Glaucomatous Changes Research Articles

A clinical study of primary open angle glaucoma (POAG) in myopia-An observational study

The Primary open-angle glaucoma is the most common type of glaucoma causing irreversible blindness. Myopia is one of the risk factor responsible for pathogenesis of glaucoma. The association between myopia and primary open angle glaucoma has been found in numerous case studies. The aim of the study to evaluate the relationship of myopia in primary open-angle glaucoma by classifying the eyes into low, moderate and high myopia.This prospective study was performed on 1414 axial myopic patients more > 18 years. Clinical examination included, slit-lamp biomicriscopy, Goldman applanation tonometry, refraction, dilated optic disc assessment, central corneal thickness, visual field analysis and optical coherence tonography.Out of 1414 patients, 769(54.38%) were male and 645(45.62%) were female. Low myopia (<-3D) cases are 938(66.32%), moderate myopia (-3D to -D) 309(21.88%), high myopia (>-6D), 107(11.8%). Maximum number of cases were in younger age group (20-30 years). Intraoccular Pressure > 21mmHg in 143 cases of low myopia, 78 cases in moderate myopia, 72 cases in high myopia. There were 138 cases with glaucomatous field changes. Out of 138 cases 86(62.32%) were high myopia, 35(25.36%) were moderate myopia and 17(10.8%) cases were low myopia. The CUP-DISC ratio <0.5 in 75.95% cases, 0.5-<0.9 in 20.37% cases, >0.9 in 3.68% cases. The average values of circumpapilary Nerve Fiber Layer thickness in micrometer of low myopia, moderate myopia, high myopia, with non-glaucomatous cases were 98.9, 97.3, 93.5 and with glaucomatous cases, 74.4, 73.7 and 73.3 respectively. The average values of Ganglion Cell Complex thickness in micrometer in low, moderate and high myopia without glaucoma were 94.9, 93.5, 92.7 and with glaucoma 77.3, 74.6, 70.2 respectively. This study shows there is strong relationship between myopia and primary open-angle glaucoma. Early detection of glaucoma in myopic patients is necessary in delaying blindness.

Variance in the macular sublayers' volume as a diagnostic tool for primary open-angle glaucoma.

To assess the variance of macular sublayers' volume in glaucoma patients compared with normal individuals. This case-control observational study included 63 cases of primary open-angle glaucoma and 57 healthy controls. Macular volumetric scans were captured at the 6mm ETDRS circle for each retinal sublayer using Spectralis OCT2. The studied macular sublayers included the retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, and outer retinal layers (external limiting membrane to the retinal pigment epithelium). Standard deviation (SD) and coefficient of variation (CoV) of macular sublayers' volume were calculated. An unpaired Student t test (or its nonparametric equivalent) was used to compare each variable between groups. The receiver operating characteristic curve (ROC) was used to investigate the discriminative ability of each parameter. There was no significant difference for age or sex between the groups. The SD (of all sublayers' volume) was greater in the glaucomatous eyes compared with controls (0.620 ± 0.073vs.0.524 ± 0.056 mm3, respectively; P < 0.001). The same pattern was observed for CoV (7.890 ± 0.979vs.6.128 ± 0.583; P < 0.001). The area under curves (AUCs) for SD and CoV were 0.855and0.930, respectively (P = 0.05). The best cutoff value for the CoV was 6.712. The CoV and ganglion cell layer (GCL) volume revealed similar sensitivity (80.75) at 95% specificity for diagnosing glaucoma. The CoV detected 5 patients with glaucoma who had normal GCC volume. This study showed that the macular sublayers' volume variance parameters could be viable OCT biomarkers for detecting glaucomatous changes.

Differential effects of obstructive sleep apnea on the corneal subbasal nerve plexus and retinal nerve fiber layer.

PurposeObstructive sleep apnea (OSA) is an established independent risk factor for peripheral neuropathy. Macro and microvascular changes have been documented in OSA, including high levels of potent vasoconstrictors. In diabetes, vasoconstriction has been identified as an underlying risk factor for corneal neuropathy. This study sought to establish a potential relationship between OSA and corneal nerve morphology and sensitivity, and to determine whether changes in corneal nerves may be reflective of OSA severity.DesignSingle center cross-sectional study.MethodsSixty-seven patients were stratified into two groups: those with OSA and healthy controls. Groups were matched for age, sex, race, smoking, and dry eye status. Outcome measures included serologies, a dilated fundus exam, dry eye testing, anthropometric parameters, corneal sensitivity, subbasal nerve plexus morphology, retinal nerve fiber layer (RNFL) thickness, and the use of questionnaires to assess symptoms of dry eye disease, risk of OSA, and continuous positive airway pressure (CPAP) compliance.ResultsNo significant differences were observed in corneal nerve morphology, sensitivity, or the number of dendritic cells. In the OSA test group, RNFL thinning was noted in the superior and inferior regions of the optic disc and peripapillary region. A greater proportion of participants in the OSA group required a subsequent evaluation for glaucoma than in the control. In those with OSA, an increase in the apnea hypopnea index was associated with an increase in optic nerve cupping.ConclusionsOSA does not exert a robust effect on corneal nerves. OSA is however, associated with thinning of the RNFL. Participants with glaucomatous optic nerve changes and risk factors for OSA should be examined as uncontrolled OSA may exacerbate glaucoma progression.

Genome-wide transcriptome profiling of human trabecular meshwork cells treated with TGF-β2

Glaucoma is a complex neurodegenerative disease resulting in progressive optic neuropathy and is a leading cause of irreversible blindness worldwide. Primary open angle glaucoma (POAG) is the predominant form affecting 65.5 million people globally. Despite the prevalence of POAG and the identification of over 120 glaucoma related genetic loci, the underlaying molecular mechanisms are still poorly understood. The transforming growth factor beta (TGF-β) signalling pathway is implicated in the molecular pathology of POAG. To gain a better understanding of the role TGF-β2 plays in the glaucomatous changes to the molecular pathology in the trabecular meshwork, we employed RNA-Seq to delineate the TGF-β2 induced changes in the transcriptome of normal primary human trabecular meshwork cells (HTM). We identified a significant number of differentially expressed genes and associated pathways that contribute to the pathogenesis of POAG. The differentially expressed genes were predominantly enriched in ECM regulation, TGF-β signalling, proliferation/apoptosis, inflammation/wound healing, MAPK signalling, oxidative stress and RHO signalling. Canonical pathway analysis confirmed the enrichment of RhoA signalling, inflammatory-related processes, ECM and cytoskeletal organisation in HTM cells in response to TGF-β2. We also identified novel genes and pathways that were affected after TGF-β2 treatment in the HTM, suggesting additional pathways are activated, including Nrf2, PI3K-Akt, MAPK and HIPPO signalling pathways. The identification and characterisation of TGF-β2 dependent differentially expressed genes and pathways in HTM cells is essential to understand the patho-physiology of glaucoma and to develop new therapeutic agents.

Scleral Cross-Linking in Form-Deprivation Myopic Guinea Pig Eyes Leads to Glaucomatous Changes.

PurposeTo investigate the potential glaucomatous changes caused by scleral cross-linking (CXL) in a guinea pig form-deprivation (FD) myopia model.MethodsEighty 4-week-old tricolor guinea pigs were divided into four groups: FD only, genipin CXL only, FD plus CXL, and control. Refractive error, axial length (AL), intraocular pressure (IOP), and structural and vasculature optic disc changes in optical coherence tomography (OCT) and OCT angiography (OCTA) were measured at baseline and day 21. CXL efficacy was evaluated by scleral rigidity Young's modulus values. Histological and molecular changes in the anterior chamber angle, retina, and sclera were assessed.ResultsBaseline parameters were similar among groups (P > 0.05). The FD plus CXL group at day 21 had the least increase of AL (0.14 ± 0.08 mm) and highest IOP elevation (31.5 ± 3.6 mmHg) compared with the FD-only group (AL: 0.68 ± 0.17 mm; IOP: 22.2 ± 2.6 mmHg) and the control group (AL: 0.24 ± 0.09 mm; IOP: 17.4 ± 1.8 mmHg) (all P < 0.001). OCT and OCTA parameters of the optic disc in the FD plus CXL group at day 21 showed glaucomatous changes and decreased blood flow signals. Sclera rigidity increased in the CXL and FD plus CXL groups. Advanced glycation end products deposited extensively in the retina, choroid, and sclera of FD plus CXL eyes.ConclusionsCXL causes increased IOP and subsequent optic disc, anterior segment, and scleral changes while inhibiting myopic progression and axial elongation in FD guinea pig eyes. Therefore, applying CXL to control myopia raises safety concerns.

Assessment of visual field defects and optic disc changes in patients with high myopia

Glaucoma is a leading cause of global irreversible blindness. Primary open angle glaucoma (POAG) is the most common form of glaucoma and affects 44.1 million individuals worldwide. Furthermore, there is a disproportionate burden of POAG in Asia, with Asians accounting for 53% (23.5 million) of POAG cases worldwide. While early detection of POAG is important in delaying or halting the progression of the disease, a better understanding of the interplay between major risk factors for POAG is crucial. aim of this study is to assess the effects of myopia on POAG in the patient attending MYH Indore OPD (central India). It is a hospital based, prospective, non-randomised case study. 60 eyes of high myopic patients and 60 eyes of general Ophthal OPD patients were evaluated. The statistical software namely SPSS 19.0, were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc. In our study, we found that, in high myopic patient, there were increase in chances of glaucomatous optic disc changes, and these changes were influenced by age and not influenced with gender, degree of myopia.

Rates of Visual Field Change in Patients With Glaucoma and Healthy Individuals

Estimating the rate of glaucomatous visual field change provides practical assessment of disease progression and has implications for management decisions. To assess the rates of visual field change in patients receiving treatment for glaucoma compared with healthy individuals over an extensive follow-up period and to quantify the impact of important covariates for these rates. This prospective longitudinal cohort study was conducted in a hospital-based setting from January 1991 to February 2020. The study included 40 patients receiving treatment for open-angle glaucoma and 29 healthy participants. One eye of each participant was randomly selected as the study eye. Patients with glaucoma and healthy participants received testing with standard automated perimetry every 6 months. Individual rates of mean sensitivity change were computed using ordinary least-squares regression analysis, and linear mixed-effects modeling was used to estimate the mean rates of mean sensitivity change in the 2 groups and the impact of baseline mean sensitivity, baseline age, and follow-up intraocular pressure for rate estimates. Rate of mean sensitivity change in patients with glaucoma and healthy participants. A total of 40 patients with glaucoma (median age, 53.07 years [IQR, 48.34-57.97 years]; 21 men [52%]) and 29 healthy participants (median age, 48.80 years [IQR, 40.40-59.07 years], 17 women [59%]) were followed up for a median of 25.65 years (IQR, 22.49-27.02 years) and 19.56 years (IQR, 16.19-26.21 years), respectively. Most participants (65 individuals [94%]) self-identified as White, with the exception of 2 patients with glaucoma (1 self-identified as Black and 1 as South Asian) and 2 healthy participants (both self-identified as South Asian). The mean follow-up intraocular pressure of patients with glaucoma (median, 15.83 mm Hg [IQR, 13.05-17.33 mm Hg]) was similar to that of healthy participants (median, 14.94 mm Hg [IQR, 13.28-16.01 mm Hg]; P = .25). In an ordinary least-squares regression analysis, 31 patients (78%) with glaucoma had rates of mean sensitivity change within the range of healthy participants (ie, between -0.20 dB/y and 0.15 dB/y). Linear mixed-effects modeling revealed that the mean (SE) rate of mean sensitivity change in healthy participants was 0.003 (0.033) dB/y (95% CI, -0.062 to 0.068; P = .93). In comparison, patients with glaucoma had a mean (SE) rate of mean sensitivity change that was -0.032 (0.052) dB/y faster, but this difference was not statistically significant (95% CI, -0.134 to 0.070; P = .53). Among covariates, only baseline mean sensitivity was associated with the rate of mean sensitivity change (mean [SE], 0.021 [0.010] dB/y/dB; 95% CI, 0.002-0.041; P = .03). The results of this cohort study suggest that over a median follow-up of more than 25 years, the rate of visual field change in patients receiving treatment for glaucoma was comparable to that of healthy individuals. These findings could guide practitioners in making management decisions.

Age and sex affect TGFβ2-induced ocular hypertension in C57BL/6J mice

Glaucoma is a leading cause of blindness worldwide. The loss of vision in glaucoma patients is due to optic nerve damage. The most important risk factor of glaucoma is elevated intraocular pressure (IOP) which is due to glaucomatous changes in the trabecular meshwork. Animal models, especially mouse models for ocular hypertension (OHT), are important for studying glaucoma. Published studies showed that 2.5 × 107 PFU adenoviral vectors expressing the biologically active form of human TGFβ2 elevate IOP in female C57BL/6J mice when they are intravitreally delivered. In this study, we found that 2.5 × 107 PFU adenoviral TGFβ2 vector did not elevate IOP in 3- or 5-month old male C57BL/6J mice. In contrast, 5 × 107 PFU of the same viral vectors elevated IOP in both 3- and 5-month old male C57BL/6J mice. Also, 5-month old mice showed earlier OHT and higher IOP compared to 3-month old mice. In summary, our data showed that age and sex play roles in adenoviral vector-mediated TGFβ2-induced OHT in C57BL/6J mice.

Advanced Diffusion MRI of the Visual System in Glaucoma: From Experimental Animal Models to Humans.

Simple SummaryThis review summarizes current applications of advanced diffusion magnetic resonance imaging (MRI) throughout the glaucomatous visual system, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex. Glaucoma continues to be the leading cause of irreversible blindness worldwide and often remains undetected until later disease stages. The development of non-invasive methods for early detection of visual pathway integrity could pave the way for timely intervention and targeted treatment strategies. Principles of diffusion have been integrated with MRI protocols to produce a diffusion-weighted imaging modality for studying changes to tissue microstructures by quantifying the movement of water molecules in vivo. The development and applications of diffusion MRI in ophthalmology have allowed a better understanding of neural pathway changes in glaucoma. The feasibility of translating diffusion MRI techniques to assess both humans and experimental animal models of glaucoma and other optic neuropathies or neurodegenerative diseases is discussed. Recent research focuses on overcoming limitations in imaging quality, acquisition times, and biological interpretation suggest that diffusion MRI can provide an important tool for the non-invasive evaluation of glaucomatous changes in the visual system.Glaucoma is a group of ophthalmologic conditions characterized by progressive retinal ganglion cell death, optic nerve degeneration, and irreversible vision loss. While intraocular pressure is the only clinically modifiable risk factor, glaucoma may continue to progress at controlled intraocular pressure, indicating other major factors in contributing to the disease mechanisms. Recent studies demonstrated the feasibility of advanced diffusion magnetic resonance imaging (dMRI) in visualizing the microstructural integrity of the visual system, opening new possibilities for non-invasive characterization of glaucomatous brain changes for guiding earlier and targeted intervention besides intraocular pressure lowering. In this review, we discuss dMRI methods currently used in visual system investigations, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex. We evaluate how conventional diffusion tensor imaging, higher-order diffusion kurtosis imaging, and other extended dMRI techniques can assess the neuronal and glial integrity of the visual system in both humans and experimental animal models of glaucoma, among other optic neuropathies or neurodegenerative diseases. We also compare the pros and cons of these methods against other imaging modalities. A growing body of dMRI research indicates that this modality holds promise in characterizing early glaucomatous changes in the visual system, determining the disease severity, and identifying potential neurotherapeutic targets, offering more options to slow glaucoma progression and to reduce the prevalence of this world’s leading cause of irreversible but preventable blindness.

Can hemifacial spasm lead to glaucomatous changes?

To evaluate the association between hemifacial spasm (HFS) patients and glaucoma as a function of the Botox dosage required. A retrospective review of clinical documents and procedure records. Information of 76 consecutive patients (58 females) with HFS who received Botox treatment were reviewed. The age at onset of HFS was 66±11 (32-85) years, and all manifested unilaterally. Ten (13%, 95% confidence interval: 6.5-22.9%) patients were diagnosed with glaucoma, including 8 primary open-angle glaucoma (POAG) (4 unilateral and ipsilateral to the HFS), and 2 bilateral chronic angle-closure glaucoma (CACG). Nine of the 10 patients developed glaucoma after the onset of the HFS. The Botox dosage was significantly higher among those diagnosed with glaucoma (31+/8 vs. 26+/7units, P<0.05). There was a positive relationship between the presenting intraocular pressure (IOP) and the Botox dosage required (R=0.31, P=0.0116). However, there was a weak relationship between the Botox dosage required and the vertical cup to disc ratio (R=0.076, P=0.525). The presenting IOP of the HFS-affected eyes in those diagnosed with glaucoma was higher than those without glaucoma (19±3.5 vs. 13±3.2mmHg, P=<0.05). The presenting IOP between the HFS-affected and unaffected eyes was similar (16±4.8 vs. 15+/4.6mmHg, P=0.430). Smoking status, history of diabetes mellitus, hypertension, hyperlipidemia and obstructive sleep apnea were not different between HFS patients with or without glaucoma. Hemifacial spasm patients with glaucoma were associated with a higher Botox dosage. We found a positive relationship between the Botox dosage required and the presenting IOP. Whether hemifacial spasm can result in fluctuation of IOP, eventually causing glaucomatous damage, remains to be studied further.

Topographic Relationships among Deep Optic Nerve Head Parameters in Patients with Primary Open-Angle Glaucoma

Purpose: To investigate the topographic relationships among the deep optic nerve head (ONH) parameters representing myopic axial elongation or changes in the lamina cribrosa (LC) in patients with primary open-angle glaucoma (POAG). Methods: Among patients with POAG who visited the clinic between January 2015 and March 2017, the following deep ONH parameters were measured using spectral-domain optical coherence tomography (SD-OCT): externally oblique border tissue (EOBT) length, ONH tilt angle, optic canal (OC) obliqueness, and anterior LC insertion depth (ALID). In addition, the angular locations of the maximal value of each parameter were measured. We analyzed the correlations between the parameters, correlations with axial length (AL), and the spatial correspondence with glaucomatous ONH damage. Results: A total of 100 eyes with POAG were included in the analysis. The EOBT length, ONH tilt angle, and OC obliqueness were correlated with each other and with AL, whereas ALID showed less correlation with the other parameters and AL. The angular location where the three AL-related parameters had maximum values was also correlated with the predominant region of the glaucomatous ONH damage, while the angular location of the deepest ALID showed less correlation. Conclusions: Among the deep ONH parameters, the AL-related parameters EOBT length, ONH tilt angle, and OC obliqueness showed strong spatial correspondence with glaucomatous ONH damage, whereas the LC-related parameter ALID was less correlated with both AL and the region with glaucomatous ONH damage. Further studies are needed to determine how these differences affect glaucomatous ONH change.

Structural-Functional Glaucoma Progression Trajectory in 2-Dimensional Space.

We describe a method that provides rapid visualization of glaucomatous change in a 2-dimensional (2D) structural and functional (S/F) space. To describe a method to visualize glaucomatous change in a 2D S/F space. This was a retrospective longitudinal observational study. Group I included 64 normal and 64 glaucomatous eyes used to develop the structural score. Group II included 957 glaucomatous eyes used to plot the structural-functional progression vectors. Subjects were arranged in 2 groups. Group I was a cross-sectional group used to develop a structural score which were applied to longitudinal measurements of patients in group II for vectoral analysis. Visual field index was used as a functional score. Vectors were created for each eye to define structural (x) and functional (y) progression. The structural and functional components were calculated with linear models of optical coherence tomography scores and visual field index. The resultant vector and its confidence interval were plotted in 2D S/F space. Combined structural-functional glaucomatous progression. Group I included 64 normal and 64 glaucomatous eyes. We calculated 957 vectors (957 eyes of 582 OAG patients) in group II. The mean (±SD) follow-up period was 6.9 (±1.5) years and mean baseline mean deviation (MD) was -4.3 (±5.4). Preperimetric, mild, moderate, and severe groups included 159, 288, 299, and 211 eyes, respectively. Mean baseline MDs in these groups were 0.8, -1.0, -3.7, and -11.2 dB, and mean vector slopes were 0.88, 1.00, 1.98, and 2.69. We present a method that presents glaucoma progression in a 2D S/F space. This approach integrates a large amount of longitudinal numerical data and provides the clinician with a rapid and intuitive summary of the patient's glaucoma trajectory.

Pseudoexfoliation Syndrome

Pseudoexfoliation Syndrome (PEX) is a systemic disease characterised by the deposition of extracellular fibrillary material in the anterior segment of the eye. It is often identified incidentally on slit lamp examination because patients are typically asymptomatic during initial stages. It is associated with raised intraocular pressure and development of secondary glaucoma. Due to the increased disposition of PEG, patients with PEG should be routinely monitored so that early interventions could be introduced to slow down the progression of glaucomatous changes.

Impact of systemic steroids combined with immunosuppressive treatment on glaucomatous features in patients with systemic lupus erythematosus.

To evaluate the incidence of increased intraocular pressure (IOP) and glaucomatous changes in systemic lupus erythematosus (SLE) patients in comparison with systemic steroids and immunosuppressive treatment. Sixty-two women with SLE were divided into two groups: treated (n=47, 94 eyes) and not treated (n=15, 30 eyes) with systemic glucocorticosteroids (GC; GC-free). Twenty-one individuals in GC group were treated with immunosuppressive agents (immunomodulating and biologic). The visual acuity and IOP with ocular pulsatile amplitude (OPA) measurements, as well as scanning laser polarimetry (GDx) with nerve fiber index (NFI) measurement, spectral domain optical coherence tomography (SD-OCT) of the optic disk with retinal nerve fiber layer (RNFL) analysis and the macular region with ganglion cell analysis (GCA) were performed. Mean IOP values in group with combined GC and immunosuppressive therapy was 15.8±2.56 mm Hg and was significantly lower than in individuals with exclusive GC treatment (17.63±4.38 mm Hg, P=0.043). Contrary, no differences in mean IOP values between GC-free group and individuals treated with combined GC and immunosuppressive therapy were detected (P=0.563). Similarly, mean IOP in GC was 17.14±3.94 mm Hg and in GC-free patients was equal to 16.67±3.45 mm Hg (P=0.671). According to treatment regimen no statistical differences in optic disk SD-OCT for RNFL thickness, RNFL symmetry, cupping volume and the C/D ratio were observed. Similarly, no statistical differences for the mean and minimal ganglion cell layer (GCL) thickness measured in macular SD-OCT or NFI in GDx were detected. Combined immunosuppressive and systemic GC therapy in SLE patients may lower the risk of iatrogenic ocular hypertension. No relationship between treatment regimen and glaucomatous damage of optic nerve fibers in analyzed groups with SLE is detected.

Incidence of Glaucoma Progression and Rate of Visual Field Deterioration in a Cohort of Urban Ghanaians.

The annual incidence of glaucoma progression (9.7%) and rates of visual field mean deviation (MD) change in progressors (-1.02±0.06 dB/y) are high in a small cohort of urban Ghanaians. To report the incidence of glaucoma progression and the rate of visual field deterioration in a small cohort of Ghanaians. One hundred ten subjects (204 eyes) diagnosed with glaucoma at a baseline population-based screening examination were re-examined a mean of 8.3±0.8 years later. Eyes were classified as having progressed if the optic disc alone, visual field alone or both showed significant glaucomatous changes on follow-up. Visual field MD was used to calculate the rate of visual field progression. Progression was observed in 89 (80.9%, 9.7%/year) subjects (130 eyes). Progression occurred in 32 (31.7%, 3.8%/year) subjects by optic disc alone (46 eyes), 38 (44.7%, 5.4%/year) subjects by visual field alone (58 eyes), and 19 (25.0%, 3.0%/year) subjects by both modalities (26 eyes). The average rate of change in MD differed significantly between progressors (-1.02±1.06 dB/y) and nonprogressors (+0.089±0.49 dB/y), P =0.001. The rate of visual field worsening was greater among those who were classified as having progressed by both structure and function (-1.29±0.68 dB/y) and by function alone (-1.21±1.20 dB/y) than by structure alone (-0.55±0.76 dB/y). Progression was significantly associated with older age [odds ratio (OR), 1.42; P <0.001] and higher baseline intraocular pressure (OR, 1.18; P =0.002). Factors associated with rate of MD change were baseline older age (OR, 1.66; P =0.003), higher intraocular pressure (OR, 2.81; P =0.007), better visual field MD (OR, 1.41; P =0.004), and systemic hypertension (OR, 1.15; P =0.029). The incidence and rate of visual field progression are high in this longitudinal study of Ghanaian subjects with glaucoma. The findings may have important clinical and public health policy ramifications.

Impaired/dysfunctional aqueous collector channels may primarily contribute to the pathogenesis of primary open-angle glaucoma

Primary open-angle glaucoma (POAG) is induced by elevated intraocular pressure (IOP) that arises due to increased resistance in conventional aqueous humor outflow pathway (AHOc) consisting of trabecular meshwork (TM), Schlemm’s canal (SC), and downstream vascular network including collector channels (CCs). Although it has been traditionally considered that most of the outflow resistance lies in TM and the inner wall of SC, recent studies identified that more than one third of the resistance lies on CCs and their connected vascular network. In addition, CCs draw more attention because minimally invasive glaucoma surgery (MIGS) whose success depends upon them has been recently spotlighted in the treatment of POAG. Despite the importance of CCs during the pathogenesis of POAG, glaucomatous changes in CCs of human patients have been only considered as secondary results without direct evidence due to the absence of glaucoma animal model primarily induced by CC impairment as well as difficulty in definitive visualization of AHOcin vivo. Here, we hypothesize that likewise in TM and SC inner wall, structural and functional impairment of CCs may also primarily contribute to the initiation and progression of POAG. This article introduces a potential strategy to investigate and treat CC-related POAG.

The Curious Case of Night Blindness: A Rare Case Report

Introduction: Gyrate Atrophy of the choroid and the retina is a rare autosomal recessive disorder caused by a mutation in ornithine aminotransferase. Case Report: We present an interesting case of a 55-year-old male who presented to us with complaints of night blindness, increase in number of minus glasses, senile cataract in both eyes, constriction of peripheral visual field and chorioretinal atrophic lesions in both eyes. Blood investigation revealed raised plasma ornithine levels at 690 micromole/L (normal range 30-90 micromole/L). There is progressive night blindness and visual field constriction due to progressive chorioretinal degeneration. It has now progressed to diminution of central visual acuity due to progressive macular and glaucomatous changes and cataract formation. Conclusion: There is history of blindness in two out of 6 more siblings which indicates a hereditary pattern.

Management of glaucoma with Boston type 1 keratoprosthesis.

To describe the frequency, clinical characteristics, complications, and management of glaucoma in eyes that underwent keratoprosthesis implantation. Patients who underwent keratoprosthesis surgery between June 2010 and January 2020 were retrospectively evaluated for glaucoma association and prognoses. Among 17 patients who underwent keratoprosthesis surgery, 9 (52.9%) were associated with underlying or keratoprosthesis-induced glaucoma. Five eyes (29.4%) had underlying glaucoma and underwent a glaucoma drainage device implantation at least 6 months before keratoprosthesis surgery. One eye (5.9%) with normal intraocular pressure had glaucoma drainage device implantation at the same session with keratoprosthesis surgery due to high-risk characteristics of anterior segment structures. Four eyes with preexisting glaucoma showed progression after keratoprosthesis surgery. Additional antiglaucomatous treatment was commenced in two eyes whereas implantation of 2nd glaucoma drainage device was performed in two eyes. Postoperative complications in three eyes (100%) with glaucoma drainage device implanted 6 months before or at the same session with aphakic type keratoprosthesis surgery with partial vitrectomy included rhegmatogenous retinal detachment in two eyes and bacterial endophthalmitis in one eye. Migration of silicone oil through the tube to the subconjunctival area was seen after pars plana vitrectomy in one eye. None of the three eyes (0%) that underwent glaucoma drainage device implantation years before keratoprosthesis surgery experienced a posterior segment complication other than glaucomatous progression. Out of 11 eyes with no previous history of glaucoma, 3 (27.3%) showed high intraocular pressure and glaucomatous disc changes after keratoprosthesis surgery, which could be pharmacologically controlled. In this cohort, eyes with preexisting glaucoma were more difficult to manage compared to eyes with de novo glaucoma after keratoprosthesis surgery. Retinal complications appeared more often when glaucoma drainage device implantation was performed no more than 6 months before aphakic type keratoprosthesis surgery with partial vitrectomy.

Mitochondrial Dysfunction in Primary Open-Angle Glaucoma Characterized by Flavoprotein Fluorescence at the Optic Nerve Head

To investigate the presence of flavoprotein fluorescence (FPF) at the optic nerve head (ONH) rim as a marker of mitochondrial dysfunction in primary open-angle glaucoma (POAG) and control eyes. Retrospective cross-sectional study of patients recruited from the New York Eye and Ear Infirmary of Mount Sinai. A total of 86 eyes (50 eyes of 30 patients with POAG and 36 eyes of 20 control participants) were enrolled. The presence of POAG was defined by circumpapillary retinal nerve fiber layer thickness (cpRNFLT) of less than the bottom fifth percentile of the normative database, glaucomatous ONH changes, and visual field defects on 24-2 tests. Primary open-angle glaucoma and control eyes were imaged using the OcuMet Beacon. A 23°× 23° infrared scan was obtained, and an FPF scan was performed within a capture field spanning 13° in diameter. The ONH margins on the infrared image were identified by software algorithms. Then, FPF was measured within an elliptical annulus around the ONH rim, with the inner and outer boundaries corresponding to 0.5 to 1.1 times the ONH rim size. Flavoprotein fluorescence at the OHN rim in POAG and control eyes. Differences in FPF between POAG and control eyes were characterized through mixed-effects logistic regression, adjusted for age and interocular pressure. Flavoprotein fluorescence was significantly higher in POAG versus control eyes, with a mean ± SD of 46.4 ± 27.9 versus 28.0 ± 11.7 (P < 0.001), respectively. Among POAG eyes, FPF showed correlation to visual field mean deviation (P < 0.001), visual field pattern standard deviation (P= 0.003), and cpRNFLT (P= 0.001) on linear mixed-effects models. Higher FPF in POAG versus control eyes suggests the presence of mitochondrial dysfunction at the ONH rim in eyes with glaucomatous damage. The degree of FPF corresponds to disease severity, as measured by visual field and nerve fiber layer thickness metrics. Thus, FPF may represent a metabolic indicator of disease status that reveals the extent of injury in glaucoma.

New views on three-dimensional imaging technologies for glaucoma: an overview.

Purpose of reviewTo summarize the literature on three-dimensional (3D) technological advances in ophthalmology, the quantitative methods associated with this, and their improved ability to help detect glaucoma disease progression.Recent findingsImprovements in measuring glaucomatous structural changes are the result of dual innovations in optical coherence tomography (OCT) imaging technology and in associated quantitative software.SummaryCompared with two-dimensional (2D) OCT parameters, newer 3D parameters provide more data and fewer artifacts.