with Chinese Americans, older age, male gender, hypertension, diabetes, greater axial length (AL), bigger disc area, and lower scan signal strength were associated with thinner average RNFL. Race, age, AL, disc area, and scan signal strength consistently were associated with RNFL thickness in all quadrants, whereas gender, hypertension, and diabetes were associated with RNFL thickness in select quadrants. Age and race explained the greatest proportion of variance of RNFL thickness.

CONCLUSIONS

Clinically important differences in RNFL thickness are present in healthy adults 50 years of age or older from different racial and ethnic groups of the same age, with the thinnest measures observed in Black Americans. This difference remains after accounting for disc size and AL. Furthermore, age-related RNFL thinning differs by race and ethnicity. Longitudinal studies are needed to verify our findings and to assess the influence of race and ethnicity in the clinical application of RNFL thickness.

Elevated intraocular pressure induces neuron-specific β-III-tubulin expression in non-neuronal vascular cells

PURPOSE

Pathological alterations within optic nerve axons and progressive loss of the parental retinal ganglion cell (RGC) bodies are characteristics of glaucomatous neuropathy. Abnormally elevated intraocular pressure (IOP) is thought to be the major risk factor for most forms of glaucomatous changes, while lowering of the IOP is the mainstream of treatment. However, the pathophysiological mechanisms involved in neurodegenerative changes are poorly understood. It remains still a matter of debate whether elevated IOP harms the neurons directly or indirectly through alterations in the retinal vascularization.

METHODS

We analysed morphological and molecular changes within the retina exposed to elevated IOP in an animal model of glaucoma in vivo, in retinal explants and in cultured dissociated retinal cells each incubated under elevated air pressure in vitro, imitating elevated IOP.

RESULTS

Although ß-III-tubulin expressing RGCs decreased within the course of the disease, total amount of ß-III-tubulin protein within the retina increased, leading to the assumption that other cells than RGCs abnormally express ß-III-tubulin due to elevated IOP. Surprisingly, we found that β-III-tubulin, a marker developmentally regulated and specifically expressed in neurons under normal conditions, was strongly up-regulated in desmin-, PDGFR-β- and α-SMA-positive pericytes as well as in endothelin-1-positive endothelial cells both in vivo under elevated IOP and in vitro under elevated culture atmosphere pressure that simulated IOP elevation. Beta-III-tubulin-driven signalling pathways (ERK 1/2, pERK1/2 and cdc42/Rac) were also regulated.

CONCLUSION

The unprecedented regulation of neuron-specific β-III-tubulin in pericytes and endothelial cells is likely associated with a role of the retinal vasculature in the IOP-induced development and manifestation of glaucomatous degenerative optic nerve response.

Bioenergetic shift and actin cytoskeleton remodelling as acute vascular adaptive mechanisms to angiotensin II in murine retina and ophthalmic artery

Ocular vascular dysfunction is a major contributing factor to the pathogenesis of glaucoma. In recent years, there has been a renewed interest in the role of angiotensin II (Ang II) in mediating the disease progression. Despite its (patho)physiological importance, the molecular mechanisms underlying Ang II-mediated oxidative stress remain largely unexplored in the ocular vasculature. Here, we provide the first direct evidence of the alterations of proteome and signalling pathways underlying Ang II-elicited oxidative insult independent of arterial pressure changes in the ophthalmic artery (OA) and retina (R) employing an in vitro experimental model. Both R and OA were isolated from male C57Bl/6J mice (n = 15/group; n = 5/biological replicate) and incubated overnight in medium containing either vehicle or Ang II (0.1 μM) at physiological conditions. Label-free quantitative mass spectrometry (MS)-based proteomics analysis identified a differential expression of 107 and 34 proteins in the R and OA, respectively. Statistical and bioinformatics analyses revealed that protein clusters involved in actin cytoskeleton and integrin-linked kinase signalling were significantly activated in the OA. Conversely, a large majority of differentially expressed retinal proteins were involved in dysregulation of numerous energy-producing and metabolic signalling pathways, hinting to a possible shift in retinal cell bioenergetics. Particularly, Ang II-mediated downregulation of septin-7 (Sept7; p < 0.01) and superoxide dismutase [Cu-Zn] (Sod1; p < 0.05), and upregulation of troponin T, fast skeletal muscle (Tnnt3; p < 0.05) and tropomyosin alpha-3 chain (Tpm3; p < 0.01) in the OA, and significant decreased expressions of two crystallin proteins (Cryab; p < 0.05 and Crybb2; p < 0.0001) in the R were verified at the mRNA level, corroborating our proteomics findings. In summary, these results demonstrated that exogenous application of Ang II over an acute time period caused impairment of retinal bioenergetics and cellular demise, and actin cytoskeleton-mediated vascular remodelling in the OA.

•

Acute Ang II stimulation elicits oxidative stress in ocular vasculature without pressor effect. .

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Dysregulation of energy-producing and metabolic pathways are implicated in the retina. .

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Actin cytoskeleton remodelling are vascular adaptation processes in the ophthalmic artery. .

The Effects of Glaucoma on the Pressure-Induced Strain Response of the Human Lamina Cribrosa

Purpose

To measure the ex vivo pressure-induced strain response of the human optic nerve head and analyze for variations with glaucoma diagnosis and optic nerve axon damage.

Methods

The posterior sclera of 16 eyes from 8 diagnosed glaucoma donors and 10 eyes from 6 donors with no history of glaucoma were inflation tested between 5 and 45 mm Hg. The optic nerve from each donor was examined for degree of axon loss. The posterior volume of the lamina cribrosa (LC) was imaged with second harmonic generation and analyzed using volume correlation to calculate LC strains between 5 and 10 and 5 and 45 mm Hg.

Results

Eye length and LC area were larger in eyes diagnosed with glaucoma (P ≤ 0.03). Nasal-temporal EXX and circumferential Eθθ strains were lower in the LC of diagnosed glaucoma eyes at 10 mm Hg (P ≤ 0.05) and 45 mm Hg (P ≤ 0.07). EXX was smaller in the LC of glaucoma eyes with <25% axon loss compared with undamaged normal eyes (P = 0.01, 45 mm Hg). In general, the strains were larger in the peripheral than central LC. The ratio of the maximum principal strain Emax in the peripheral to central LC was larger in glaucoma eyes with >25% axon loss than in glaucoma eyes with milder damage (P = 0.004, 10 mm Hg).

Conclusions

The stiffness of the LC pressure-strain response was greater in diagnosed glaucoma eyes and varied with glaucomatous axon damage. Lower LC strains in glaucoma eyes with milder damage may represent baseline biomechanical behavior that contributes to axon loss, whereas greater LC strain and altered radial LC strain variation in glaucoma eyes with more severe damage may be caused by glaucoma-related remodeling.

Relationships between Obesity, Nutrient Supply and Primary Open Angle Glaucoma in Koreans

To investigate the association between nutrient intake and primary open angle glaucoma (POAG) in Koreans, a population-based, cross-sectional survey, the Korean National Health and Nutrition Examination Survey, was analyzed. Glaucoma diagnosis was based on criteria established by the International Society of Geographic and Epidemiologic Ophthalmology. Multivariate regression analysis was used to assess the correlation between dietary intake and the prevalence of POAG in all enrolled subjects. In the low Body mass index(BMI) group (BMI <18.5), females with POAG had significantly lower intakes of energy, protein, fat, carbohydrate, ash, calcium, phosphorus, sodium, potassium, vitamin A, B-carotene, thiamin, riboflavin, and vitamin C than their non-glaucoma counterparts, based on a multivariate logistic regression analysis (all p < 0.05). In females with a medium BMI (18.5 ≤ BMI < 23), POAG showed a significant association with lower food intake, energy, protein, calcium, phosphorus, potassium, thiamin and niacin. (all p < 0.05). Lower protein thiamine intake in medium BMI males was related to POAG. Low dietary intake of several nutrients showed an association with glaucoma in low BMI female subjects. An insufficient intake of certain nutrients may be associated with an increased risk of glaucoma in Koreans. Further large-scale cohort studies are needed to determine how specific nutrients alter the risk of glaucoma.

Iatrogenic ophthalmic artery occlusion and retinal artery occlusion

Iatrogenic ophthalmic artery occlusion (IOAO) is a rare but devastating ophthalmic disease that may cause sudden and permanent visual loss. Understanding the possible etiologic modalities and pathogenic mechanisms of IOAO may prevent its occurrence. There are numerous medical etiologies of IOAO, including cosmetic facial filler injection, intravascular procedures, intravitreal gas or drug injection, retrobulbar anesthesia, intraarterial chemotherapy in retinoblastoma. Non-ocular surgeries and vascular events in arteries that are not directly associated with the ophthalmic artery, can also cause IOAO. Since IOAO has a limited number of treatment modalities, which lead to poor final visual prognosis, it is imperative to acknowledge the information regarding medical procedures that are etiologically associated with IOAO. We accumulated all searchable and available IOAO case reports (our cases and previous reported cases from the literature), classified them according to their mechanisms of pathogenesis, and summarized treatment options and responses of each of the causes. Various sporadic cases of IOAO can be categorized into three mechanisms as follows: intravascular event, orbital compartment syndrome, and increased intraocular pressure. Embolic IOAO, which is considered the primary cause of the condition, was classified into three subgroups according to the pathway of embolic movement (retrograde pathway, anterograde pathway, pathway through collateral channels). Despite the practical limitations of treating spontaneous (non-iatrogenic) retinal artery occlusion, this article will contribute in predicting and improving the prognosis of IOAO by recognizing the treatable factors. Furthermore, it is expected to provide clues to future research associated with the treatment of retinal artery occlusion.

The role of intracranial pressure in glaucoma and therapeutic implications

Despite glaucoma being the second leading cause of blindness globally, its pathogenesis remains incompletely understood. Although intraocular pressure (IOP) contributes to glaucoma, and reducing IOP slows progress of the disease, some patients progress despite normal IOP (NTG). Glaucomatous damage causes characteristic cupping of the optic nerve where it passes through the lamina cribrosa. There is evidence that cerebrospinal fluid (CSF) within the optic nerve sheath has a different composition from CSF surrounding the brain. Furthermore, fluctuations in CSF flow into the optic nerve sheath may be reduced by trabeculae within the sheath, and on standing intracranial pressure (ICP) within the sheath is stabilised at around 3 mmHg due to orbital pressure. Blood pressure has been linked both to glaucoma and ICP. These facts have led some to conclude that ICP does not play a role in glaucoma. However, according to stress formulae and Laplace's Law, stress within the lamina cribrosa is dependent on the forces on either side of it, (IOP and ICP), and its thickness. On lying flat at night, ICP between the brain and optic nerve sheath should equalise. Most evidence suggests ICP is lower in glaucoma than in control groups, and that the lamina cribrosa is thinner and more posteriorly displaced in glaucoma. Subjects who have had ICP reduced have developed signs of glaucoma. This review finds most evidence supports a role for low ICP in the pathogenesis of glaucoma. Caffeine, theophylline and vitamin A may increase ICP, and could be new candidates for an oral treatment.

Immediate Changes in Peripapillary Retinal Vasculature after Intraocular Pressure Elevation -an Optical Coherence Tomography Angiography Study

Purpose: To investigate changes in peripapillary retinal vessel density after acute intraocular pressure (IOP) elevation caused by laser peripheral iridotomy (LPI) in primary angle-closure suspects (PACS) by optical coherence tomography angiography (OCTA).Materials and Methods: Ninety-seven participants with PACS were included in this cross-sectional observational study. OCTA and IOP measurement were performed at baseline and 1 h after LPI. PACS eyes were further divided into three groups according to IOP increase 1 h after LPI (group 1 = IOP elevation <5 mmHg, 42eyes; group 2 = IOP elevation ≥5 mmHg and <10 mmHg, 34 eyes; group 3 = IOP elevation ≥10 mmHg, 21eyes). The changes of vessel density in radial peripapillary capillary (RPC) and entire retina were compared among groups.Results: When all eyes were included, the vessel density of RPC and entire retina 1 h after LPI were significantly decreased compared to the baseline (RPC: 64.5 ± 7.9 vs.67.8 ± 6.8, P < .001; retina: 86.3 ± 4.6 vs.88.3 ± 3.8, P < .001). There were significant differences among the three groups in the RPC and retinal vessel density at 1 h after LPI (RPC: 67.4 ± 7.3 vs. 63.2 ± 7.6 vs. 60.9 ± 7.5, P = .003; retinal: 87.7 ± 4.0 vs. 85.8 ± 4.5 vs. 84.3 ± 5.2, P = .015). In group 2 with an increased IOP from 5 mmHg to 10 mmHg, the reduction of vessel density in the RPC was more significant than that of the entire retina (RPC vs. retina: 7.1 ± 10.0% vs. 3.0 ± 4.4%, P = .006).Conclusions: LPI-induced IOP spikes resulted in a decrease in retina vessel density with PACS eyes by OCTA. The reduction of RPC vessel density was more significant than that of the entire retina in the subgroup of IOP increase from 5 to 10 mmHg. This suggests that vessel density in RPC was more sensitive to IOP increase than that of the entire retina in the peripapillary area.

Noninvasive Detection of Mitochondrial Dysfunction in Ocular Hypertension and Primary Open-angle Glaucoma

PURPOSE

To assess mitochondrial dysfunction in vivo in ocular hypertension (OHT) and primary open-angle glaucoma (POAG) using retinal metabolic analysis.

PATIENTS AND METHODS

This was an observational, cross-sectional study performed from November 2015 to October 2016 at the New York Eye and Ear Infirmary of Mount Sinai. Thirty-eight eyes with varying stages of POAG, 16 eyes with OHT, and 32 control eyes were imaged on a custom fundus camera modified to measure full retinal thickness fluorescence at a wavelength optimized to detect flavoprotein fluorescence (FPF). Optical coherence tomography was used to measure the retinal ganglion cell-plus layer (RGC+) thickness. Macular FPF and the ratio of macular FPF to RGC+ thickness were the primary outcome variables and were compared among the three groups using an age-adjusted linear regression model. A mixed-effects model was used to assess correlations between FPF variables and clinical characteristics.

RESULTS

Both macular FPF and the macular FPF/RGC+ thickness ratio were significantly increased in OHT compared with control eyes (P<0.05 and <0.01, respectively). In POAG eyes, macular FPF was not significantly increased compared with controls (P=0.24). However, the macular FPF/RGC+ thickness ratio in POAG eyes was significantly increased compared with controls (P<0.001). FPF was significantly correlated to age in POAG eyes.

CONCLUSIONS

Despite lacking clinical evidence of glaucomatous deterioration, OHT eyes displayed significantly elevated macular FPF, suggesting that mitochondrial dysfunction may be detected before structural changes visible on current clinical imaging. Our preliminary results suggest that macular FPF analysis may prove to be a useful tool in assessing and evaluating OHT and POAG eyes.

Lifetime Risk of Visual Impairment Resulting from Glaucoma in Patients Initially Followed up for Elevated Intraocular Pressure

PURPOSE

To report the lifetime risk of visual impairment resulting from glaucoma in patients originally followed up in a 10-year prospective randomized study initiated in 1981 to assess patients with elevated intraocular pressure (IOP).

DESIGN

Retrospective patient chart review.

PARTICIPANTS

Data on deceased patients who initially were followed up prospectively in the randomized controlled study and thereafter were followed up in ordinary clinical practice were collected until the end of 2017. Inclusion in the original study required an untreated IOP of 22 mmHg or more and 1 or more risk factors for glaucoma.

METHODS

Visual impairment, low vision, and blindness were defined according to the World Health Organization criteria. All eyes that became visually impaired were registered, including the date and cause of the impairment; the cumulative incidence of visual impairment corrected for competing risks was calculated; and the Kaplan-Meier method was used to analyze the importance of risk factors present at baseline for 1 eye per patient.

MAIN OUTCOME MEASURES

The proportion of patients who became bilaterally visually impaired because of glaucoma, the cumulative incidence of glaucoma-related visual impairment in at least 1 eye, and potential baseline risk factors for visual impairment caused by glaucoma.

RESULTS

Seventy-seven of 90 patients (86%) included in the initial randomized study were deceased at the end of 2017. Four patients were lost to follow-up during the clinical follow-up. Of the 77 patients, 7 (9%) became bilaterally visually impaired and 2 of those 7 became bilaterally blind because of glaucoma. The cumulative incidence of glaucoma-induced visual impairment in at least 1 eye increased from 0.00 after 5 years to 0.22 (95% confidence interval [CI], -0.01 to 0.67) after 30 years. The cumulative incidence of glaucoma blindness in at least 1 eye increased from 0.00 after 5 years to 0.17 (95% CI, 0.10-0.54) after 30 years. No specific risk factor significantly increased the risk of visual impairment caused by glaucoma.

CONCLUSIONS

Although the investigated patients showed elevated IOP and at least 1 additional glaucoma risk factor (i.e., they were high-risk patients), only a relatively small proportion of the patients with glaucoma demonstrated visual impairment.

Melatonin and the control of intraocular pressure

Melatonin is not only synthesized by the pineal gland but by several ocular structures. This natural indoleamine is of great importance for regulating several eye processes, among which pressure homeostasis is included. Glaucoma, the most prevalent eye disease, also known as the silent thief of vision, is a multifactorial pathology that is associated to age and, often, to intraocular hypertension (IOP). Indeed IOP is the only modifiable risk factor and as such medications are available to control it; however, novel medications are sought to minimize undesirable side effects. Melatonin and analogues decrease IOP in both normotensive and hypertensive eyes. Melatonin activates its cognate membrane receptors, MT₁ and MT₂, which are present in numerous ocular tissues, including the aqueous-humor-producing ciliary processes. Melatonin receptors belong to the superfamily of G-protein-coupled receptors and their activation would lead to different signalling pathways depending on the tissue. This review describes the molecular mechanisms underlying differential functionalities that are attributed to melatonin receptors. Accordingly, the current work highlights the important role of melatonin and its analogues in the healthy and in the glaucomatous eyes, with special attention to the control of intraocular pressure.

In vivo characterization of the deformation of the human optic nerve head using optical coherence tomography and digital volume correlation

We developed a method to measure the 3-dimensional (3D) strain field in the optic nerve head (ONH) in vivo between two intraocular pressures (IOP). Radial optical coherence tomography (OCT) scans were taken of the ONH of 5 eyes from 5 glaucoma patients before and after IOP-lowering surgery and from 5 eyes from 3 glaucoma suspect patients before and after raising IOP by wearing tight-fitting swimming goggles. Scans taken at higher and lower IOP were compared using a custom digital volume correlation (DVC) algorithm to calculate strains in the anterior lamina cribrosa (ALC), retina, and choroid. Changes in anterior lamina depth (ALD) relative to Bruch's membrane were also analyzed. Average displacement error was estimated to be subpixel and strain errors were smaller than 0.37%. Suturelysis decreased IOP by 9-20 mmHg and decreased compressive anterior-posterior strain Ezz in the ALC by 0.76% (p=0.002,n=5). Goggle-wearing increased IOP by 3-4 mmHg and produced compressive Ezz in the ALC (-0.32%,p=0.001,n=5). Greater IOP decrease was associated with greater ALD change (p=0.047,n=10) and greater strains in the ALC (Ezz:p=0.002,n=10). A deepening of ALD was associated with lower IOP and greater ALC strains (p⩽0.045,n=10). A DVC-based method to measure strains from OCT images caused by IOP changes as small as 2.3 mmHg provides preliminary evidence that ALD is shallower and ALC strains are less compressive at higher IOP and that ALD change is associated with ALC strains. STATEMENT OF SIGNIFICANCE: Glaucoma causes vision loss through progressive damage of the retinal ganglion axons at the lamina cribrosa, a connective tissue structure in the optic nerve head that supports the axons as they pass through the eye wall. It is hypothesized that strains caused by intraocular pressure (IOP) may initiate this damage, but few studies have measured the strain response to pressure of the optic nerve head in patients. We present a method to measure the 3D displacement and strain field in the optic nerve head caused by IOP alteration in glaucoma patients using clinically available images. We used this method to measure strain within the optic nerve head from IOP changes caused by glaucoma surgery and wearing tight-fitting swimming goggles.

Dark Adaptation Survey as a Predictive Tool for Primary Open-Angle Glaucoma

PURPOSE

To study the extent to which patients with primary open-angle glaucoma (POAG) have subjective difficulties with dark (DA) adaptation and vision under low-luminance conditions and to correlate the reported difficulties with severity of disease, specifically visual field loss.

DESIGN

Prospective, comparative case series.

PARTICIPANTS

Two hundred twenty patients with and without POAG who sought treatment at an outpatient subspecialty glaucoma clinic between October 2016 and September 2018.

METHODS

A questionnaire designed to assess difficulties with DA and vision under low luminance (the DA survey) was developed and given to patients during routine clinical evaluation in a hospital-based eye clinic. Retrospective data related to ocular health and glaucoma severity were abstracted from the medical record. A multiple regression analysis was performed to create a predictive model for POAG.

MAIN OUTCOME MEASURES

Severity of glaucoma, specifically visual field loss, and classification of participants as glaucoma patients or control participants.

RESULTS

Eighty-five patients with POAG and 127 control participants completed the questionnaire. Exploratory factor analysis of the DA survey using a principal components analysis showed that the items split into 2 dimensions: tasks that involved difficulty with vision under low luminance and those that required DA. Cronbach's α showed a high degree of internal consistency reliability (α = 0.88). Increasing DA survey score correlated with binocular visual field loss among patients with mild, moderate, and advanced POAG (P < 0.001). A model used to differentiate patients with POAG from control participants that included average and intereye difference in cup-to-disc ratio, family history of glaucoma, and DA survey score showed an accuracy, sensitivity, and specificity of 96.7%, 92.9%, and 99.2%, respectively.

CONCLUSIONS

This pilot study revealed that problems with DA and vision under low luminance are commonly encountered by patients with POAG. These areas of visual disability are not assessed routinely in glaucoma care. A questionnaire assessing vision under low luminance and light-dark transitions may serve as a proxy for functional impairment in glaucoma. When paired with risk factors such as structural features of the optic nerve and family history, this survey instrument may be suitable to screen for patients with POAG.